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Chapter 3: Setup 

13124-S01 

Page 4

 

Chapter 3  Setup 

The detector can be set up in many different ways using our extensive line of 
adapters. However, the detector should always be mounted and secured for best 
operation. Step 1 in the setup instructions below outline how to mount the 
detector onto a post. 

1.  Unpack the optical head, install a Thorlabs TR-series ½" diameter post into 

one of the #8-32 (M4 on /M version) tapped holes, located on the bottom 
and side of the sensor, and mount into a PH-series post holder.  

2. Attach 

50 

 coax cable (i.e. RG-58U) to the output of the DET. Select and 

install a terminating resistor to the remaining end of the cable and connect to 
a voltage measurement device. See Chapter 4, page 5to determine resistor 
values. Thorlabs sells a 50 

 terminator (T4119) for best frequency 

performance and a variable terminator (VT1) for output voltage flexibility. 
Note the input impedance of your measurement device since this will act as 
a terminating resistor. A load resistor is not necessary when using current 
measurement devices. 

3.  Power the DET on using the power switch. To check battery voltage, see the 

Battery Check section on page 8. 

4.  Install any desired filters, optics, adapters, or fiber adapters to the input 

aperture.  

Caution! 

The DET50B was designed to allow maximum accessibility to the 

photodetector by having the front surface of the diode flush with the 

outside of the DET housing. When using fiber adapters, make sure that the 

fiber ferrule does not crash into the detector. Failure to do so may cause 

damage to the diode and or the fiber. An easy way to accomplish this is to 

install a SM1RR retaining ring (included with the DET50B) inside the 1" 

threaded coupler before installing the fiber adapter 

5.  Apply a light source to the detector. 

 

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Summary of Contents for DET50B

Page 1: ...DET50B Ge Biased Detector User Guide...

Page 2: ...rk 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 Battery Check 8 4 11 Battery Replacement 9 Chapter...

Page 3: ...ct 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...

Page 4: ...ight signals over 800 to 1800 nm range The unit comes complete with a photodiode and internal 12 V bias battery enclosed in rugged aluminum housing The DET50B includes a removable 1 optical coupler SM...

Page 5: ...best frequency performance and a variable terminator VT1 for output voltage flexibility Note the input impedance of your measurement device since this will act as a terminating resistor A load resisto...

Page 6: ...ased upon the incident 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 operat...

Page 7: ...ero biased The flow of current out of the device is restricted and a voltage builds up This mode of operation exploits the photovoltaic effect which is the basis for solar cells The amount of dark cur...

Page 8: ...dwidth and the response of a photodiode It should be noted that larger diode areas encompass a greater junction volume with increased charge capacity In a reverse bias application the depletion width...

Page 9: ...example and InGaAs detector has a shunt resistance on the order of 10 M while a Ge detector is in the k range This can significantly impact the noise current on the photodiode For most applications h...

Page 10: ...ach DET with an A23 12 V battery installed This battery is readily available at most retail stores as well as through Thorlabs The battery supplied will deliver about 40 hours with a 1 mA load roughly...

Page 11: ...ed upon the incident light and wavelength and can be viewed on the oscilloscope by attaching a load resistance on the output The function of the RC Filter is to filter any high frequency noise from th...

Page 12: ...diode since point A is held at the same potential as point B by the operational amplifier This eliminates the possibility of dark current Photoconductive mode The photodiode is reversed biased thus im...

Page 13: ...e a 10 M input impedance Point the detector toward a fluorescent 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 pr...

Page 14: ...D 40 A Output Voltage VOUT 0 to 5 V General On Off Switch Slide Battery Check Switch Momentary Pushbutton Output BNC DC Coupled Package Size 2 8 x 1 9 x 0 83 70 mm x 48 mm x 21 mm PD Surface Depth 0 1...

Page 15: ...Chapter 7 Specifications 13124 S01 Page 14 7 1 Response Curve...

Page 16: ...5 Thread M4 x 6 35mm for EC 26 2 mm 1 03 in 19 1 mm 0 75 in 16 2 mm 0 64 in 48 0 mm 1 89 in 53 3 mm 2 10 in 70 1 mm 2 76 in 43 2 mm 1 70 in Battery Position Indicator Power Switch A Battery Cap Output...

Page 17: ...Chapter 8 Certificate of Conformance 13124 S01 Page 16 Chapter 8 Certificate of Conformance...

Page 18: ...such 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...

Page 19: ...654444 www thorlabs com Email sales uk thorlabs com Support techsupport uk thorlabs com France Thorlabs SAS 109 rue des C tes 78600 Maisons Laffitte France Tel 33 0 970 444 844 Fax 33 0 825 744 800 w...

Page 20: ...www w thorlabs c com...

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