Re-Configurable, Photonic-Wire-Bonded Integrated Circuit for Degenerate and Non-Degenerate Photon Pair Generation

A fundamental challenge associated with parametric sources is the fact that the conversion efficiency from the pump field to the quantum field is typically quite low, such that the residual pump light must be effectively filtered from the channels that carry the quantum photonic states. Here, we present an integrated silicon photonic circuit that can perform parametric generation, pump rejection, and wavelength de-multiplexing (WDM) of quantum correlated (both degenerate and non-degenerate) photon pairs at telecommunication wavelengths. The circuit utilizes an all-pass micro-ring resonator (MRR) as the photon pair source, and three separate 4-port contra-directional couplers (CDCs) as filters. One of the three filters acts as a pump reject filter, and the other two as WDM filters. The WDM filters have two different center wavelengths and two heaters attached to them for tuning. The chip is connected on opposite sides to two fiber arrays using photonic wire bonds to facilitate alignment-free operation using four distinct filter configurations for generating both degenerate and non-degenerate photon pairs. The best coincidence-to-accidental ratio (CAR) for the non-degenerate pairs is 1070 at an estimated pair generation rate (PGR) of 2.1 kHz at the output of the MRR. The maximum CAR for the degenerate photon pairs is 348 at an estimated on-chip PGR of 6.8 kHz.