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Keysight N4372E, User Manual

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54

Keysight N4372E Lightwave Component Analyzer User’s Guide

4

Making Measurements

 

Measuring Opto-Electrical (OE) devices

Always perform an electrical calibration of the network analyzer or load an 

existing calibration set before you make a measurement.

Options -310 or -311 are required to perform OE measurements.

For standard measurements, see 

Electrical calibration for single-ended 

measurements

 on page 51.

For differential measurements, see 

Electrical calibration for differential OE 

measurements

 on page 52.

For differential OE measurements the single-ended (SE), logical port 1 is 

assigned to physical port 1 and the balanced (BAL), logical port 2 is 

assigned to the physical ports 2 and 3.

For OE measurements, the LCA sets up traces for S22, S21, S33, S31 by 

default. 

For more information, see 

Differential Measurements (applies to 4-port 

PNA only)

 on page 104.

Before you make your first opto-electrical measurement, you must 

initialize the OE measurement. You can see which measurement is 

currently initialized at the top left of the trace screen.

Summary of Contents for N4372E

Page 1: ...User s Guide Keysight N4372E Lightwave Component Analyzer ...

Page 2: ...equirements beyond those set forth in the EULA shall apply except to the extent that those terms rights or licenses are explicitly required from all providers of commercial computer software pursuant to the FAR and the DFARS and are set forth specifically in writing elsewhere in the EULA Keysight shall be under no obligation to update revise or otherwise modify the Software With respect to any tec...

Page 3: ...nt and Rear Panels 19 2 Setting Up the Instrument Unpacking the Lightwave Component Analyzer 24 Mounting the Test Set and the Network Analyzer 27 Installing the Millimeter Wave Network Analyzer System 27 Preparing the LCA Test Set Controller 28 Preparing the Network Analyzer 31 Setting up the Lightwave Component Analyzer 35 3 Performance Quick Check Preparation 40 Network analyzer settings and ele...

Page 4: ...nts 52 Electrical calibration for differential EO measurements 53 Measuring Opto Electrical OE devices 54 Initializing the OE measurement 55 Making single ended OE measurements 62 Making differential OE measurements applies to 4 port PNA only 63 Measuring Electro Optical EO Devices 64 Initializing the EO measurement 65 Making single ended EO measurements 67 Making differential EO measurements 68 R...

Page 5: ...ed 85 LCA System Settings 85 Optical Path Deembedding 86 RF Path Deembedding 88 Tools 90 Receiver 90 RF Power 90 Reset UI 91 6 Measurement Concepts General Measurement Techniques and Considerations 94 EO measurements lasers modulators 96 OE measurements photodiodes 97 OO measurements 97 Signal Relationships in Opto Electric Devices 98 Single Ended Measurements 103 Differential Measurements applies...

Page 6: ...nt 118 Preserving Connectors 120 Cleaning Instrument Housings 121 Which Cleaning Procedure should I use 121 How to clean connectors 122 How to clean connector interfaces 123 How to clean bare fiber adapters 124 How to clean lenses 125 How to clean instruments with a fixed connector interface 125 How to clean instruments with a physical contact interface 126 How to clean instruments with a recessed...

Page 7: ...LCA software 135 10 Definition of Terms Definition of Terms 138 11 Characteristics and Specifications Characteristics and Specifications 146 Declaration of Conformity 146 12 Regulatory and Warranty Information Regulatory Information 148 Declaration of Conformity 148 Warranty 149 System 149 Remove all doubt 149 Keysight E mail Updates 149 myKeysight 149 Keysight Open 150 Phone or Fax 150 Keysight O...

Page 8: ......

Page 9: ...Keysight N4372E Lightwave Component Analyzer User s Guide 1 Introduction Documentation 10 General Safety Considerations 10 Optical Test Set Front and Rear Panels 19 ...

Page 10: ...ations This product has been designed and tested in accordance with the standards listed on the manufacturer s Declaration of Conformity see Declaration of Conformity on page 148 and has been supplied in a safe condition The documentation contains information and warnings that must be followed by the user to ensure safe operation and to maintain the product in a safe condition Safety symbols CAUTI...

Page 11: ...s are used to mark the positions of the instrument power operating switch The recycling symbol indicates the general ease with which the instrument can be recycled The C Tick mark is the certification mark of the Australian Communications Authority The CE mark is the conformity marking of the European Community The CSA mark is the certification mark of the Canadian Standards Association WARNING If...

Page 12: ...mains before cleaning Use a dry cloth or one slightly dampened with water to clean the external case parts Do not attempt to clean internally WARNING Using controls or adjustments or performing procedures other than those specified in the documentation supplied with your equipment can result in hazardous radiation exposure CAUTION This product complies with over voltage Category II and Pollution D...

Page 13: ...e CAUTION Always use the three prong AC power cord supplied with this instrument Failure to ensure adequate earth grounding by not using this cord may cause instrument damage CAUTION This instrument has autoranging line voltage input Be sure the supply voltage is within the specified range CAUTION The Keysight N4372E Lightwave Component Analyzer LCA complies with over voltage category II and can o...

Page 14: ...on cord without a protective conductor Using an extension cord without a protective conductor means the instrument is not earthed Do not interrupt the protective earth connection intentionally Do not remove protective covers Operating personnel must not remove instrument covers Component replacement and internal adjustments must be made only by qualified service personnel Instruments that appear d...

Page 15: ...ed by pressing the active button close to the optical output connector on the front panel of the module by GUI or by remote command The optical output is emitting laser light when the green LED above the optical output on the front panel of the instrument is lit The built in laser diode is active whenever the instrument is powered on therefore disabling the output is not sufficient to establish ey...

Page 16: ...4 Table 1 Laser Source Specification N4372E 100 N4372E 102 N4372E E04 N4372E 101 N4372E 102 N4372E E04 Laser type DFB DFB Wavelength range 1310 20 nm 1550 20 nm Max CW output power of LCA 36 mW 36 mW Beam waist diameter 10 µm 10 µm Numerical aperture 0 1 0 1 Laser class according to IEC 60825 1 2014 1M 1M Max permissible CW output power 300 mW 163 mW Max CW output power is defined as the highest p...

Page 17: ...Laser Class 1M Label A sheet of laser safety labels is included with the laser module In order to meet the requirements of IEC 60825 1 2014 we recommend that you stick the laser safety labels in your language onto a suitable location on the outside of the instrument where they are clearly visible to anyone using the instrument ...

Page 18: ...ndoor use only This product complies with the WEEE Directive 2002 96 EC marking requirements The affixed label indicates that you must not discard this electrical electronic product in domestic household waste Product Category With reference to the equipment types in the WEEE Directive Annex I this product is classed as a Monitoring and Control instrumentation product Do not dispose in domestic ho...

Page 19: ...e ended measurements For further information on the front panel of the network analyzer refer to the documentation supplied with the network analyzer 1 LCA Test Set Controller 2 LCA Optical Receiver 3 LCA Optical Transmitter 4 Power switch Turns on the LCA Test Set Controller 5 Optical Input of LCA Optical Receiver Input port for the optical signal from the device under test CAUTION Do not apply m...

Page 20: ... 12 Port B RF output port of the LCA Optical Receiver to connect to the PNA CAUTION Do not apply any DC signal to this port 13 Function keys Used to control the Lightwave Component Analyzer Press the Macro Local Utility button on the network analyzer to display the LCA function keys Setup an LCA Measurement Perform a single sweep measurement with the current measurement setup Perform continuous sw...

Page 21: ... Rear Panel For information on the rear panel of the network analyzer please refer to the documentation supplied with the network analyzer 1 USB The software on the network analyzer uses the USB port to control the LCA Test Set Controller 2 Line power cable connector Plug in your power cable here ...

Page 22: ......

Page 23: ...2E Lightwave Component Analyzer User s Guide 2 Setting Up the Instrument Unpacking the Lightwave Component Analyzer 24 Mounting the Test Set and the Network Analyzer 27 Setting up the Lightwave Component Analyzer 35 ...

Page 24: ... selected 1x Millimeter wave Test Set Controller depending on the option selected 2x 3x or 4x Frequency extenders 1x N4372E LCA Test Set Controller 1x 8121 1242 USB cable 1x 0960 3245 Keyboard 1x 0960 3248 Mouse 1x 5972 3356 Calibration Report Notification 3x Local power cord 1x RoHS addendum for Photonic T M Accessories 1x RoHS addendum for Photonic T M products 1x N4372 90A05 Laser Safety Docume...

Page 25: ...eed Thru 1x N4372 87905 Patchcord PMF APC APC 1 5 m 2x N4372 87907 Patchcord PMF APC PC 0 5 m 3x 08154 61723 Connector Adapter FC 022 angled connector 2x 1005 1027 Feed Thru 1x N4372 87905 Patchcord PMF APC APC 1 5 m 2x N4372 87906 Patchcord PMF APC APC 0 5 m 3x 08154 61723 Connector Adapter FC For Option 311 combine options 301 and 310 IK1 Interconnect Kit for 2 Port PNA with 3 5 mm Ports N5292 6...

Page 26: ...idebar 2x N4372 40014 Trim Sidebar 2x N4373 25271 Bracket Adapter 1x N4373 25290 Bracket Rear Right 1x N4373 25291 Bracket Rear Left Refer also to the contents list of the network analyzer If anything is missing or defective contact your nearest Keysight Technologies sales office If the shipment was damaged contact the carrier then contact the nearest Keysight Technologies sales office ...

Page 27: ...5292 90002 For more information refer to the link http literature cdn keysight com litweb pdf N5292 90002 pdf Follow the steps below if you would like to mount the Millimeter Wave Network Analyzer System on top of the LCA Test Set Controller You can skip these steps if you prefer to have the LCA Test Set Controller separate from the Millimeter Wave Network Analyzer System CAUTION The Millimeter Wa...

Page 28: ... Test Set Controller 1 Use a Torx T15 screwdriver and the screws 0515 2317 to mount the left and right bracket adapter N4373 25271 to the rear side of the test head 2 Use the screws 0515 0433 and a Torx T20 screwdriver to attach the brackets N4373 25290 and N4373 25291 to the right and left bracket adapter ...

Page 29: ...lyzer User s Guide 29 Setting Up the Instrument 2 3 Turn the test head on its side and use a Pozidrive size 2 screwdriver to mount the adjustable feet 0403 1166 to the left and right brackets 4 Turn the test head back to its normal position ...

Page 30: ...30 Keysight N4372E Lightwave Component Analyzer User s Guide 2 Setting Up the Instrument ...

Page 31: ...r s Guide 31 Setting Up the Instrument 2 Preparing the Network Analyzer 1 Unlock all four feet of the Millimeter Wave Network Analyzer System to remove them from the bottom It is recommended to perform this step with at least two better three persons ...

Page 32: ...remove the 2 lower rear feet from the rear panel of the Millimeter Wave Network Analyzer System 3 Place the Millimeter Wave Network Analyzer System on top of the LCA Test Set Controller and align it with the mounting slots of the rear brackets It is recommended to perform this step with at least two better three persons ...

Page 33: ...rument 2 4 Use a Torx T20 screwdriver and the screws 0515 1619 to connect Millimeter Wave Network Analyzer System and left and right rear brackets 5 Use a Torx T20 screwdriver to attach the side bars N4372 21214 with the screws 0515 1269 to the left and right of the two instruments ...

Page 34: ...Guide 2 Setting Up the Instrument 6 Attach the adhesive trim covers to the left and right side bars to cover the screws optional 7 Use a 13mm wrench to level the adjustable feet to the other feet of the test head Use the upper nuts to lock the feet in place ...

Page 35: ...libration kit 45 N cm 4 lb in part number 8710 21813 to tighten the adapter 5 Attach the other side of the female to female rugged adapter to the LCA Optical Receiver 6 Repeat steps 3 and 4 to tighten the adapter 7 If you have option 310 or 311 plug the male Lemo connector of the LCA Optical Transmitter N4372 67986 N4372 67967 into the female Lemo receptacle on the LCA Test Set Controller 8 Repeat...

Page 36: ...apter can damage the electrical interface of the adapter and the connector on the LCA Optical Receiver Transmitter Avoid mechanical stress on the 1 0mm RF connection Ensure that the RF connectors of the electrical frequency extender head and the LCA Optical Receiver Transmitter are at the same height and longitudinally aligned when tightening the adapter If the height of the LCA Optical Receiver T...

Page 37: ... the power cables 18 Continue with Performance Quick Check on page 39 or Starting the Lightwave Component Analyzer on page 50 CAUTION Always use optical patch cords to connect to your DUT This protects the connectors of the LCA Optical Receiver Transmitter by minimizing the number of connector changes CAUTION Make sure to connect only matching connector types to the LCA Optical Receiver Transmitte...

Page 38: ...38 Keysight N4372E Lightwave Component Analyzer User s Guide 2 Setting Up the Instrument Figure 5 USB connection between the LCA Test Set Controller and the Network Analyzer ...

Page 39: ... and Optical CW Operation 42 Verifying the Electrical Connection and Electro optical Operation 46 This chapter shows how to Verify the optical and electrical connections to the N4372E Lightwave Component Analyzer Verify the performance of your N4372E Lightwave Component Analyzer Trouble shoot if you think there may be a malfunction ...

Page 40: ...r information on cleaning electrical connections Network analyzer settings and electrical calibration 1 On the network analyzer make the following settings Start Frequency 10 MHz Stop Frequency 110 GHz Number of points 11000 IF bandwidth 2000 Hz Averages 1 RF output power 15 dBm 2 Select Stepped sweep sweep moves in discrete steps 3 Calibrate the network analyzer electrically a Make sure the LCA h...

Page 41: ...tween port 1 and port 2 port4 depending on the configuration of the 110 GHz Network analyzer 3 Press the Macro Local utility button until the Macro 1 group is highlighted and you see 4 Click to start the LCA measurement setup 5 Select the EE Measurement tab 6 Click 7 Make a corrected measurement with the network analyzer 8 Inspect the results Electrical return loss S11 should be similar to S22 S44...

Page 42: ...and electrical calibration on page 40 2 If you have option 311 and 021 Connect the two straight angled optical patch cords N4373 87907 to the optical output of the LCA Optical Transmitter and input of the LCA Optical Receiver Note that the angled connector must be attached to the optical test set Use the FC PC adapter 1005 0256 to connect the straight ends of the optical patch cords If you have op...

Page 43: ...r your DUTs Laser power 3 dBm Optical input Input 1 User Calibration None Forward RF Power 0 dBm 7 Click then to set the output power 8 Press to start optical power meter application 9 Read the optical power from the power meter application The readout should be 3 dBm 0 5 dB 10 Press the Macro Local utility button until the Macro 1 group is highlighted and you see 11 Press to start the LCA measure...

Page 44: ...None Forward RF Power 0 dBm 14 Click then to set the output power 15 Press to start optical power meter application 16 Read the optical power from the power meter application The readout should be 1 dBm 0 5 dB 17 If you have option 301 and 021 Connect the straight angled optical patch cord N4373 87907 to the optical output of an external laser with 1310 nm or 1550 nm wavelength and known output po...

Page 45: ...art optical power meter application 22 Read the optical power from the power meter application The readout should be the power of the external laser 0 5 dB If the results are not as expected Try cleaning the optical connectors as described in Cleaning on page 114 With the laser switched off inspect all optical connectors with a microscope If the connectors on the N4373E Lightwave Component Analyze...

Page 46: ...373 87907 to the optical output of the LCA Optical Transmitter and input of the LCA Optical Receiver Note that the angled connector must be attached to the optical test set Use the FC PC adapter 1005 0256 to connect the straight ends of the optical patch cords If you have option 311 and 022 Connect the angled angled optical patch cords N4373 87906 to the optical output of the LCA Optical Transmitt...

Page 47: ...velength 1310 nm 1550 nm select the appropriate wavelength for your DUTs Laser power 3 dBm User Calibration None Forward RF Power 0 dBm 9 Click then to set the output power 10 Right click the measurement trace and select Autoscale All in the context menu At the end of the measurement there should be a flat trace An ideal trace might look like this ...

Page 48: ...tors seem to be damaged contact Keysight for repair or replacement Clean the electrical connectors on the N4372E Lightwave Component Analyzer and on the ruggedized 1 0 mm f to ruggedized 1 0 mm f adapter Make sure the connection to the network analyzer of the two flexible test port cables are tight Perform a new electrical calibration and retest If the problem persists contact Keysight for support...

Page 49: ...htwave Component Analyzer 50 Calibrating the Network Analyzer before Measurements 50 Measuring Opto Electrical OE devices 54 Measuring Electro Optical EO Devices 64 Returning to Electrical Measurements 69 Measuring Optical Optical OO Devices 70 Aborting a Measurement 76 Measuring Optical Power 76 ...

Page 50: ...n the network analyzer To get the best S N ratio for your measurements use the highest RF power your network analyzer can output without showing a source unlevelled error This can be more than the maximum specified output power of the network analyzer Decreasing the IF bandwidth improves the S N ratio of the measurement However doing so increases the calibration and measurement times so a suitable...

Page 51: ...arameters 2 From the Calibration menu select Other Cals Smart Cal 3 Select 2 Port Cal 4 On two port network analyzers select port 2 as selected 2nd port On 4 port network analyzers select port 4 as selected 2nd port If you plan to use other ports for your measurements select them for the calibration and later in the LCA software port configuration window For more information refer to Selecting Por...

Page 52: ... full four port calibration or a two port calibration between network analyzer ports 1 and 4 in addition to the three port calibration see Electrical calibration for single ended measurements on page 51 Calibrate before you start using the Lightwave Component Analyzer application Alternatively return to EE measurement mode as described in Returning to Electrical Measurements on page 69 to calibrat...

Page 53: ... Analyzer using an automated electrical calibration module follow these steps 1 Set your measurement parameters 2 From the Calibration menu select Smart Cal 3 Select 3 Port Cal 4 Select 3 Port Cal Configuration according to the planned port configuration for EO measurement and click the Next button Figure 6 Port configuration for the 3 port calibration 5 Select DUT connectors and the Cal Kits e g ...

Page 54: ...ential measurements see Electrical calibration for differential OE measurements on page 52 For differential OE measurements the single ended SE logical port 1 is assigned to physical port 1 and the balanced BAL logical port 2 is assigned to the physical ports 2 and 3 For OE measurements the LCA sets up traces for S22 S21 S33 S31 by default For more information see Differential Measurements applies...

Page 55: ...have already initialized the OE measurement you can connect your device under test and make the measurement by pressing or Please refer to the user s guide and online help of the network analyzer for further information Initializing the OE measurement 1 Press 2 Select the OE Measurement tab ...

Page 56: ...he value for the power emitted by the LCA Optical Transmitter output port Use an external power meter or the LCA power meter to measure the optical power The optical power is also displayed at the bottom of the LCA measurement setup screen 6 If you are running measurements in an unstable environment or need extra accuracy or long term stability make sure to select EverySweep or Continuous recommen...

Page 57: ...n in your setup see the section User Calibration under LCA System Settings on page 85 if you are not using Continuous modulator bias optimization The system is calibrated with a default setting You can determine the default setting by going to the Tools page choosing Reset UI and pressing Run 7 If you need to deembed optical components such as attenuators fiber optic cables or splitters located be...

Page 58: ...58 Keysight N4372E Lightwave Component Analyzer User s Guide 4 Making Measurements If you already have an s2p file for your device set Deembedding Data to File and enter or select the s2p file name ...

Page 59: ...eads located between the device under test and the input port open and enable the RF Path Deembedding Enter or select the file name 9 Select the appropriate type of user calibration for your measurement In many cases a User Calibration is not needed so select None The LCA measures to specifications under the standard conditions The frequency dependent transmission behavior of optical transmitters ...

Page 60: ...alibration can be used as the user calibration measurement in the CalSet for User Calibration combo box If you have performed a four port electrical calibration before use this one otherwise select the corresponding two port calibration The selected electrical calibration will only be used for the user calibration measurement Afterwards the LCA returns to the currently activated electrical calibra...

Page 61: ...tion is used for the user calibration measurement and for the DUT measurement b Select Reduce IF BW for user calibration measurement to reduce noise on the user calibration data The default bandwidth reduction factor is defined in the LCAConfig xml file c Click to proceed d Choose whether you want to save the calibration data for later use ...

Page 62: ... 1 Connect your device under test as illustrated below 2 When the following message is displayed click Single or Continuous to start the first measurement To make further measurements with these settings press or to start the measurement For information on further parameters refer to User Interface Reference on page 77 ...

Page 63: ... to 4 port PNA only 1 Connect your device under test 2 When the following message is displayed select Single or Continuous to start the first measurement 3 To make further measurements with these settings press click or to start the measurement For information on further parameters refer to User Interface Reference on page 77 ...

Page 64: ...easurements see Electrical calibration for differential EO measurements on page 53 For differential EO measurements the single ended SE logical port 1 is assigned to physical port 4 and the balanced BAL logical port 2 is assigned to physical ports 2 and 3 Figure 7 Topology configuration for differential measurements For EO measurements the LCA sets up traces for S22 S42 S33 S43 by default For more...

Page 65: ...measurement by pressing or Please refer to the user s guide and online help of the network analyzer for further information Initializing the EO measurement 1 Press 2 Select the EO Measurement tab only available for options 310 or 311 Figure 9 Graphical user interface of the LCA software 3 On a 4 port LCA select Differential or Single Ended Measure Mode depending on the type of your DUT 4 Select or...

Page 66: ... can enter the parameters of the optical path directly 6 If you need to deembed electrical components such as RF cables waveguide or other adapters or probe heads located between the output port and your device under test open and enable the RF Path Deembedding 7 If you are using a 75 Ohm minimum loss pad enable the RF Path Deembedding and make sure 75 Ohm is selected Enter or select the file with...

Page 67: ...atic measurement setup for single ended EO measurements 2 When the following message is displayed select Single or Continuous to start the first measurement Figure 11 Window to trigger LCA measurements 3 To make further measurements with these settings press or to start the measurement For information on further parameters refer to User Interface Reference on page 77 ...

Page 68: ...atic measurement setup for differential EO measurements 2 When the following message is displayed select Single or Continuous to start the first measurement Figure 13 Window to trigger LCA measurements 3 To make further measurements with these settings press or to start the measurement For information on further parameters refer to User Interface Reference on page 77 ...

Page 69: ...nitializing the EE Measurement as described here removes all the fixturing information in the network analyzer that is specific to the LCA Also the RF power on all ports is set to the power specified for Reverse RF Power dBm 1 Press 2 Make sure the EE Measurement tab is selected Figure 14 Graphical user interface of the LCA software 3 Click NOTE The recommended settings for Forward and Reverse RF ...

Page 70: ... for single ended measurements on page 51 Option 311 is required to perform OO measurements Before you make your first optical optical measurement you must switch to OO measurement mode You can see which measurement is currently initialized at the top left of the trace screen If you have already initialized the OO measurement you can connect your device under test and start the measurement by pres...

Page 71: ...r to measure the optical power 5 If you are running measurements in an unstable environment or need extra accuracy or long term stability make sure to select EverySweep or Continuous recommended for Modulator Optimization Please note optimizing every sweep adds about 1 second to each measurement Continuous modulator bias optimization superimposes a 10 kHz pilot tone onto the signal This improves t...

Page 72: ...The system is calibrated with a default setting You can determine the default setting by going to the Tools page choosing Default and pressing Run 6 If you need to deembed optical components such as attenuators fiber optic cables or splitters located between the laser output and your device under test open and enable the Optical Path Deembedding Here you can enter the parameters of the optical pat...

Page 73: ...transmission behavior of optical transmitters cannot be characterized as accurately as the behavior of receivers So for improved results at lower frequencies select Measure If you want to reuse an existing user calibration select Load and select the calibration file from the Windows Explorer window 8 Click to start the measurement preparation If User Calibration mode is set to Measure the followin...

Page 74: ... LCA returns to the currently activated electrical calibration for the DUT measurements The currently activated electrical calibration is preselected in the CalSet for User Calibration combo box This preselection is fine and you have nothing to do if the same electrical calibration is used for the user calibration measurement and for the DUT measurement b Select Reduce IF BW for user calibration m...

Page 75: ...1 Connect your device under test 2 When the following message is displayed select Single or Continuous to start the first measurement 3 To make further measurements with these settings press or to start the measurement For information on further parameters please refer to User Interface Reference on page 77 ...

Page 76: ...on in the LCA Server window Measuring Optical Power Press to measure the average optical power requires option 301 or 311 The optical power meter uses either the same Optical Input as the most recent measurement setup or the input specified on the Tools tab To set the optical input using the Tools tab follow these steps 1 Press 2 Select Input 2 as the Optical Input under Receiver on the Tools tab ...

Page 77: ...t N4372E Lightwave Component Analyzer User s Guide 5 User Interface Reference The LCA Function Keys 78 Default and Advanced Measurement Parameters 80 Saving and Loading Setups 80 The Measurement Parameters 82 ...

Page 78: ... setup an LCA measurement Perform a single sweep measurement with the current measurement setup Pressing this function key when a single or continuous measurement is running stops this measurement and starts a new single sweep measurement Perform continuous measurement sweeps with the current measurement setup Pressing this function key during a single or continuous measurement stops the measureme...

Page 79: ... in the program menu For information on further function keys please refer to the documentation supplied with the network analyzer NOTE After completing the LCA Measurement Setup step the network analyzer is ready for DUT measurements Because the receiver responsivity depends on the optical power you should start the DUT measurements with the LCA Single or Continuous macros These macros perform an...

Page 80: ...stem is configured to press Start from the LCA user interface There are two ways of saving setups First saving method Click to save the current setup If user calibration mode is set to Measure only possible for OE and OO measurements you are asked to specify the electrical calibration set to be saved with the setup This is the electrical calibration set to be used during user calibration measureme...

Page 81: ...ved with the setup If you selected Measure it is also possible to press the No button In this case only the LCA setup is saved If you press Yes you are asked for the filename of the LCA setup The name of the electrical calibration set just used for this user calibration measurement will be saved in the LCA setup Before the LCA saves the setup it asks you whether you want to save the network analyz...

Page 82: ...for the calibration data file during OE or OO initialization For more details see Measuring Opto Electrical OE devices on page 54 or Measuring Optical Optical OO Devices on page 70 The Measurement Parameters Measure Mode Figure 16 Graphical user interface of the LCA software A 2 port network analyzer can only support single ended measurements Selecting the Measure Mode is only possible if you have...

Page 83: ...ows the current port configuration as it is configured on the LCA server The LCA server stores specific port configurations for EO OE and OO measurements The assignment of source and receiver to either DUT or LCA in the configuration table depends on which measurement tab the dialog was opened from If Single Ended measurement is selected two columns are shown where you can select which port is con...

Page 84: ...yzer See network analyzer documentation for information about true mode differential measurements For differential OE measurements the network analyzer port to be used for the user calibration measurement can be selected independently If one of the differential ports is selected only a 3 port electrical calibration is required With the configuration shown above a 4 port electrical calibration woul...

Page 85: ...t network analyzer Single Ended If you select this mode the LCA uses a single ended electrical input or output for this measurement LCA System Settings Figure 19 Graphical user interface of the LCA software Wavelength nm If you have not selected to use the optional External Input select the wavelength of the laser source and the optical power meter use for measurements If you have selected to use ...

Page 86: ...ength and refractive index and attenuation Figure 20 Graphical user interface of the LCA software with enabled optical path deembedding based on optical parameters Length m and Refractive Index can only be used together That is you cannot give a value just for the refractive index or just the length The value for the Refractive Index of a single mode fiber is typically 1 467 at 1310 nm and 1 468 a...

Page 87: ...h Figure 21 Graphical user interface of the LCA software with enabled optical path deembedding based on a file selection These results need to be in the form of a 2 port S parameter data files also known as Touchstone s2p data files Only the s21 values of the file are used for correction of the transmission properties All other parameters are ignored To assign a file 1 Click at the right of the fi...

Page 88: ... 1 corresponds to the path to Port 2 on a two port network analyzer or respectively to Port 4 on a four port network analyzer For Differential measurements Src 1 corresponds to the path to Port 2 on the network analyzer Src 2 corresponds to the path to Port 3 on the network analyzer Rcv 1 corresponds to the path to Port 2 on the network analyzer Rcv 2 corresponds to the path to Port 3 on the netwo...

Page 89: ... recommend you use the AdapterChar macro supplied with the network analyzer This includes this directionality in its characterization Please refer to the online help on the Network Analyzer for further details To assign a file 1 Click 2 Locate and select the file in the explorer window 75 Ohm Select if you measure components with 75 Ohm impedance Insert the s2p file name for the file that characte...

Page 90: ...he other tabs Receiver Receiver Wavelength nm Set the wavelength to be used by the optical power meter RF Power Forward RF Power dBm Sets the RF power level for the source port s For balanced measurements on 4 port network analyzers Ports 2 and 3 of the network analyzer are forward for EO measurements and reverse for OE measurements Increasing the forward RF power for OE measurements increases the...

Page 91: ...eysight N4372E Lightwave Component Analyzer User s Guide 91 User Interface Reference 5 Reset UI The Reset UI button resets all LCA settings to default settings Figure 24 Tools section of the LCA software ...

Page 92: ......

Page 93: ...ncepts General Measurement Techniques and Considerations 94 Signal Relationships in Opto Electric Devices 98 Single Ended Measurements 103 Differential Measurements applies to 4 port PNA only 104 Triggering Concepts 109 Measuring at Different Wavelengths and with the External Optical Source Input 110 ...

Page 94: ...ghtwave components A precise electrical signal generator or optical laser source is used to stimulate the component under test and a very accurate optical or electrical receiver measures the transmitted signal Since characterization over a range of modulation frequencies is required the frequency of modulation is normally swept over the bandwidth of interest Measurements are typically comprised of...

Page 95: ...Definition of Terms 6 Figure 25 LCA Block Diagram Figure 25 demonstrates the basic concepts of lightwave component analysis An analysis of how various signals are used in the measurement process is found in Signal Relationships in Opto Electric Devices on page 98 ...

Page 96: ...ion of input modulating current and output optical modulation power Slope responsivity is used to describe how a change in input current produces a change in optical power Graphically this is shown in the following figure An LCA measures input modulating current and output modulation power and displays the ratio of the two in Watts Amp either linearly or in decibels ...

Page 97: ...e below The LCA measures the input optical modulation power and output modulation current and displays the ratio of the two in Amps Watt OO measurements Characteristics of purely optical devices can also be measured In this case both the stimulus and response are modulated light The ratio measurement is simply one of gain or loss versus modulation frequency As the lightwave component analyzer is a...

Page 98: ...ollowing section will discuss how similar techniques are used in characterizing devices in the lightwave domain This is intended to show the basis on which EO and OE responsivity measurements are defined The figure below is a general representation of a lightwave system showing input and output signals in terms of terminal voltages input and output currents and optical modulation power S parameter...

Page 99: ...rical current or voltage The overall system forward gain is defined as Though the overall system gain is defined as an S parameter the individual transfer functions of the EO and OE devices are typically defined in terms of responsivities because signals in both the optical and electrical domain are used and optical signals do not lend themselves conveniently to S parameter definitions Initially t...

Page 100: ...s and Using the above relationships we can rewrite S21 in terms of the transducer responsivities Rs and Rr It is convenient to express the transducer functions logarithmically in decibels The system power gain from a Z0 source to a Z0 load can be defined using the above relationships ...

Page 101: ...just as 0 dB represents an S21 of unity or gain of 1 Consequently source responsivity will be expressed in Watts per Amp which in decibels will be related to a conversion efficiency of 1 W A Similarly receiver conversion efficiency will be relative to 1 A W The individual responsivities can now be expressed individually in decibels This now allows us to express the original equations for responsiv...

Page 102: ...curately measure optical modulation power P0 and modulation current I1 2 The measurement of modulation current is derived from the system characteristic impedance and a measurement of electrical power The measurement of optical modulation power is based on a standard lightwave receiver whose characteristics are predetermined and known by the LCA Δ Δ ...

Page 103: ...inition of Terms 6 Single Ended Measurements Single port measurements are made on devices when the signal on the electrical port is referenced to ground This port is described by S parameters Figure 26 Single ended EO measurement Figure 27 Single ended OE measurement ...

Page 104: ...is a third port For valid differential measurements make sure the electrical calibration of the network analyzer includes at least three ports For more details on differential measurements please consult the network analyzers user s guide For differential device measurements the LCA assumes fixed port configuration The physical ports 1 and 4 on the network analyzer connect to the LCA test set The ...

Page 105: ...zer need to be set as follows Logical port 1 is assigned to the single ended unbalanced port and Logical port 2 is assigned to the balanced differential port Differential OE measurements For OE measurements the single ended SE logical port 1 is assigned to physical port 1 and the balanced BAL logical port 2 is assigned to the physical ports 2 and 3 see Figure 30 Figure 30 Logical Port Mapping for ...

Page 106: ...signed to physical ports 2 and 3 see Figure 31 Figure 31 Logical Port Mapping for EO measurement For EO measurements the LCA sets up traces for S22 S42 S33 S43 by default Differential results When measuring differential devices the network analyzer displays traces of interest for balanced devices These include differential responsivity S common mode rejection or port imbalance Since opto electroni...

Page 107: ...zer This calibration establishes the electrical calibration reference planes for the measurements to be at the RF output port of the frequency extender heads Whenever there are additional electrical adapters or elements required for connecting the device under test these electrical paths can be accounted for by RF path deeembedding see RF Path Deembedding on page 88 The second stage is the calibra...

Page 108: ... and includes the two Y1900D ruggedized 1 0 mm adapters supplied and connected to the optical test set The calibration is with respect to the optical connectors on the front of the optical test set Whenever there are additional optical adapters or elements connecting to the device under test these optical paths can be accounted for by optical path deeembedding see Optical Path Deembedding on page ...

Page 109: ...eans more accurate results than a measurement started directly on the network analyzer During LCA Measurement Setup it is assumed that the DUT has no optical loss and the receiver deembedding is setup for a DC power level equal to the selected optical output power of the LCA When the internal light source is not used EO measurement in Default mode the receiver deembedding is setup for a DC power l...

Page 110: ...en the closest internal wavelength and the wavelength you select it is important that you measure the Rx responsivity for every internal wavelength and your additional wavelengths Follow the following procedure 1 In Tools Tab set the receiver wavelength to either 1550 nm or 1310 nm 2 Apply an external laser source at wavelength set to the internal wavelengths 1310 nm and or 1550 nm and known power...

Page 111: ...correction file the correction factor is calculated from the values found in the file This correction factor is applied to the values from the internal optical power meter and to the calibration data used for the LCA measurements OE measurements On the OE tab of the LCA user interface if you check the external laser input check box you can edit the wavelength The principles described for EO measur...

Page 112: ...112 Keysight N4372E Lightwave Component Analyzer User s Guide 6 Definition of Terms OO measurements The principles described above for EO and OE measurements also apply to OO measurements ...

Page 113: ...ntenance Cleaning 114 This system should be serviced only by authorized personnel WARNING Using controls or adjustments or performing procedures other than those specified in the documentation supplied with your equipment can result in hazardous radiation exposure ...

Page 114: ...ase follow the following safety rules Do not remove instrument covers when operating Ensure that the instrument is switched off throughout the cleaning procedures Use of controls or adjustments or performance of procedures other than those specified may result in hazardous radiation exposure Make sure that you disable all sources when you are cleaning any optical interfaces Under no circumstances ...

Page 115: ...ortunately when comparing most published cleaning recommendations you will discover that they contain several inconsistencies In this section we want to suggest ways to help you clean your various optical devices and thus significantly improve the accuracy and repeatability of your lightwave measurements What do I need for proper cleaning Some Standard Cleaning Equipment is necessary for cleaning ...

Page 116: ... and then use compressed air to blow away any remaining filaments If possible avoid using denatured alcohol containing additives Instead apply alcohol used for medical purposes Never try to drink this alcohol as it may seriously damage your health Do not use any other solvents as some may damage plastic materials and claddings Acetone for example will dissolve the epoxy used with fiber optic conne...

Page 117: ...d never apply them twice Any dust and dirt from the air which collects on your tissue or which has gathered after initial cleaning may scratch and pollute your optical device Pipe cleaner Pipe cleaners can be purchased from tobacconists and come in various shapes and sizes The most suitable one to select for cleaning purposes has soft bristles which will not produce scratches There are many differ...

Page 118: ...rocedures need the following equipment which is not required to clean each instrument Microscope with a magnification range about 50X up to 300X Ultrasonic bath Warm water and liquid soap Premoistened cleaning wipes Lens cleaning papers Polymer film Infrared Sensor Card Microscope with a magnification range about 50X up to 300X A microscope can be found in most photography stores or can be obtaine...

Page 119: ...n iridescent film after it has been air dried Some lenses and mirrors also have a special coating which may be sensitive to mechanical stress or to fat and liquids For this reason we recommend you do not touch them If you are not sure how sensitive your device is to cleaning please contact the manufacturer or your sales distributor Premoistened cleaning wipes Use pre moistened cleaning wipes as de...

Page 120: ...not touch the outside of the mating connector or adapter Otherwise you will rub the fiber end against an unsuitable surface producing scratches and dirt deposits on the surface of your fiber Dust Caps and Shutter Caps Be careful when replacing dust caps after use Do not press the bottom of the cap onto the fiber as any dust in the cap can scratch or dirty your fiber surface When you have finished ...

Page 121: ... the keypad In the case of heavy dirt you can moisten the cotton tissue in water Which Cleaning Procedure should I use Light dirt If you just want to clean away light dirt observe the following procedure for all devices Use compressed air to blow away large particles Clean the device with a dry cotton swab Use compressed air to blow away any remaining filament left by the swab WARNING Do not open ...

Page 122: ...e connector This depends on the degree of dirtiness or the depth of the scratches This is a difficult procedure and should only be performed by skilled personal and as a last resort as it wears out your connector To assess the projection of the emitted light beam you can use an infrared sensor card Hold the card approximately 5 cm from the output of the connector The invisible emitted light is pro...

Page 123: ...n connector interfaces Preferred Procedure Use the following procedure on most occasions 1 Clean the interface by pushing and pulling a new dry pipe cleaner into the opening Rotate the pipe cleaner slowly as you do this 2 Blow away any remaining lint with compressed air Procedure for Stubborn Dirt Use this procedure particularly when there is greasy dirt on the interface 1 Moisten a new pipe clean...

Page 124: ...ning Rotate the pipe cleaner slowly as you do this 2 Clean the adapter by pushing and pulling a new dry pipe cleaner into the opening Rotate the pipe cleaner slowly as you do this 3 Clean the adapter by rubbing a new dry cotton swab over the surface using a small circular movement 4 Blow away any remaining lint with compressed air CAUTION Never use any kind of solvent when cleaning a bare fiber ad...

Page 125: ...rcular movement 2 Blow away any remaining lint with compressed air Procedure for stubborn dirt Use this procedure when there is greasy dirt on the lens 1 Moisten a new cotton swab with isopropyl alcohol 2 Clean the lens by rubbing the cotton swab over the surface using a small circular movement 3 Using a new dry cotton swab remove the alcohol any dissolved sediment and dust 4 Blow away any remaini...

Page 126: ...f the degree of pollution on the surface of your interface and to check whether it has been removed after cleaning you need a microscope To assess the projection of the emitted light beam you can use an infrared sensor card Hold the card approximately 5 cm from the interface The invisible emitted light is projected onto the card and becomes visible as a small circular spot CAUTION Only use clean d...

Page 127: ...ement 4 Blow away any remaining lint with compressed air How to clean instruments with a recessed lens interface For instruments with a deeply recessed lens interface for example the Keysight Technologies 81633A and 81634A Power Sensors do not follow this procedure Alcohol and compressed air could damage your lens even further Keep your dust and shutter caps on when your instrument is not in use T...

Page 128: ...r movement 4 Blow away any remaining lint with compressed air How to clean optical devices which are sensitive to mechanical stress and pressure Some optical devices such as Reference Reflectors are very sensitive to mechanical stress or pressure Do not use cotton swabs soft tissues or other mechanical cleaning tools as these can scratch or destroy the surface Preferred procedure Use the following...

Page 129: ...ompressed air If there are any streaks or drying stains on the surface repeat the cleaning procedure How to clean bare fiber ends Bare fiber ends are often used for splices or together with other optical components to create a parallel beam The end of a fiber can often be scratched You make a new cleave To do this do the following 1 Strip off the cladding 2 Take a new soft tissue and moisten it wi...

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Page 131: ...peration of the Lightwave Component Analyzer 132 This system should be serviced only by authorized personnel WARNING Using controls or adjustments or performing procedures other than those specified in the documentation supplied with your equipment can result in hazardous radiation exposure ...

Page 132: ...ribed in Starting the Lightwave Component Analyzer on page 50 4 Perform the performance verification as described in Performance Quick Check on page 39 Event Log Further troubleshooting information is available from the event log You can find this log in the bin subdirectory of the directory where the LCA program is installed If you want to refer to the log save a copy of it before you restart the...

Page 133: ...Keysight N4372E Lightwave Component Analyzer User s Guide 9 Reinstalling and Updating the Software Backing Up your LCA Data 134 Reinstalling the LCA Software 134 ...

Page 134: ... analyzer s system recovery process Please refer to the user documentation of the network analyzer for information on backing up calibration data Reinstalling the LCA Software There are two cases Updating the LCA software Reinstalling the LCA software completely for example after recovering the network analyzer Updating the LCA software 1 Before updating the software you must remove the existing s...

Page 135: ... on the screen We recommend you use the default settings Note the directory to which the LCA application is installed 3 The registry script in the next step installs LCA related functions in the first 6 positions of the network analyzers macro group Macro 1 In this LCA directory right click on the file NWAShortcuts reg 4 From the context menu select Merge Restoring the hardware calibration files 1...

Page 136: ......

Page 137: ...Keysight N4372E Lightwave Component Analyzer User s Guide 10 Definition of Terms Definition of Terms 138 ...

Page 138: ...al The variation of the optical Average output power optical P over time calculated as where maxt and mint are the maximum and minimum value over time t Conditions Time period as specified after modulator auto bias modulator optimization is performed with the selected wavelength Other conditions as specified Measurement Using an average power meter with averaging time set to 1 s Average output pow...

Page 139: ...ange for the average optical power where the specification for Average power measurement uncertainty optical applies Decibel dBm dBo dBe A ratio in decibel dB is calculated as 10 log10 ratio Special cases dBo specifically the ratio of optical powers o for optical dBe specifically the ratio of electrical powers e for electrical dBm power level related to 1 mW electrical or optical dBW A The square ...

Page 140: ...d cables and unchanged connections Other conditions as specified Measurement using a stable DUT Group delay GD The signal delay time caused by a transmission path component The group delay is derived from the phase change dφ of a harmonic signal detected after the path component resulting from a small frequency change dfmod of the signal with phase change dφ expressed in degrees Group delay uncert...

Page 141: ...n a DUT with zero output expressed in Decibel dBm dBo dBe The value is calculated by averaging the measured responsivity in linear space rather than decibel space over the modulation frequency within a specified modulation frequency range Conditions As specified Modulated optical power The amplitude of a harmonic optical power modulation The modulated optical power is calculated from the peak opti...

Page 142: ...the Modulated optical power divided by Average output power optical Condition modulation frequency as specified Operating input wavelength range The wavelength range on the LCA optical input for which the LCA system is designed NOTE Modulated optical power divided by average optical power is a value between 0 no modulation and 1 full modulation See OMI optical modulation index NOTE For full modula...

Page 143: ...ency response uncertainty When taking the difference between measured Responsivity of a device under test and actual true responsivity in dBe over modulation frequency the system relative frequency response uncertainty is half the peak to peak difference Conditions Modulation frequency range as specified Other conditions as specified Measurement Based on a reference RF O E receiver Responsivity Th...

Page 144: ... power in Watt expressed in A W In both cases responsivity in Decibel dBm dBo dBe dBW A or dBA W is calculated as 20 log R O O measurement R is the difference between the Modulated optical power in dBm at the DUT output and at the DUT input expressed in dBo If expressed in dBe it is twice this number References Guide to the Expression of Uncertainty in Measurement GUM BIPM IEC ISO et al 1993 NOTE ...

Page 145: ...Keysight N4372E Lightwave Component Analyzer User s Guide 145 User Interface Reference 11 11 Characteristics and Specifications Characteristics and Specifications 146 Declaration of Conformity 146 ...

Page 146: ... of the N4372E refer to the datasheet at https www keysight com us en assets 3119 1065 data sheets 5992 4 215 pdf Declaration of Conformity Declarations of Conformity for this product and for the Keysight products may be downloaded from the Web Go to http www keysight com go conformity You can then search by product number to find the latest Declaration of Conformity ...

Page 147: ...t N4372E Lightwave Component Analyzer User s Guide 12 Regulatory and Warranty Information Regulatory Information 148 Declaration of Conformity 148 Warranty 149 Phone or Fax 150 Keysight Online Information 151 ...

Page 148: ...liance with Canadian EMC Requirements This ISM device complies with Canadian ICES 001 Cet appareil ISM est conforme à la norme NMB 001 du Canada Declaration of Conformity For latest DoC please visit the web link http www keysight com go conformity Acoustic Noise Emission LpA 50 dB Operator position Normal operation per ISO 7779 ...

Page 149: ...Keysight offers a wide range of additional expert test and measurement services for your equipment including initial start up assistance onsite education and training as well as design system integration and project management Our repair and calibration services will get your equipment back to you performing like new when promised You will get full value out of your Keysight equipment throughout i...

Page 150: ...nectivity for a broad range of system ready instruments open industry software PC standard I O and global support which are combined to more easily integrate test system development www keysight com find open Phone or Fax United States tel 800 829 4444 fax 800 829 4433 Canada tel 877 894 4414 fax 800 746 4866 China tel 800 810 0189 fax 800 820 2816 Europe tel 31 20 547 2111 Japan tel 81 426 56 783...

Page 151: ...www keysight com find pol Spectral analysis products www keysight com find osa Electro optical converters www keysight com find ref Optical test instruments accessories www keysight com find octaccessories Firmware and driver download www keysight com find octfirmware Keysight photonic discussion forum http www keysight com find photonic_forum For Network analyzer related literature please visit K...

Page 152: ...This information is subject to change without notice Keysight Technologies 2020 Edition 1 0 April 2020 Printed in Germany www keysight com ...

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