Photonics Assisted Analog-to-Digital Conversion of Wide-Bandwidth Signals by Orthogonal Sampling

Photonics-assisted analog-to-digital converters could be a solution to the bandwidth limitations faced by electronic analog-to-digital converters (EADCs) in today’s wireless networks and electrical measurement devices. Orthogonal sampling with sinc-pulse sequences is a technique that can be used to down convert high-bandwidth input signals into low-bandwidth sub-signals, which can then be detected and processed by low-bandwidth electronic devices. This method is superior to electronic sample and hold circuits, as it adds no aperture jitter, and it is based on a multiplication rather than switching. As we will show by experiments, the proposed method shows a signal-to-noise and distortion and effective number of bit improvement of 9.2 dB and 1.5 bit, respectively, for detecting a 14.5 GHz signal. The scheme is simple and can be integrated along with the low bandwidth EADCs into a single chip for high-bandwidth, improved performance, microwave and wireless signal measurement devices.