Chapter 3 Setup - THORLABS DET20C2 User Manual

InGaAs Biased Detector

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 either an imperial or metric optical post into
one of the mounting holes located on the bottom and side of the sensor, and
mount using a post holder. Note that these detectors feature tapped holes
that accept both 8-32 and M4 threads, so using either imperial or metric TR
posts is possible.
Attach a 50 Ω coax cable (i.e. RG-58U) to the output of the DET. Select and
2.
install a terminating resistor to the remaining end of the cable and connect to
a voltage measurement device. See Error! Reference source not found.,
page 7 to determine resistor values. Thorlabs sells a 50 Ω terminator
(T4119) for best frequency performance and a variable terminator (VT2) 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 7.
4. Install any desired filters, optics, adapters, or fiber adapters to the input
aperture.
The DET20C2 was designed to allow maximum accessibility to the
photodetector by having the active area 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
5. During alignment, take appropriate precautions, such as using reduced
radiation power, or other precautions, and use proper eye and/or skin
protection as recommended by the radiation source manufacturer.
6. Apply a light source to the detector.
Rev B, May 7, 2019
Caution!
the diode and/or the fiber.
Chapter 3: Setup
Page 3