Chip-Level GHz Capable Balanced Quantum Homodyne Receivers

We present a design of balanced homodyne receivers suitable for ultra-low noise quantum applications such as continuous-variable key distribution and random number generation. For best bandwidth performance die-level low-parasitic photodiode together with low-noise high-speed transimpedance amplifier are explored planar lightwave circuit splitter chip serving photomixer. Bandwidths 750 MHz 2.6 GHz were accomplished while maintaining optimum performance, evidenced by very high quantum-to-classical ratios 26.8 18.6 dB, respectively. A common-mode rejection ratio at least 40 dB was achieved frequency range up to 1 GHz. Its application evaluated means estimations under strict untrusted receiver assumption, showing its potential generating 43 Mbit/s secure-key rate over reach 10 km, whereas 100 could be supported shorter reaches. Moreover, the clearance values can enable quality generation Gb/s rates. The multi-purpose operation designed classical communications examined reception sensitivities −55.8 −52.6 dBm 500 Gbit/s quadrature phase shift keying transmission, respectively, using receiver. faster enabled duobinary transmission −14.8 sensitivity.