Research On Single-photon Source And Switch Network Of Silicon-based Microring Resonator

A single photon source is one of the most essential components in quantum computing and quantum communication networks.K.L.M proposed to use measurement to introduce nonlinear processes,paving the way for linear quantum computing.Linear quantum computing requires high-quality single-photon sources which should have the characteristics of single-photon,determinism,high indistinguishability and high brightness.The silicon-based integrated singlephoton source which is compatible with the Complementary Metal Oxide Semiconductor(CMOS)process,can be integrated on a small chip.It has the advantages of phase stability and easy control.The subsequent photonic circuits can also be fully integrated with it.So it has broad prospects for development.The silicon-based integrated single-photon source uses the spontaneous four-wave mixing to generate photon pairs.This process is probabilistic,various methods such as time division multiplexing and frequency division multiplexing can be used to achieve determined single-photon source.The key components of multiplexed single-photon sources are singlephoton source arrays and switch networks.The thesis focuses on single-photon source and switch network architecture.It mainly conducts in-depth research on key issues such as the design of micro-ring single-photon source,wavelength monitor and locking,and switching network architecture.The main contributions and innovations are in the following four aspects:1.Microring-based single-photon source array and wavelength locking: In view of the problem of insufficient locking accuracy due to photodetector when the microring resonator is locked,it is proposed to directly utilize single photon counting.The result of counting of the single-photon detector is fed back to control the resonant wavelength of the microring more precisely.The performance of the single-photon source based on the microring is theoretically and experimentally analyzed,and a parallel wavelength locking of two microrings based on single photon counting is completed.Single-photon sources based on spiral waveguides and microring resonator is theoretically modeled and analyzed,and its performance characteristics such as CAR,purity,and heralding probability are experimentally characterized.2.Non-blocking switch network based on series dual-rings: In view of the requirement of multiplexed single photon source for low loss and flexible expansion of switching network,a switch network based on Half-Crossbar is proposed,which is more flexible in expansion,in which any switching function can be realized by using fewer basic switch units.In this study,a 4×4switch network is designed,and its insertion loss,crosstalk,switching time,and high-speed signal transmission capability are all characterized experimentally.The network is applied to the multiplexed single-photon source architecture,and the insertion loss is positively correlated with the N-1 power loss of the basic unit,where N is the number of single-photon sources.The heralding efficiency can be increased to 1 by increasing the number of single-photon sources,but the probability of generating single-photon sources is limited by the compressive strength.In the case of low compressive strength,the probability of generating single-photon sources can be increased to 99% by increasing the number of single-photon sources.3.Strictly non-blocking switch network based on dual-rings: In order to reduce the number of switch stages and ensure the flexibility of the switch network,a connection from any input port to any output port can be established at any time when routing photons without affecting the established connection state.Based on the requirement,the study designs a 4-port network based on a Double-layer structure with logarithmic switch stage increase speed,which can achieve strictly non-blocking switch without first-order crosstalk.This work also analyzes the relationship between the probability of single-photon generation and the number of single-photon sources under the Double-layer structure.The network increases the number of switching stage with O(log2(N)),so the loss will be lower compared with network mentioned above.When the switch network loss is high,high single-photon generation probability cannot be achieved even by increasing the number of single-photon sources,but in the case of a low-loss switch network,increasing the number of single-photon sources can achieve high single-photon generation probability,so it is more advantageous to apply the network to the multiplexed single-photon source architecture.4.Wavelength monitor based on double rings: Aiming at the wavelength monitor of microrings,it is proposed to use twin-Fano interference phenomenon to realize the ultra-highresolution wavelength monitoring.The interference of two beams of light with different phases in the microring resonator will produce Fano effect,which appears as a steep interference spectral line,and the wavelength monitor can be realized by using the steep spectral line.A Mach-Zehnder Interference(MZI)structure is used with one of the MZI’s Multi-mode Interference(MMI)replaced with a series double ring.By adjusting phase difference of two arms of the MZI,the phase of the two beams entering the microring is changed.And it can also change the slope of the spectral line with double "X" spectral lines of self-alignment function.The test result shows that the wavelength monitor can achieve a wavelength resolution of 1pm.