Leong Chuan Kwek

An integrated chip platform for CV-QKD system based on time and polarization multiplexing is designed and demonstrated. A proof-of-principle test is conducted, which shows the measurement results for key components. The secure key rate by simulation can reach 4 kbit/s at 40 km distance per transmission band.

An integrated chip system for MDI-QKD is demonstrated. The MDI-QKD transmitter chips and server chip work on a key rate per pulse of 2.923 × 10^(-6) over a distance corresponding to 50-km optical fiber with 25% detection efficiency.

We design and fabricate a quantum photonic circuit to generate a 4-qubit state to load single qubit information and implement a quantum error correction code to demonstrate its capability of detecting and correcting a single-bit error. The encoded quantum information can be reconstructed from different types of errors and achieve an average state fidelity of 86%. We further extend the scheme to demonstrate fault-tolerant measurement-based quantum computing that allows us to redo the qubit operation against the failure of the teleportation process.

We map the perfect matching problem in graph theory to a reconfigurable GBS model with the connection of the Hafnian of a matrix. We configure the linear optical circuit and squeeze parameter of the GBS model according to the decomposed unitary matrix and diagonal matrix of the graph’s adjacency matrix. The perfect matching numbers can be directly acquired from the 4-photon coincidence counts with a distribution similarity of 0.9304.