THORLABS 24-00245-02, User Manual

Page 1: ...DET08CFC M Fiber Input InGaAs Biased Detector User Guide ...

Page 2: ...4 4 Dark Current 6 4 5 Junction Capacitance 7 4 6 Bandwidth and Response 7 4 7 Terminating Resistance 8 4 8 Shunt Resistance 8 4 9 Series Resistance 8 4 10 Damage Threshold 8 4 11 Battery Replacement 9 Chapter 5 Common Operating Circuits 10 Chapter 6 Specifications 12 6 1 Response Curve 13 6 2 Typical Response 13 6 3 Mechanical Drawing 14 Chapter 7 Troubleshooting 15 Chapter 8 Certificate of Confo...

Page 3: ...ion Direct Current Alternating Current Both Direct and Alternating Current Earth Ground Terminal Protective Conductor Terminal Frame or Chassis Terminal Equipotentiality On Supply Off Supply In Position of a Bi Stable Push Control Out Position of a Bi Stable Push Control Caution Risk of Electric Shock Caution Hot Surface Caution Risk of Danger Warning Laser Radiation Caution Spinning Blades May Ca...

Page 4: ...PC bulkhead connector detector and 12 V bias battery enclosed in a compact aluminum housing The FC PC connector provides easy coupling to fiber based light sources The output uses an SMA jack to minimize size and maximize frequency response The maximum bandwidth is 5 GHz and will operate over the spectral range of 800 1700 nm A visible version the DET025AFC M is also available for operation in the...

Page 5: ...om and side of the housing and mount into a PH series post holder 2 Attach a 50 Ω SMA to Coax cable i e CA28xx to the output of the detector Select and provide a terminating resistor to the remaining end of the cable See Chapter 4 page 5 to determine resistor values Thorlabs sells a 50 Ω terminator T4119 for best frequency performance and a variable terminator VT1 for output voltage flexibility No...

Page 6: ... light Depicted in Figure 1 is a junction photodiode model with basic discrete components to help visualize the main characteristics and gain a better understanding of the operation of Thorlabs photodiodes Figure 1 Photodiode Model 4 2 Responsivity The definition of photodiode responsivity is the ratio of generated photocurrent IPD to the incident light power P at a given wavelength 4 3 Modes of O...

Page 7: ...of the device is restricted causing a build up of voltage This mode of operation exploits the photovoltaic effect which is the basis for solar cells When operating in photovoltaic mode the amount of dark current is at a minimum setting 4 4 Dark Current When a bias voltage is applied to a photodiode a leakage current called dark current is produced Photoconductive mode tends to generate a higher da...

Page 8: ...e s bandwidth and response It reaffirms that larger diode areas encompass a greater junction volume with increased charge capacity In a reverse bias application the depletion width of the junction increases thus effectively reducing the junction capacitance and increasing the response speed 4 6 Bandwidth and Response A load resistor will react with the photodetector junction capacitance to limit t...

Page 9: ... on the photodiode material For example and InGaAs detector has a shunt resistance on the order of 10 MΩ while a Ge detector is in the kΩ range This can significantly affect the noise current on the photodiode For most applications however the high resistance produces little effect and can be ignored 4 9 Series Resistance Series resistance models the resistance of the semiconductor material This r...

Page 10: ...5 mW light source at peak wavelength When no light is applied the supply current is very small and the battery hardly degrades Locate the battery cap directly above the output BNC Unthread the cap and remove the battery Install the new battery into the cap negative side in and thread the cap back into the detector Be careful not to cross thread the cap into the housing This detector does not inclu...

Page 11: ...based upon the incident light and its wavelength and can be viewed on an oscilloscope by attaching a load resistance on the output of the detector The RC Filter removes all high frequency noise from the input supply which otherwise may contribute to a noisy output Figure 3 Amplified Detector On Off Switch Protection Diode Photodetector VBAT RC Filter External Resistor 1 kΩ Capacitor 0 1 µF V Bias ...

Page 12: ...todiode holding point A at the same potential as point B by the operational amplifier This eliminates the possibility of dark current Photoconductive Mode The photodiode is reverse biased improving the bandwidth while lowering the junction capacitance The gain of the detector is dependent on the feedback element RF The bandwidth of the detector can be calculated using the following equation 3 4 Wh...

Page 13: ...V After Pulse Ringing 20 of Maximum Bias Voltage VR 12 V Dark Current b ID 1 5 nA Output Voltage VOUT 0 to 1 V 50 Ω c General Input FC PC Fiber Connector Output SMA DC Coupled Package Size 2 21 x 1 40 x 0 80 56 1 mm x 35 6 mm x 20 3 mm Ball Lens Diameter 0 059 1 50 mm Ball Lens Clear Aperture 0 8 mm Weight 0 18 kg Storage Temp 0 to 40 C Operating Temp 0 to 40 C Battery A23 12 VDC 40 mAh Replacemen...

Page 14: ...DET08CFC M Page 13 Rev B April 29 2015 6 1 Response Curve 6 2 Typical Response Figure 4 Tr 55 ps Tf 52 ps 20 80 Tp 110 ps ...

Page 15: ...0 35 6 mm 0 95 24 1 mm 2 23 56 6 mm 0 80 20 3 mm 0 95 25 1 mm 0 40 10 2 mm 0 35 8 9 mm 0 40 10 2 mm 0 40 10 2 mm 1 50 38 1 mm 0 40 10 2 mm Mounting Hole 8 32 M4 x 0 25 SMA Female Output Connector Battery Tube Use Only A23 12 V Batteries FC PC Fiber Input Connector InGaAs Photodetector ...

Page 16: ...light and verify that a 60 Hz 50 Hz outside the US signal appears on the scope If so the device should be operating properly and the problem may be with the light source or alignment There is an AC signal present when the unit is turned off The detector has an AC path to ground even with the switch in the OFF position It is normal to see an output response to an AC signal with the switch in this s...

Page 17: ...DET08CFC M Chapter 8 Certificate of Conformance TTN020103 D02 Page 16 Chapter 8 Certificate of Conformance ...

Page 18: ...uch as Pure OEM products that means assemblies to be built into a unit by the user e g OEM laser driver cards Components Mechanics and optics Left over parts of units disassembled by the user PCB s housings etc If you wish to return a Thorlabs unit for waste recovery please contact Thorlabs or your nearest dealer for further information 9 1 Waste Treatment is Your Own Responsibility If you do not ...

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