Spectral Efficiency Improvement in Photonic Time-Stretch Analog-to-Digital Converter via Polarization Multiplexing

Dual-polarization photonic time-stretch technique, which exploits polarization multiplexing to improve the spectral efficiency of the conventional photonic time-stretch technique, is proposed. This technique reduces the demand on optical bandwidth for large record length of the photonic time-stretch analog-to-digital converter. It is shown that this technique can capture high-bandwidth radio-frequency signals (>;10-GHz instantaneous bandwidth). Experimentally, 12.5-Gb/s data eye-diagram measurement using this preprocessor operating in equivalent-time mode is demonstrated.