Characterization and Optimization of an Eight-Channel Time-Multiplexed Pulse-Shaping System

High-performance optical pulse shaping is paramount to photonics and laser applications for which high-precision optical waveforms must be generated. We investigate the design and performance of a time-multiplexed pulse-shaping (TMPS) system in which optical waveforms from a single pulse-shaping unit are demultiplexed and retimed before being sent to different optical systems. This architecture has the advantages of low cost and low relative jitter between optical waveforms because a single pulse-shaping system, e.g., a high-performance arbitrary waveform generator driving a Mach-Zehnder modulator, generates all the waveforms. We demonstrate an eight-channel TMPS system based on a 1 × 8 LiNbO
₃
demultiplexer composed of four stages of 1 × 2 Δβ phase-reversal switches. It is shown that optimal demultiplexing, i.e., low insertion loss and high extinction ratio between channels, requires optimization in dynamic operation because of the slow component of the switches' response. We demonstrate losses lower than 5 dB, extinction ratios of the order of 70 dB for a four-channel system and 50 dB for an eight-channel system, and jitter added by the demultiplexer smaller than 0.1 ps.