a 5$\mu$m x 1mm semiconductor waveguide that is pumped by an external CW Ti-Sapphire laser at 783 nm. The broadband, CW probe (with horizontal polarization) and reference (with vertical polarization) light are separated by a polarization beam-splitter. The reference light is immediately sent to and detected by the reference detector in the detection section. The probe light is sent to the transceiver section and emitted through an optical collimator towards the target object. The back-scattered probe light from the target object is collected by a telescope and detected by the probe detector in the detection section. To simulate strong environmental noise, broadband CW noise light from a light-emitting diode shines towards the collection optics, leading to a large number of noise photons getting detected on the probe detector. The three sections of the setup are connected via single-mode fibers, which enables a flexible system deployment.

Semiconductor Sources Of Non-classical Photon Pairs
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The semiconductor SPDC waveguide used is based on the AlGaAs material platform. The dimension of the waveguide is $\simeq 1$mm long and $\simeq 5\mu m$ wide as shown in Fig. \[SAMPLE\]. The ridge and the substrate of the waveguide are based on Bragg structure, which consists of alternating 