Ultra Storage-Efficient Time Digitizer for Pseudorandom Single Photon Counter Implemented on a Field-Programmable Gate Array

Pseudorandom single photon counting is a novel time-resolved optical measurement method, which is advantageous over convention techniques in terms of data-acquisition speed and system cost. As a critical component of the pseudorandom single photon counter, the photon arriving time digitizer should be storage efficient for a high photon counting rate, while maintaining good time accuracy. We report an ultra storage-efficient time digitizer for a pseudorandom single photon counter in this paper, which is based on the asynchronous serial communication and can store the arriving time of every photon in 1-b memory space. In addition, a novel comb-wave modulator is proposed to achieve the dc balance required for asynchronous serial communication. Our prototype implemented on field-programmable gate arrays provides a time resolution of 400 ps. It can register up to 4.2-Giga photon arriving time tags with 1024 × 32-b memory space.