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DETECTOR CHARACTERISTICS

17

Fig 3. Responsivity vs. wavelength for a) Models 100X and b) Models
101X and 102X.

0.0

0.2

0.4

Responsivity
increases
from 0–0.42 A/W
over the range of
950–970 nm.

Wavelength, nm

400

600

800

1000

1200

1400

1600

1800

Responsivity, A/W

a

b

Summary of Contents for 100X

Page 1: ...Models 100X 101X 102X USER S MANUAL F I B E R C O U P L E D U L T R A H I G H S P E E D P H O T O D E T E C T O R M O D U L E S ...

Page 2: ...ART The Models 101X and 102X are high speed InGaAs photodetector modules for detection of light of wavelengths 950 to 1650 nm The Models 100X are GaAs photodetector modules for detection of light of wavelengths 400 to 900 nm All are 50 Ω terminated except the 1001 and 1004 which have 100 Ω terminations An internal battery and bias circuitry make the modules self contained so that no additional pow...

Page 3: ...our measurement instrument being careful not to over torque the K connector The instrument must have a 50 Ω input impedance 8 Check that the optical power emerging from your fiber is below the Max Pulse Power or cw Saturation Power as appropriate see the Detector Characteristics section of this manual to ensure detector linearity and to avoid detector damage 9 Connect your optical fiber to the con...

Page 4: ... due to overvoltage New Focus offers a total of eight models allowing you to match your wavelength of interest and the connector style of your instru mentation The Models 101X and 102X are high speed InGaAs photodetector modules for detection of light of wavelengths 950 to 1650 nm Models 101X are optimized for a flat frequency response and the Models 102X are optimized for an impulse response with...

Page 5: ...hout an optical input this voltage is the DC offset plus dark current This dark voltage should be less than 10 mV 5 If needed keep the voltmeter connected to the module while you optimize coupling to the fiber Making the Microwave Connection Connect the microwave output connector of the photodetector module to a 50 Ω input test instrument such as an oscilloscope or spectrum analyzer or other 50 Ω ...

Page 6: ...use the Model 9854 Opti Claw or the Model 9016 tiny fiber positioner 2 Measure the power in the fiber prior to connection to the module to be sure it is within the safe operating range see the Detector Characteristics section of this manual The Models 20X1 FC and 20X1 ST photoreceivers are useful for this purpose and have the sensitivity to aid in fiber alignment 3 Connect the fiber optic cable to...

Page 7: ...ers for 1014 1024 600 to 900 nm wavelength Model 1223 pigtail FC assembly 2 meters for 1004 1006 1 1 to 1 6 µm wavelength Model 1232 pigtail FC assembly 2 meters for 1014 1024 1 1 to 1 6 µm wavelength Model 1222 ST FC 2 meters These assemblies are available from New Focus Collimators require an Opti Claw tilt mount such as the Model 9854 Pigtail assemblies require a fiber aligner such as the Model...

Page 8: ...When depressed bias voltage is applied to bias monitor port 2 00 50 8 Remove two screws to replace 9V battery 2 00 50 8 3 27 82 9 2 25 57 1 Bias monitor port Output is equal to photodiode current times 1000 ohms for one millivolt per microamp Shown with output K connector 1001 K connector 1002 V connector 1004 K connector 1006 V connector 1011 K connector 1014 K connector 1021 K connector 1024 K c...

Page 9: ... can be eliminated by using a fiber with a core small enough that only a single mode will propagate In this case the bandwidth of the fiber will be limited by material dispersion which is a property of the glass used in the fiber core In this limit the bandwidth is approximately ƒ3 dB 1 2LM λ where L is the fiber length in kilometers M is the material dispersion in ps nm km and λ is the line width...

Page 10: ...xial cable is not used performance can be degraded if an improper adapter is chosen for mating to the instrument Common SMA connectors for example are intended for use to only 18 GHz Table 2 is a list of a few connectors and the frequency range in which they may be used Table 2 Common RF connectors and the corresponding frequency ranges in which they are useful Connector Type Frequency Range Compa...

Page 11: ...he microwave housing with a 0 2 meter 9 µm core fiber Although the material and modal dispersion per unit length of this fiber can be high at certain wavelengths there is no degradation in frequency response since the fiber is less than 0 2 meters long The fiber is protected by a sheet metal flange to prevent damage while changing the battery A simplified schematic is provided in Fig 2 for your re...

Page 12: ...APPENDICES 12 Fig 2b Simplified schematic diagram of the 101X and 102X series photodetector modules Microwave Housing Photodiode Microwave Output Connector V V V V V On Off Batt Chk Bias Monitor V V ...

Page 13: ...n apparent degradation of responsivity See Basic Optical Test below Test Procedures and Solutions DC Offset Voltage With no light on the photodetector turn the detector on and use a voltmeter to measure the Bias Monitor output voltage This voltage is the DC offset plus dark current If the output is 10 mV then the detector is probably damaged and will need to be returned to New Focus Checking the B...

Page 14: ... light into the photodetector 4 With the voltmeter or oscilloscope you should observe a DC output voltage If you know the optical power and wavelength you can calculate the expected output voltage Vout using the expression Vout Pin R G where Pin is the input optical power watts R is the photodetector s responsivity A W and G is the amplifier s transimpedance gain V A The gain of the bias monitor p...

Page 15: ...h a Phillips screwdriver Remove the back panel 5 Remove the two screws on the bottom of the detector using an Allen key 1 16 or 1 5 mm and carefully slide the detector housing off Steps 6 8 Be extremely careful not to pull on the fiber Stress applied to the fiber where it attaches to the microwave hous ing can cause the fiber to misalign from the photodiode resulting in degraded detector performan...

Page 16: ...Hz 90 pW Hz 45 pW Hz 45 pW Hz cw Saturation Power 5 mW 5 mW 1 mW 1 mW Max Pulse Power 200 mW 200 mW 100 mW 100 mW Detector Material GaAs GaAs InGaAs InGaAs Detector Type Schottky Schottky Schottky Schottky Detector Diameter 12 µm 12 µm 12 µm 12 µm Power Requirements 9 V battery 9 V battery 9 V battery 9 V battery Optical Input single mode fiber ST FC ST FC ST FC ST FC Electrical Output Wiltron K W...

Page 17: ...Fig 3 Responsivity vs wavelength for a Models 100X and b Models 101X and 102X 0 0 0 2 0 4 Responsivity increases from 0 0 42 A W over the range of 950 970 nm Wavelength nm 400 600 800 1000 1200 1400 1600 1800 Responsivity A W a b ...

Page 18: ...or malfunctions or becomes damaged please contact New Focus for a return authorization number and instructions on shipping the unit back for evaluation and repair Information and advice about the operation of any New Focus product is available from our technical support engineers For technical assistance or to discuss a repair you can reach us at NEW FOCUS Inc Phone 408 980 8088 2630 Walsh Avenue ...

Page 19: ... START 2 INTRODUCTION 4 OPERATION 5 APPENDIX 1 USING AN OPTICAL FIBER 9 APPENDIX 2 USING THE CORRECT MICROWAVE CONNECTOR 10 APPENDIX 3 INSIDE THE PHOTODETECTOR MODULE 11 TROUBLESHOOTING 13 DETECTOR CHARACTERISTICS 16 WARRANTY SERVICE SUPPORT 18 19 ...

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