© 2019 Thorlabs
3 Operating Instruction
7
P
opt,1
and P
opt,2
- optical input power
G - transimpedance gain of the RF output
The responsivity
Â
(
l
)
for a given wavelength can be read from the individual curves in section
Technical Data to estimate the
RF OUTPUT
voltage. Please note that the given responsivity
curves represent typical values - individual responsivity may deviate.
The maximum
RF OUTPUT power
is typ 18 dBm at 1 dB compression. To explain that:
An ideal amplifier would be a linear device - it's gain is constant at any input power level. In
reality, the output power of the amplifier is limited (e.g. by supply voltage). That means, with in-
creased input power the amplifier becomes saturated. Before the saturation is reached, a re-
duction in gain takes place - the result is a compression effect. The 1 dB compression point is
defined as the output power where the gain is 1 dB less than the small signal gain.
In order to avoid saturation, the output signal level should not exceed this 1-dB-compression
point.
MONITOR Outputs
The signal monitor outputs (
and
MONITOR-
) allow observation of the input power
level and can be used as individual power indicators. These outputs can also be used to meas-
ure RF (up to 3 MHz) modulated signals on each detector separately. The maximum output
voltage swing of the
MONITOR
output is +10 V for high impedance loads (+1.5 V into 50
W
).
Saturation of
MONITOR
outputs will occur at optical input power level greater than 1 mW, de-
pending on the detector's wavelength response.
The amplifier offset voltage is factory set to zero at 23°C ambient temperature. A small drift dur-
ing a short warm-up period (~5min) may occur. For exact DC light level measurements a con-
stant temperature environment is recommended.
3.4 Mounting
The PDB48xC-AC is housed in a rugged shielded aluminum enclosure.
For post mounting an adapter can be attached to the bottom or side surface using four M2x8
screws (see below). This adapter supports #8-32 as well as M4 post mounts. The M4 tread is
marked.
Summary of Contents for PDB48*C-AC series
Page 1: ...Balanced Amplified Photodetectors PDB48xC AC Operation Manual 2019...
Page 2: ...Version Date Item No 1 6 14 Jan 2019 M 0009 510 666 Copyright 2019 Thorlabs...
Page 19: ...2019 Thorlabs 5 Appendix 17 5 2 Dimensions PDB48xC AC Mechanical Drawing...
Page 20: ...2019 Thorlabs 18 PDB48xC AC 5 3 Certifications and Compliances...
Page 23: ...www thorlabs com...
