On-chip quantum homodyne detectionsystem
We will implement a single-photon counting quantum homodyne detection system with superior timing and low-noise performance on a silicon chip. A key feature of the SURQUID QHD system will be inherent stability for interferometric sensing applications and a high level of system integration. Using nanophotonic circuit design, we will achieve scalability of our detection platform that will be fabricated in a semiconductor industry fab. Operating in the telecom C-band, our QHD system that will provide enhanced sensitivity with SNSPD multi-detector architectures. The nanophotonic chip will integrate arrayed waveguide gratings, balanced directional couplers and waveguide coupled SNSPDs to realize the QHD scheme. To exploit quantum sensitivity in lidar, we will operate the QHD system on two wavelengths in parallel with ultrafast waveguide-integrated SNSPDs featuring <3 ps timing accuracy (jitter), which allows for a “coarse” determination of the position of an object to within 1mm via time-of-flight (TOF) measurements. Within the TOF measured spatial uncertainty, precision distance detection will be carried out using quantum homodyne detection. For 3D surface profiling we will implement a scanning beam detection system where each pixel under test is separately assessed with the QHDS. The photons returning from the target will be couple into nanophotonic waveguides via efficient 3D optical interfaces where they are mixed with a local oscillator field and recording with high-speed, low-noise SNSPDs. The electrical detector response will be processed with novel time to digital (TDC) application specific integrated circuits (ASIC) that allow to take advantage of the high timing accuracy and fast 2D scan rates realized with our SNSPDs.