Decoupling and one-time elimination of timing skew in time-demultiplexing photonic analog-to-digital converter for high-resolution wideband signal acquisition

作者：Ruiheng Qin, Na Qian, Defu Zhou, Bowen Ma, and Weiwen Zou*
摘要：Temporal alignment between demultiplexing signal and sampled signal for complex wideband signals greatly increases the difficulty of designing high-speed and high-resolution photonic analog-to-digital converters (PADCs). We present a vector description to decouple timing skew from the phase frequency response in time-demultiplexing PADC. We demonstrate that the calibration can be optically implemented with true time delay effects and the broadband input can be one-time calibrated through several single-frequency signals. For verification, we configure out a 40 GSa/s PADC with 8 interleaved sub-channels. The timing skew-induced spurs across the whole Nyquist band are effectively suppressed, making the PADC acquire wideband signal with 16 GHz instantaneous bandwidth. The spurious free dynamic range (SFDR) is enhanced to ~55 dB, and the effective number of bits (ENOB) is improved from ~5.5 bits to ~8 bits within 20 GHz. It is nearly 1 bit better than the recently reported time-demultiplexing PADC under the comparable input frequencies.
出版源：Optics Letters
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