Chapter 3 Setup - THORLABS PDA36A2 User Manual

Si Switchable Gain 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.
1. Unpack the optical head, install a Thorlabs TR-series Ø1/2" or Ø25 mm
post into one of the mounting holes, located on the bottom and side of
the sensor, and mount using a PH-series 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.
2. Connect the power supply 3-pin plug into the power receptacle on the
PDA36A2.
3. Plug the power supply into a 50 to 60Hz, 100 V / 120 V / 230 V power
outlet.
4. Attach a 50 Ω coax cable (i.e. RG-58U) to the output of the PDA. When
running cable lengths longer than 12" we recommend terminating the
opposite end of the coax with a 50 Ω resistor (Thorlabs p/n T4119) for
maximum performance. Connect the remaining end to a measurement
device such as an oscilloscope or high speed DAQ card. Caution: Many
high speed oscilloscopes have input impedances of 50 Ω. In this case,
do not install a 50 Ω terminator. The combined loads will equal 25 Ω
which could allow ~135 mA of output current. This will damage the
output driver of the PDA36A2.
5. Power the PDA36A2 on using the power switch located on the top side
of the unit.
!
The PDA36A2 was designed to allow maximum accessibility to the
photodetector by having the active area surface of the diode flush with the
outside of the PDA housing. When using fiber adapters, make sure that the
fiber ferrule does not crash into the detector. Failure to do so may cause
6. Install any desired filters, optics, adapters, or fiber adapters to the input
aperture.
7. 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.
8. Apply a light source to the detector. Adjust the gain to the desired
setting.
Rev A, December 27, 2017
Caution!
damage to the diode and or the fiber.
Chapter 3: Setup
!
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