Balanced APD homodyne receiver for quantum applications

Abstract

Performance of linear avalanche photodiodebased balanced homodyne receiver (APD BHD) is examined and compared to reference BHD based on PIN photodiodes, in terms of common mode rejection ratio (CMRR), quantum-to-classical noise clearance (QCNR) and sensitivity in coherent reception of quadrature phase shift keying (QPSK) modulation format. NIST randomness validation was performed on sampled data for quantum random number generator (QRNG). Achieved CMRR values were 50 dB and 30 dB at 100 MHz and 1 GHz, respectively. QCNR of 20 dB at low input power of -20 dBm was demonstrated. Optical sensitivity of APD BHD coherent receiver compared to its PIN BHD counterpart can be improved by 3 dB at low local oscillator (LO) powers, whereas for high LO powers the sensitivity of APD BHD approaches the values for PIN BHD.

Research on large-bandwidth balanced homodyne detector for quantum detection

“…It plays an important role in the field of quantum detection and is an important bridge to complete the detection of optical signals to electrical signals. The main parameters of BHD are: Bandwidth, gain, electrical noise, signal-to-noise ratio, common-mode rejection ratio, etc [2] . Gain affects BHD's ability to amplify signals, electrical noise affects the additional noise introduced by BHD, and BHD's signal-to-noise ratio will directly affect the effective content of the signal [3] [4] , the common mode rejection ratio represents the ability of BHD to effectively eliminate noise fluctuations and suppress classic common mode signals, while amplifying orthogonal noise fluctuations.…”