Electrical Output - THORLABS APD110 Series Operation Manual

The maximum OUTPUT voltage swing is 3.6 V at High-Z termination. Saturation of the
OUTPUT will occur at optical input power greater than CW Saturation Power listed in
tions . If necessary, use external neutral density filters or attenuators to reduce the input light
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level. Please note that the Avalanche Photodetectors are extremely sensitive to unwanted stray
light. Carefully shielding of the Avalanche Photodetectors from any unwanted light sources is
essential. Common techniques to minimize the influence of stray light include baffling or other
opaque barriers like black cloths, beam tubes or using appropriate band pass filters in front of
the detector.
Attention
The optical damage threshold is 1 mW. Exceeding this value will permanently destroy the
Avalanche Photodetector!

3.1.2 Electrical Output

Thorlabs APD110x/120x Avalanche Photodetectors deliver an OUTPUT voltage, which is a
function of incident light power
factor (see Typical Detector Responsivity Curves
(l) for a given wavelength can be read from the spectral responsivity curves (see
Â
·
M
nical Data ) to estimate the OUTPUT voltage.
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· The M factor is factory set to 50 (APD120A, APD120A2) or 10 (APD110C) at 23°C ambient
temperature. The amplifier's transimpedance gain
voltage is reduced by a factor of 0.5 if connected to a 50 W load.
The maximum output voltage swing of OUTPUT is 3.6 V for high impedance loads (1.8 V into
50 W). Depending on the wavelength responsivity
amplifier will reach saturation at optical input power greater than CW Saturation Power listed in
specifications. To avoid saturation, keep the output signal below the specified maximum output
voltage.
The output of the APD110x/120x Avalanche Photodetectors is a BNC connector.
The amplifier offset voltage is factory set to zero at 23°C ambient temperature. Due to the very
high transimpedance gain, small temperature changes may affect offset voltage. Therefore it is
recommended to use the Avalanche Photodetectors in a constant temperature environment
after a short warm up period (~5 min) for exact DC light level measurements.
In the appendix, typical curves for
tion and M Factor Temperature Dependency
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© 2019 Thorlabs
, detector's responsivity
P
opt
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Output Frequency Response
19
(l) at a given wavelength and M
Â
M
), and transimpedance gain
is 100 kV/A. Please note that OUTPUT
G
of the detector and the M factor, the
Â(l)
,
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can be found.
3 Operating Instruction
specifica-
:
G
Tech-
Spectral Noise Distribu-
7