THORLABS INT-POL-1300, Operation Manual

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3 Detailed Description
INT-POL-1300 / page 7
3.2 Optical Input and Detector Response
The INT-POL-1300 Balanced Polarization Diversity Detector subassembly is
equipped with two FC/APC adaptors to be connected to your application. Corning
SMF-28
TM single mode fiber is used for internal fiber network. Input polarization has
to be adjusted in order to achieve a desired polarization splitting ratio. Depending on
input polarization typical insertion loss for each optical path is about 0.5 dB.
NOTE
FC/APC connectors must be used for all INPUT and OUTPUT connectors.
Carefully clean the connectors prior to connection.
The internal fiber network is carefully length-matched for both SOP to achieve maxi-
mum possible common mode rejection ratio CMRR (maximum noise suppression).
INT-POL-1300 uses pigtailed InGaAs PIN photodiodes. Figure 3 shows a typical
responsivity curve for this photodiode type.
Figure 3: INT-POL-1300 detector responsivity
This wavelength dependency affects the output signal amplitude. In order to com-
pensate this responsivity, the measured electrical signal must be multiplied by the
normalized wavelength dependent responsivity.