Extended InGaAs Biased Detector
Chapter 6: Trouble Shooting
Rev A, December 27, 2017
Page 11
Chapter 6 Trouble Shooting
Problem
Suggested Solutions
There is no signal response.
Verify that the power is switched on and all
connections are secure.
Verify the proper terminating resistor is
installed if using a Voltage measurement
device.
Verify that the optical signal wavelength is
within the specified wavelength range.
Verify that the optical signal is illuminating
the detector active area.
Connect the DET to an oscilloscope without
a terminating resistor installed. Most general
purpose oscilloscopes will have a 1 M
Ω
input
impedance. For visible detectors, 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
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 state. However,
because the detector is unbiased, operation
in this mode is not recommended.
The output appears AC
coupled with long rise times
and the power switch ON.
This is usually an indication that the battery
level is low and needs to be changed. See
the Battery Check and Replacement Section.
