General Photonics PMDPro PMD-1000 Operation Manual Download Page 6 | Manualshive

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Document #: GP-UM-PMD-1000-21

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Section 2. Overview:

General Photonics’ PMDPro™ is a breakthrough PMD source that can deterministically
generate precise 1

st

-order PMD up to 180 ps and 2

nd

-order PMD up to 8100 ps

2

. It

combines this basic functionality with a rapid switching time (~1 ms) and polarization
optimization capability to enable various applications related to high bit-rate optical fiber
communication links. PMDPro simplifies and expedites all PMD related systems testing.

Figure 1 System diagram of polarization optimized PMD source

The PMDPro contains an automatic polarization controller and two polarimeters that
continuously monitor the state of polarization (SOP) and degree of polarization (DOP)
before and after the PMD generating elements. The polarization controller can be
operated using feedback from the input polarimeter to automatically align and maintain
the input SOP such that there is an equal power split between polarization components
aligned to the principal axes of the DGD element to obtain the worst-case first order
PMD effect. Alternatively, the controller can automatically adjust and maintain the input
SOP using the feedback from the output polarimeter to either minimize or maximize the
output DOP for each PMD setting.

Minimizing the output DOP enables testing of the worst-case total PMD effect, while
maximizing the output DOP allows the PMDPro to act as a PMD compensator, allowing
the user to determine the optimum PMD values for PMD compensation. The PMDPro
can also perform PMD emulation by generating statistical distributions of first and
second order PMD representing those of a real fiber link. In addition, the integrated
polarization controller and polarimeters enable variable rate scrambling and deterministic
polarization control functions, including trace generation and polarization stabilization at
any SOP.

Basic functions can be controlled either manually from the front panel keypad or
remotely via RS-232, USB, Ethernet, or GPIB interfaces. The control program also
enables several advanced functions.

The structure, features, and functions of the PMDPro are described in more detail in
sections 3 and 4. Section 5 includes application examples, and section 6 describes basic
troubleshooting.

DSP

Polarimeter2

Polarimeter1

PC

1

st

& 2

nd

order PMD Generator

Interfacing electronics

Input

Output

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8
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Summary of Contents for PMDPro PMD-1000

Page 1: ...ion Optimized PMD Source Operation Manual Version 2 1 November 16 2015 General Photonics Corp Ph 909 590 5473 5228 Edison Ave Fax 909 902 5536 Chino CA 91710 USA www generalphotonics com Document GP UM PMD 1000 21 Page 1 of 122 ...

Page 2: ... assumes no liability for customers failure to comply with these requirements Before operation the user should inspect the instrument and review the manual carefully The instrument s rear panel includes a chassis ground terminal for electrical safety Make sure that the instrument is in a secured work environment in terms of temperature humidity electrical power hazard due to fire or shock etc for ...

Page 3: ...2 Installation 46 4 3 3 RS 232 Connection 49 4 3 4 USB Connection 49 4 3 5 GPIB Connection 50 4 3 6 Ethernet Connection 50 4 3 7 Control Program Interface 55 Monitor Screen 56 Front Panel Functions 58 PMDE 58 SOP 61 PMDC 63 MONITOR 64 MANUAL 65 Advanced Functions 66 ADVANCED PMDE 66 PMD Measurement and Long term Monitoring 80 PMD Measurement 80 Long Term PMD Monitor 86 Setup 88 Store Recall 89 PMD...

Page 4: ...D source 111 5 5 The polarization optimized PMD source 111 5 6 Advantages and applications of the polarization optimized PMD source 114 Section 6 Troubleshooting 116 Section 7 Technical Support 117 Appendix A ITU Grid Channel Lookup Table 118 Document GP UM PMD 1000 21 Page 4 of 122 ...

Page 5: ...D Resolution 90 ps range 180 ps range Discrete mode 0 357 ps 0 714 ps Quasi continuous mode 0 1 ps 0 2 ps 2nd order PMD Range 2000 ps2 90 ps range 8100 ps2 180 ps range PMD Variation Time 1 ms minimum SOP Alignment Accuracy 2 at 23 5 C SOP Tracking Speed 10π s DOP Accuracy 2 at 23 5 C PDL 0 45 dB typical 90 ps version 0 5 dB typical 180 ps version Wavelength Dependent Loss 0 6 dB across C band Tra...

Page 6: ...atively the controller can automatically adjust and maintain the input SOP using the feedback from the output polarimeter to either minimize or maximize the output DOP for each PMD setting Minimizing the output DOP enables testing of the worst case total PMD effect while maximizing the output DOP allows the PMDPro to act as a PMD compensator allowing the user to determine the optimum PMD values fo...

Page 7: ... However high insertion loss or measurement instability that does not improve after cleaning the external connectors may indicate that the instrument s internal connector ferrules require cleaning Each connector ferrule is contained in a universal connector interface consisting of a front piece that connects to the external fiber connector and a base piece that is mounted on the front panel of the...

Page 8: ... switch Power liquid crystal display LCD push button control pads and input output optical connectors are mounted on the front panel The AC power plug fuse chassis ground connector RS 232 USB Ethernet and GPIB interface connectors and two fans are mounted on the rear panel as shown in Figure 4 The PMDPro includes RS 232 USB Ethernet and GPIB interfaces for external computer operation of the system...

Page 9: ...nput and output polarimeters as well as output power and PMD information PMDC DGD and PMD compensation functions MANUAL SOP control via direct real time setting of individual polarization controller channel voltages STORE Allows user to store sequences of PMD values for scans or to store individual PMDC measurement results RECALL Allows user to recall stored PMD sequences or PMDC measurement resul...

Page 10: ...B USB interface port RS 232 serial communication port Ethernet Ethernet interface port BNC not used in PMD 1000 GPIB GPIB interface port Line external AC supply input connector 100 240VAC chassis ground connector Document GP UM PMD 1000 21 Page 10 of 122 ...

Page 11: ...cture and operational principles of the PMDPro are described in section 2 This section describes operational procedures and control sequences for control of the PMDPro s basic functions from the front panel Setup procedure is described below 1 Make sure local AC voltage matches the AC voltage requirement of the PMDPro If not do not proceed Contact General Photonics immediately The PMDPro power sup...

Page 12: ...s the power level at the output polarimeter in mW µW and dBm and the DGD and SOPMD values currently being generated by the PMDPro in ps and ps2 respectively If no light is detected the PMDPro will display a Power Low message instead of the information described above Pressing the MONITOR button from any other operation or setup mode will stop any active polarization control or DGD scanning and ret...

Page 13: ...e between menu options and the ENTER key the center key in the arrow keypad to select the desired option 1 ITU FREQ CHANNEL Sets the operation wavelength Use the left and right arrow keys to move the cursor and the up and down arrow keys to increment the digits to select the desired ITU channel number range 1 87 for C band model The corresponding frequency and wavelength are displayed Once the val...

Page 14: ...address will be displayed on screen If the request is unsuccessful the address displayed will be the currently stored static IP address If no static IP address has been stored by the user the address displayed will be 0 0 0 0 4 GET STATIC IP Sets the PMDPro for static IP addressing and recalls the static IP address stored in memory See section 4 3 6 for instructions on hardware setup for Ethernet ...

Page 15: ...mation screen Use the ESC key to return to the Setup menu or one of the function keys to access a different menu 4 2 3 PMDE The PMDPro has two operation modes for generating PMD values The discrete mode uses digital switching to generate PMD values according to the lookup table included on the cd 6561 DGD SOPMD pairs can be accessed this way Some of the SOPMD values in this set are wavelength depe...

Page 16: ...0 100 150 200 DGD ps SOPMD ps 2 c d Figure 5 DGD SOPMD coverage plots a 90 ps version discrete mode b 180 ps version discrete mode c 90 ps version quasi continuous mode d 180 ps version quasi continuous mode Pressing the PMDE key on the front panel accesses the PMDPro s DGD PMD generation functions including generation of a single DGD SOPMD pair scanning through DGD or PMD states in the lookup tab...

Page 17: ...states with wavelength independent SOPMD states with wavelength dependent SOPMD The PMD corresponding to the selected index is displayed in the bottom line of the screen The value on the left side is the DGD and the value on the right is the SOPMD The PMD setting is changed in real time as the index is incremented To observe the effect of the generated PMD on the input signal press the MONITOR but...

Page 18: ...le DGD value is determined by whether the PMDPro is a 90 ps or 180 ps unit The maximum available SOPMD value is determined by the DGD value the user selects As the user changes the requested DGD value the maximum available SOPMD value will change accordingly Figure 6 DGD SOPMD range determinants for continuous control Use the left and right arrow keys to move the cursor and the up and down arrow k...

Page 19: ...ulation or execution screens the left arrow key can be used to return to the setting mode the C or E will change back to the symbol and change the requested DGD and SOPMD values To observe the effect of the generated PMD on the input signal press the MONITOR button The display returns to the series of three screens showing respectively the SOP and DOP observed by the input polarimeter before the P...

Page 20: ... the lookup table from lowest index number to highest index number DGD Only scans through a selected subset of the 256 DGD states with SOPMD 0 in order of increasing DGD If DGD Only is selected option a becomes START Scan DGD and option e is enabled c INTERVAL This option allows the user to set the dwell time in ms at each point in the scan The time range is 1 60 000 ms Use the left and right arro...

Page 21: ...0 500 1000 1500 2000 2500 0 20 40 60 80 100 DGD ps SOPMD ps2 Figure 7 Characteristic SOPMD vs DGD curves In the PMD Trace scan function the PMDPro traces out a demi arc of a characteristic curve Each demi arc is half of a characteristic curve with one endpoint on the DGD axis as illustrated in Figure 7 The user selects a particular demi arc to be traced by specifying a DGD value The PMDPro then ma...

Page 22: ...or the selected option a START This option starts the scan Use the other options to perform the scan setup then return to option a to begin the scan While the scan is running the screen displays e MODE BI DIREC f CON RATE _ _1 0 ps s c STEP DIRECTION UP d CYCLES _ _10 Count CYC _ _ _1 10 DIR Å 63 6 ps 2002 7ps2 a START con TRACE b Rng _0 00 64 4 ps A CONTINUOUS TRACE B STEP TRACE CYC number of com...

Page 23: ...n and the ENTER key to select the displayed setting d CYCLES This option sets the number of times to run the scan The cycle number range is 1 9999 Use the left and right arrows to move between digits and the up and down arrows to increment the selected digit The ENTER key sets the number of cycles to the displayed value e MODE This option determines whether one cycle is defined as a single directi...

Page 24: ...p and down arrows to increment the selected digit The minimum step size is 0 1 ps The maximum step size is determined by the range selected in option b The ENTER key selects the displayed value g DWELL time Set the dwell time at each point in ms Use the left and right arrows to move between digits and the up and down arrows to increment the selected digit The dwell time range is 1 to 9999 ms The E...

Page 25: ... AVERAGE DGD 10 0ps e INTERVAL _2000 ms Rng 1 ms to 60000 ms c SAMPLE NUM _ _1000 d CYCLE NUM _ _ _10 A DGD ONLY EMULATION B PMD EMULATION b AVERAGE DGD This option specifies the average DGD value for the Maxwellian distribution Use the left and right arrows to move between digits and the up and down arrows to increment the selected digit The range for average DGD is 0 0 to 45 4 ps for the 90 ps P...

Page 26: ...D emulation are as follows Use the up and down arrows to move between scan setup options and the ENTER key to access the setup screen for the selected option a START This option starts the emulation Use the other options to perform the setup then return to option a to begin generating PMD values During the emulation the screen displays Top line current DGD and SOPMD CY number of completed cycles S...

Page 27: ...e the left and right arrows to move between digits and the up and down arrows to increment the selected digit The range is 1 to 9999 ms The ENTER key selects the displayed value 6 SCAN PMD MEM BANK Scan through a user generated sequence of PMD values There are 5 memory banks labeled A E each with 100 storage locations therefore up to 5 sequences of PMD values can be stored and used for this scan S...

Page 28: ...specifies the beginning memory location for the scan Use the left and right arrows to move between digits and the up and down arrows to increment the selected digit There are 100 memory locations in each bank labeled 00 to 99 As the memory location is changed the right side of the screen displays either the ID corresponding to the PMD stored there for a discrete mode value or Contin for a continuo...

Page 29: ...between digits and the up and down arrows to increment the selected digit The ENTER key sets the number of cycles to the displayed value 4 2 4 SOP Pressing the SOP key accesses the PMDPro s deterministic polarization control and scrambling functions including generation and stabilization of a single SOP specified via Stokes parameters continuous or random scrambling or generation of specified trac...

Page 30: ...0 01 500 Hz for triangle scrambling When the desired frequency is set press the ENTER button The PMDPro will begin scrambling The screen display remains the same but the cursor will move to the bottom right corner of the screen During scrambling pressing the left arrow key will stop the scrambling and move the cursor to frequency selection so that the scrambling frequency can be changed 2 SET SOP ...

Page 31: ...t function that allows the user to simply select one of 6 SOP states commonly used for measurements the 6 Poincaré sphere pole points rather than having to enter the Stokes parameters from the SET SOP screen When this option is selected the LCD displays the following screen a START Selecting option a implements the SOP setting selected in option b The PMDPro will generate and maintain the selected...

Page 32: ... will continue until the user selects another option b TRACE Angle This option allows the user to select the axis about which the great circle will be drawn The axis is a radius of the sphere oriented at a specified angle given in sphere coordinates from the S1 axis 0º The rotation axis is the S1 axis 45º The rotation axis is in the S1 S2 plane midway between the S1 and S2 axes 90º The rotation ax...

Page 33: ...nd down arrow keys to increment the active digit The range is 1 to 60 000 ms The ENTER key selects the displayed option d STEP This option sets the step size in degrees Use the left and right arrow keys to move between digits and the up and down arrow keys to increment the active digit The range is 0 1 to 64 4 The ENTER key selects the displayed option 90º trace 45º trace S3 trace 0º trace 45º tra...

Page 34: ...caré sphere Figure 10 13 show examples of this for each of the 4 channels individually Figure 10 is the trace for a sine wave with amplitude 60V and frequency 5 Hz applied to channel 1 Figure 11 is the same sine wave applied to channel 2 Figure 12 and 13 show the trace for a sine wave with amplitude 30V and frequency 5 Hz applied to channels 3 and 4 respectively Since Vπ is about 30V the first two...

Page 35: ...nel the polarization will switch periodically between two polarization states determined by the amplitude of the wave The frequency determines how long the polarization stays in each state Figure 14 17 show the traces for a square wave with amplitude 30V and frequency 5 Hz applied to channels 1 4 respectively Figure 14 Square wave with A 30V f 5Hz on channel 1 Figure 15 Square wave with A 30V f 5H...

Page 36: ...Figure 18 21 show some examples Figure 18 Sine wave with A 60V f 5Hz on channel 1 Figure 19 Sine wave with A 60V f 5Hz on channel 1 Sine wave with A 60V f 5Hz on channel 2 Sine wave with A 60V f 1Hz on channel 2 Figure 20 Sine wave with A 60V f 5Hz on channel 1 Figure 21 Sine wave with A 60V f 5Hz on channel 1 Sine wave with A 60V f 1Hz on channel 2 Saw wave with A 30V f 3Hz on channel 2 Sine wave...

Page 37: ...re set up for all channels to be used press the ENTER key to begin waveform generation The cursor will move to the lower right of the screen during operation Use the arrow keys to stop operation and return to waveform setup 4 2 5 WSOP After a static PMD state has been set using the PMDE function either from discrete or continuous mode this function uses the PMDPro s polarization controller to adju...

Page 38: ...the DOP of the signal after it passes through the PMD element When WSOP is selected the screen displays 2 options 1 EQUAL POWER SPLIT This option can be used with a DGD only SOPMD 0 discrete mode state PMD ID 0 255 It aligns the polarization state of the signal at the input to the PMD element such that the power is split equally between polarization components aligned to the slow and fast axes of ...

Page 39: ...f the currently selected PMD state The polarization controller will actively optimize SOP as long as the PMDPro is in this mode 4 2 6 PMDC Pressing the PMDC button accesses the PMDPro s PMD compensation functions In this mode the PMDPro uses its polarization controller and PMD generation element to find the optimum SOP and PMD value to compensate for any PMD in the input signal This set of operati...

Page 40: ...surement of the amount of DGD in the system The top line displays the measured DOP at the input I and output O polarimeters The output DOP indicates how well the system PMD is compensated The polarization controller continues to actively optimize SOP as long as the PMDPro is in this mode 2 PMD OPTIMIZED COMP This function scans through all 6561 PMD states in the lookup table including states with ...

Page 41: ... DGD state DGD value and corresponding index number Use the arrow keys to select the desired DGD index The DGD state updates in real time as the index is changed When the desired DGD state is selected press the ENTER key to begin polarization optimization at that state The display format will remain the same but the input and output DOP values in the first line will update with their real time val...

Page 42: ...o optimize a worst case SOP for PMD tolerance testing When the MANUAL key is pressed the LCD displays the following set of screens When the cursor is on the channel selection position cursor blinking on the 1 of V1 for example the arrow keys can be used to move between channels From a channel selection position pressing ENTER will move the cursor to the voltage corresponding to the current channel...

Page 43: ... of the screen indicates the selected storage bank A in this example _Dsc indicates that a discrete mode value is to be stored ID is the PMD index number of the value to be stored the DGD and SOPMD corresponding to the index are displayed in the bottom line of the screen and Lo is the memory location index Use the left and right arrow keys to move the cursor position and the up and down arrow keys...

Page 44: ...cted memory location and increment the memory location by 1 2 PMDC RESULT This option allows the user to store PMD compensation data from any of the PMDPro s PMD compensation functions After obtaining the PMDC result press the STORE button and select the PMDC STORE RESULT option The top line of the screen will display the DOP measured by the input I and output O polarimeters at the end of the last...

Page 45: ...eft corner indicates the selected storage bank A in this example Lo is the memory location index ID is the PMD index number of the value stored at that location the DGD and SOPMD corresponding to the index are displayed in the bottom line of the screen The arrow keys can be used to change the memory location index to look at the contents of other locations If the value stored at a particular locat...

Page 46: ...D compensation run using the PMD or DGD value from the recalled data set 4 3 Remote Control Operation General Photonics provides a control program for the PMDPro which allows access to several advanced functions as well as the basic functions accessible from the front panel The following sections describe the system requirements setup and control program interface 4 3 1 System Requirements Operati...

Page 47: ...The default locations are the ones shown in the screenshot Click Next to proceed A license agreement page will appear Accept the license terms and click Next to proceed A summary page lists the files to be installed or changed Document GP UM PMD 1000 21 Page 47 of 122 ...

Page 48: ... of the files are installed an installation complete screen will be displayed This completes the installation process Click Finish The computer will need to be restarted before the program can be used Document GP UM PMD 1000 21 Page 48 of 122 ...

Page 49: ... 232 connector on the rear panel of the PMDPro is a DB9 male connector Use a straight connection RS 232 cable DB 9 female to female to connect the PMDPro to the RS 232 port of a computer To ensure proper communication use a serial cable with direct pin to pin connected wires see Figure 23 at both ends of the cable 6 7 8 9 1 2 3 4 5 Figure 23 RS 232 connector on rear panel of PMDPro RS 232 command ...

Page 50: ...ISP s DHCP server This is a dynamic IP address Set to an IP address which can be unchanged for months or years at a time This is a static IP address Ethernet Setup 1 Connections There are two connection configurations for Ethernet control a Static IP the administrator assigns the instrument a fixed IP address In this mode the instrument can be directly connected to the control PC as shown in Figur...

Page 51: ...UP button on the front panel GET DYNAMIC IP sets the PMDPro for dynamic IP addressing and requests a dynamic IP address from the server GET STATIC IP sets the PMDPro for static IP addressing and requests the static IP address stored in memory LabView Program The GP_SET_ETHERNET program can also be used to obtain the dynamic IP address or the full set of static IP network settings 3 Set IP address ...

Page 52: ...tion box at the top of the screen The baud rate should be set to 28800 Once these two parameters are set click the white arrow to run the program The program has 3 tabs The first tab GET IP CONFIG is used to query the current IP configuration of the instrument When the Get IP Config button at the left of the screen is clicked the program will read back the instrument s current network parameters a...

Page 53: ...en Dynamic IP mode result The second tab MODE SETTING allows the user to switch the instrument between static and dynamic IP addressing modes Ethernet mode selection screen dynamic Document GP UM PMD 1000 21 Page 53 of 122 ...

Page 54: ...s box will say STATIC The PMDPro writes its most recently saved static IP settings and its active mode to memory If it is powered off while in static mode when it is powered back on it will be in static mode and the most recently saved set of IP configuration information can be used for communication If the PMDPro is powered off while in dynamic IP mode when it is powered back on it will be in dyn...

Page 55: ...r s IP address is 17 the user can set the IP address for the PMDPro to any number in the range 1 254 except 17 Notes To connect the instrument directly to a PC use a PC to PC cable To connect the instrument to a LAN use a standard network cable For Ethernet control the serial port is only used during Ethernet setup via the GP_SET_ETHERNET program The remote control command format is the same for a...

Page 56: ...program before turning off the instrument Monitor Screen When the program is first started if the communication between the computer and PMDPro is properly established the screen shown below will be displayed If the program does not detect the PMDPro it will display a message to that effect Available communication ports will be displayed in a pull down menu at the bottom left of the screen Select ...

Page 57: ...of these buttons is clicked the corresponding operation mode screen appears in the operation area When the program is first started the default operation mode is monitor mode This screen can also be accessed by clicking the MONITOR button in the function selection panel The monitor screen has 4 sections The output power section displays the output power in dBm and mW The DGD SOPMD section displays...

Page 58: ...ues with the total number of samples Sample Num and average DGD in ps specified by the user The range for average DGD is 30 ps for a 90 ps PMDPro and 60 ps for a 180 ps PMDPro Cycle Num is the number of times the scan will be run Scan Interval is the dwell time per point in ms Only DGD states SOPMD 0 are used in the emulation SCAN DGD The PMD 1000 scans a series of DGD values with SOPMD 0 in a use...

Page 59: ...00 scans all DGD SOPMD pairs in order of their index number see lookup table for corresponding values Set the desired dwell time per point Scan Interval and number of times to run the scan Cycle and then click Start to start the scan During the scan the current PMD index number and the corresponding DGD and SOPMD values are displayed Document GP UM PMD 1000 21 Page 59 of 122 ...

Page 60: ...w and fast axes of the PMD element This function can be used only with DGD only states SOPMD 0 These correspond to PMD index numbers 0 255 If a larger index number is selected this function will be disabled The Start Tracking button will be grayed out Click the Start Tracking button to begin the SOP search The DOP values measured by the input and output polarimeters are displayed in the correspond...

Page 61: ...he corresponding Start button to begin scrambling Frequency ranges Random scrambling 1 6000 Hz Triangle scrambling 0 01 500 Hz SET SOP Use this function to set and maintain a particular SOP Set the Stokes parameters of the desired state making sure that they fulfill the condition and then click the Set button to generate and maintain that state 1 2 3 2 2 2 1 S S S In most cases as the user adjusts...

Page 62: ...ull down menu and click Set TRACE SCAN This function traces out a great circle on the Poincaré sphere about the selected axis Select the desired axis from the pull down menu and set the dwell time per point Speed in ms and step size between points in degrees Then click Start to begin generating the trace SCAN ALL traces out one circle about each axis in turn Document GP UM PMD 1000 21 Page 62 of 1...

Page 63: ...ton in this box to begin The PMD 1000 scans through all DGD SOPMD pairs in the lookup table and optimizes the SOP at each point to find the DGD SOPMD pair that best compensates the PMD at the input to the instrument It displays the resulting DGD and SOPMD values as well as the input and output DOP values SELECTED 1st ORDER PMD COMPENSATION Select the desired DGD index number PMD ID and click the S...

Page 64: ... description It can be used to monitor the status of the light signal including the output optical power the current output PMD setting and control mode of the PMD generator and the SOP DOP values at the input and output polarimeters Document GP UM PMD 1000 21 Page 64 of 122 ...

Page 65: ...tion mode allows the user to directly set the control voltages to each channel of the polarization controller rather than using the polarimeter feedback to control the polarization controller The voltage range for each channel is 0 150V Vπ for each channel is about 30V Document GP UM PMD 1000 21 Page 65 of 122 ...

Page 66: ...l screen for the PMD 1000 s deterministic quasi continuous PMD generation function This function allows the user to select any DGD SOPMD combination within the area bounded by the curve The user can select the desired DGD and SOPMD values by dragging the sliders on the plot axes by selecting or typing values in the selection boxes for each axis or by dragging the cursor a red cross to the desired ...

Page 67: ...ests with single polarization signals The PMDPro monitors and displays the DOP values measured by the input and output polarimeters in the boxes above the Enable WSOP button Scan Stored PMD The PMD 1000 has 5 memory banks which can store up to 100 PMD settings each The user can thus store up to 5 sequences of PMD values and then use this function to scan through them Select the desired memory bank...

Page 68: ...erated and its DGD and SOPMD values are displayed above the graph PMD Emulation This function performs statistical first order or first and second order PMD emulation to simulate the PMD in real systems For single polarization signals the SOP can also be automatically optimized for worst case PMD effect at each PMD value Select DGD only SOPMD 0 or PMD DGD SOPMD emulation from the pull down menu at...

Page 69: ...erated Random DGD values are generated in random order Sorted DGD values are generated in increasing order from lowest to highest Interval dwell time in s per sample Minimum value is 0 001s However data will only be plotted for dwell times 1s Cycle Num Number of times to run the scan The DGD distribution plot shows the calculated distribution of DGD values that corresponds to the selected paramete...

Page 70: ...rated points For dwell time values 1 s the WSOP function is also available Click the WSOP Enable button at the bottom left of the screen before starting the emulation to enable automatic polarization optimization for the worst case PMD effect at each DGD value Please note that the WSOP function is only effective for single polarization signals For dwell time values 1 s the WSOP and scan monitoring...

Page 71: ...within the distribution will be generated Random DGD values are generated in random order Sorted DGD values are generated in order from lowest to highest Interval dwell time in s per sample Minimum value is 0 001s However data will only be plotted for dwell times 1s Cycle Num Number of times to run the scan The plots in the top row show the calculated distributions of values for the emulation The ...

Page 72: ...t of the screen shows the DGD and SOPMD sample number number of completed cycles and input and output DOP The generated PMD DGD and SOPMD distribution plots track the progress of the emulation When the emulation is complete the generated value plots will match the calculated value plots above them For dwell time values 1 s the WSOP function is also available Click the WSOP Enable button at the bot...

Page 73: ...e generated As each trace is configured it is added to the trace list in the upper left corner of the screen and to the graph on the right side of the screen To add a trace to the list go to the trace setting block in the middle left of the screen Select a DGD value in the Start DGD box This is the trace endpoint on the DGD axis with SOPMD 0 The DGD and SOPMD values corresponding to the other endp...

Page 74: ...r selectable DGD step size and dwell time at each point The transient between any two consecutive points on a trace still follows the trace however so either the continuous or step scan can be used for applications that require continuous PMD variation The step direction pull down menu selects the direction of travel along the trace If UP is selected the PMDPro starts at the lower DGD limit point ...

Page 75: ...s between consecutive points and the dwell time is the time in seconds that the PMDPro stays on each point The step size range is 0 1 to 64 ps and the dwell time range is 0 001 to 9 999s Once the trace list and scan operation parameters are configured click the Start button to begin The monitor block on the right of the screen shows the progress of the scan The cursor will move along the traces as...

Page 76: ...t DGD DGD start value in ps Stop DGD DGD end value in ps DGD step step size in ps Fixed SOPMD fixed SOPMD value in ps2 Scan Interval on top of graph dwell time per point in s Minimum value 0 4 s Note that the SOPMD value setting may limit the DGD scan range When the scan parameters are set click Start to start the scan As each point is generated the DGD SOPMD and output DOP are displayed above the...

Page 77: ... defined SOPMD range with a fixed DGD value Selection parameters Fixed DGD fixed DGD value in ps Start SOPMD SOPMD start value in ps2 Stop SOPMD SOPMD end value in ps2 SOPMD step step size in ps2 Scan Interval on top of graph dwell time per point in s Minimum value 0 4 s Document GP UM PMD 1000 21 Page 77 of 122 ...

Page 78: ...nd step sizes Selection parameters Start DGD DGD start value in ps Stop DGD DGD end value in ps DGD step DGD step size in ps Start SOPMD SOPMD start value in ps2 Stop SOPMD SOPMD end value in ps2 SOPMD step SOPMD step size in ps2 Scan Interval on top of graph dwell time per point in s Minimum value 0 4 s When the scan parameters are set click Start to start the scan As each point is generated the ...

Page 79: ... in s should be set in the box above the graph The minimum value is 0 4 s When all of the PMD values are entered into the table click Start to start the scan As each point is generated the DGD SOPMD and output DOP are displayed above the graph and the output DOP vs DGD is plotted in the graph on the left The graph on the right is a 3D graph of DOP vs SOPMD and DGD It can be rotated or zoomed for v...

Page 80: ...tem That PMD value is the measured PMD for the system under test There are two tabs under this function set PMD Measurement This function uses the quasi continuous PMD generation mode to scan through a selected set of PMD values and optimize the SOP at each state in the scan to maximize the output DOP It allows the user to scan through a selected DGD range with fixed SOPMD or a selected SOPMD rang...

Page 81: ...scan parameters are set click Start to start the scan At each point in the scan the DGD SOPMD and maximum output DOP for that point are displayed above the graphs and the maximum output DOP vs DGD is plotted in the graph on the left The maximum output DOP for the scan and the corresponding DGD and SOPMD values are displayed below the graph After the scan is finished the data can be saved to a file...

Page 82: ... the scan parameters are set click Start to start the scan At each point in the scan the DGD SOPMD and maximum output DOP for that point are displayed above the graphs and the maximum output DOP vs SOPMD is plotted in the graph on the left The maximum output DOP for the scan and the corresponding DGD and SOPMD values are displayed below the graph After the scan is finished the data can be saved to...

Page 83: ...DGD SOPMD and maximum output DOP for that point are displayed above the graphs and the maximum output DOP vs DGD is plotted in the graph on the left The maximum output DOP for the scan and the corresponding DGD and SOPMD values are displayed below the graph The graph on the right is a 3D graph of DOP vs SOPMD and DGD It can be rotated or zoomed for viewing from different perspectives To rotate a 3...

Page 84: ...rt to start the scan At each point in the scan the DGD SOPMD and maximum output DOP for that point are displayed above the graphs and the maximum output DOP vs DGD is plotted in the graph on the left The maximum output DOP for the scan and the corresponding DGD and SOPMD values are displayed below the graph The graph on the right is a 3D graph of DOP vs SOPMD and DGD It can be rotated or zoomed fo...

Page 85: ...the maximum output DOP vs DGD is plotted in the graph The DGD value with the highest output DOP is displayed in the Measured DGD box at the top of the screen The graph serves as a measurement of both the PMD in the system and of how much of an effect PMD compensation will have The DGD value corresponding to the peak DOP in the plot is the DGD in the input signal to the PMD 1000 The height of the p...

Page 86: ...emulator Figure 26 illustrates a system setup for PMD monitoring using General Photonics Tunable Channelized ASE Source TCA 1000 in conjunction with the PMDPro The TCA 1000 is used as the input to one frequency channel before multiplexing After demultiplexing that frequency channel is sent to the PMDPro which performs DGD measurements at user specified intervals Since the PMD effect varies with in...

Page 87: ...requency in THz of the signal to be measured As this value is updated the corresponding wavelength in nm will be displayed in the box immediately below the frequency box Once the setup is complete click Start to begin recording data The PMDPro will perform PMD measurements at the specified time intervals After each measurement is complete the PMDPro will record the following data to the file optic...

Page 88: ...discrete mode lookup table Setup This screen allows the user to set the basic operation parameters for the PMD 1000 Setup parameters Operation Wavelength First select the wavelength band e g C or L band Then select the ITU grid channel number The indicator boxes will display the corresponding frequency in THz and wavelength in nm of the selected channel The wavelength setting updates in real time ...

Page 89: ... Number Memory location index number Discrete Continuous 1 0 Indicates whether a discrete or a continuous mode PMD value is to be stored at that location 1 Discrete lookup table value 0 Continuous PMD value PMD ID If a discrete value is to be stored at the current location type in the index number of the desired DGD SOPMD pair from the lookup table Index number range is 0 6560 For a discrete value...

Page 90: ...the data in the table on the right Export After stored data is recalled to the table on screen it can be exported to a text file by clicking the EXPORT button The program will prompt for a file name and location Data is stored in the format in which it is displayed in the on screen table Import Data previously exported to a text file can be imported by clicking the IMPORT button The program will p...

Page 91: ... measurement and store the results to the selected location The indicator boxes immediately below the Memory Loc ID box will display the data DGD SOPMD input and output DOP after the measurement is completed Recall PMD measurement results from memory To recall stored PMD measurement results and display them in the table on screen specify the range of memory locations to be queried by selecting the...

Page 92: ... DGD range of the PMD 1000 90 or 180 ps PMD ID index number for the PMD setting to be used for simulation Start WL starting wavelength in nm to be used for simulation Stop WL ending wavelength in nm to be used for simulation Step wavelength step in nm to be used for simulation Once the parameters for the simulation are selected click Calculate to run the simulation Click SET PMD to execute the set...

Page 93: ...crete mode PMD query Query current or most recently set PMD ID Range 0 to 6560 Example 1005 If not in PMD mode will return the last PMD ID set PMD CON CAL Continuous mode PMD query Query most recent set of calculated DGD SOPMD values dgd sopmd Eg 30 37 100 0 DGD given in ps SOPMD in ps2 PMD CON MAX Continuous mode PMD query Queries 1 DGD range of PMDPro and 2 maximum SOPMD available with the DGD c...

Page 94: ...in Continuous Trace Scan using current settings E00 if successful See Table 2 for other error code definitions PME SCN CON DIS Disable stop Continuous Trace Scan E00 if successful See Table 2 for other error code definitions PME SCN STE ENA Begin Step Trace Scan using current settings E00 if successful See Table 2 for other error code definitions PME SCN STE DIS Disable stop Step Trace Scan E00 if...

Page 95: ... D or E E00 if successful See Table 2 for other error code definitions PME SCN TYP bnk mn mx Query whether Location Range mn to mx of Memory Bank bnk contains only one type discrete lookup table or continuous of PMD values or a mixture of types MIX Range contains both discrete and continuous PMD values UNI Range contains only discrete or only continuous PMD values PME SCN DIS Stop Scan Discrete mo...

Page 96: ... in ms SOP CONTROL MODE SOP RAN ENA Begin enable random scrambling E00 if successful See Table 2 for other error code definitions SOP RAN DIS Stop disable random scrambling E00 if successful See Table 2 for other error code definitions SOP RAN FRQ Query random scrambling frequency setting 123 Results are in Hz SOP RAN FRQ frq Set frequency for random scrambling in Hz Range 1 to 6000 E00 if success...

Page 97: ... scan step size setting Ex 99 9 SOP TRA STA Query the SOP trace scan axis setting 0 45 45 90 S3 0 ALL SOP TRA 0 SOP TRA 45 SOP TRA 45 SOP TRA 90 SOP TRA S3 0 SOP TRA ALL Set trace scan axis 0 45 45 90 S3 0 Trace equator of Poincaré sphere All Perform all 5 traces sequentially Set the trace scan axis E00 if successful See Table 2 for other error code definitions WAVEFORM MODE SOP MPC ENA Begin enab...

Page 98: ... on minimum output DOP Valid for any PMD setting PMD setting used is the most recently set discrete or continuous PMD value E00 if successful See Table 2 for other error code definitions WSP DIS Stop disable automatic worst case SOP control E00 if successful See Table 2 for other error code definitions MONITOR MODE MON PMD Query current or most recent PMD setting Units DGD ps 2nd order PMD ps2 Ret...

Page 99: ...ful See Table 2 for other error code definitions MEMORY MODE SAV DSC MBX loc id Discrete mode PMD sequence storage Store PMD ID id to memory location loc in memory Bank X Range for loc 0 to 99 Range for id 0 to 6560 Range for X A B C D or E Example SAV DSC MBE 02 36 Save PMD ID 36 to memory location 02 in Bank E SAV CON MBX loc dgd so Continuous mode PMD sequence storage Store DGD value dgd in ps ...

Page 100: ...ro configuration ordered ADR adr Set GPIB address Range 1 to 30 E00 if successful See Table 2 for other error code definitions Example ADR 5 ADR Query GPIB address Return 30 Set Ethernet Mode and Query IP Address Note This set of commands must be sent from RS 232 only 7DHCP Set instrument to dynamic IP mode OK 6STIP Set instrument to static IP mode OK 8IP Request IP address Note Returns either dyn...

Page 101: ...exed signals Front Panel Control 1 Set the PMD value Press the PMDE button to bring up the PMD generation menu Select either option 1 SET DISCRETE PMD or option 2 SET CONTINUOUS PMD 2 For discrete mode use the arrow buttons to select the index number corresponding to the desired DGD SOPMD pair The DGD SOPMD values will be updated in real time as the index numbers are changed The continuous mode ed...

Page 102: ...late the closest available matches to the requested values If the requested SOPMD is out of range the PMDPro will flash an SOPMD out of range error message before returning to the PMD selection screen If the selected values are within range the LCD will display where the number to the right of the C on each line is now the calculated match to the requested value At this point the PMDPro has not ye...

Page 103: ...ange is 0 01 500 Hz After the frequency is set press the ENTER button to begin scrambling The cursor will move to the bottom right of the screen while scrambling is enabled Pressing the left arrow key will disable the scrambling and move the cursor back to frequency selection Control Program The setup process using the control program is similar to that using the front panel See the remote control...

Page 104: ...er is updated and the output PMD updates in real time 3 Click the SOP button on the left function panel to bring up the polarization control interface screen 4 Select a frequency in the triangle scrambling section at the top left of the screen and click the Start button to begin scrambling Document GP UM PMD 1000 21 Page 104 of 122 ...

Page 105: ...either selecting a value from the pull down menu or typing a value in the box under the pull down menu and clicking elsewhere on the screen Then click Enable Scrambling 5 2 PMD Mitigation in 40Gb s systems As the bit rate of fiber optic communication systems increases from 10 Gbps to 40Gbps 100 Gbps and beyond polarization mode dispersion PMD has more and more impact on system performance PMD gene...

Page 106: ...ble fiber routes to identify and cherry pick those with sufficiently low PMD However such an approach has three potential drawbacks First the PMD of a fiber route changes with time as the environmental conditions around the fiber change Such changes can include land movements caused by earthquake flood or mud slides A route that is good today may become bad in the future Second interconnected fibe...

Page 107: ...D generated by the PMD generating device is the same in value as that of the fiber link but with its slow axis aligned with the fast axis of the fiber link PMD Figure 30 Optical PMD compensation The DOP measured by the polarimeter is used as PMD effect indicator The final approach is polarization multiplexed coherent detection Because the detected information of the corresponding optical signal an...

Page 108: ...asured and plotted as shown in Figure 31C The system outage probability can be calculated from the data obtained Figure 31 A PMD tolerance test setup using a PMD source The computer selects PMD settings and collects BER readings B BER vs DGD curve The DGD tolerance of the system for a given BER threshold can be deduced using the curve C Map of BER vs DGD and SOPMD Each contour represents a BER val...

Page 109: ...e of the medium γ is the power distribution ratio of the two polarization components with respect to the principal state of polarization PSP of the DGD element γ when the powers of the two polarization components are equal or when the input SOP to the medium is oriented 45 degrees from its PSP and τ R is the self correlation function of the optical signal which decreases as τ increases Clearly the...

Page 110: ...e compensator may be inside the receiver RX The plots shown in Figure 31 can be generated here with PMD compensation at different PMD settings of the PMD source PMD analyzer or monitor for link PMD determination The PMD values of fiber routes generally must be measured before link deployment This requires PMD analyzers In general a PMD analyzer requires a large bandwidth light source whether it is...

Page 111: ... fiber link because the PMD value used for optimal PMD compensation is close to the real PMD value of the fiber link Such a feature is attractive for frequent PMD monitoring of an in service fiber link a task that cannot be accomplished with PMD analyzers currently on the market 5 5 The polarization optimized PMD source The PMDPro meets all of the requirements described above It is constructed wit...

Page 112: ... polarization rotator sandwiched between each pair of adjacent crystal segments as shown in Figure 34 The crystals are arranged in descending order with lengths decreasing sequentially by a factor of 2 Each rotator is capable of rotating the state of polarization SOP by 45 0 or 45 degrees Rotator 1 Rotator 2 Rotator N Birefringent Crystals Figure 34 The construction of a PMD generator made with bi...

Page 113: ...alog crystal rotators used in other PMD source designs which suffer from slow speed and low repeatability the digital ternary operation method of this PMD source makes PMD generation fast and highly repeatable In addition to the digital ternary rotators described above the PMDPro uses a quasi continuous rotator to achieve independent DGD and SOPMD control allowing it to uniformly cover the PMD spa...

Page 114: ...either an automatically optimized PMD value or a user selected PMD value The PMD compensation is accomplished by maximizing the DOP detected by the polarimeter at the output port Both PMD and DOP values will be shown on the front panel LCD display By stepping the PMD values up and down and looking at the maximized DOP values the user can directly see how the PMD value chosen affects PMD compensati...

Page 115: ...n The PMD generator can generate statistical PMD distributions to emulate PMD variations in fiber systems 8 Polarization control functions Using its built in polarization controller and polarimeters this instrument can perform all polarization control functions including deterministic SOP generation polarization scrambling and polarization trace generation It can therefore be used as a general pur...

Page 116: ...dden increase in loss 1 Make sure that no sudden external force or vibration was applied to the instrument 2 Use the DGD or PMD scan function to find out how many states are out of order This information indicates the possibility of damage to the optical components inside the device 3 If the problem persists the control circuit of the module may have been damaged D Front panel static Ethernet setu...

Page 117: ...please contact General Photonics Corporation at 909 590 5473 telephone or 909 902 5536 fax or by e mail at support generalphotonics com General Photonics will respond to all customer questions within 24 hours during regular business hours General Photonics can also be contacted by mail at General Photonics 5228 Edison Avenue Chino California 91710 USA Document GP UM PMD 1000 21 Page 117 of 122 ...

Page 118: ...2 C10 192050 1561 01 C11 192100 1560 61 C12 192150 1560 20 C13 192200 1559 79 C14 192250 1559 39 C15 192300 1558 98 C16 192350 1558 58 C17 192400 1558 17 C18 192450 1557 77 C19 192500 1557 36 C20 192550 1556 96 C21 192600 1556 55 C22 192650 1556 15 C23 192700 1555 75 C24 192750 1555 34 C25 192800 1554 94 C26 192850 1554 54 C27 192900 1554 13 C28 192950 1553 73 C29 193000 1553 33 C30 193050 1552 93...

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