Wideband Mixed Signal Separation Based on Photonic Signal Processing

Abstract

The growing needs for high-speed and secure communications create an increasing challenge to the contemporary framework of signal processing. The coexistence of multiple high-speed wireless communication systems generates wideband interference. To protect the security and especially the privacy of users’ communications requires stealth communication that hides and recovers private information against eavesdropping attacks. The major problem in interference management and stealth information recovery is to separate the signal of interest from wideband interference/noise. However, the increasing signal bandwidth presents a real challenge to existing capabilities in separating the mixed signal and results in unacceptable latency. The photonic circuit processes a signal in an analog way with a unanimous frequency response over GHz bandwidth. The digital processor measures the statistical patterns of the signals with sampling rate orders of magnitude smaller than the Nyquist frequency. Under-sampling the signals significantly reduces the workload of the digital processor while providing accurate control of the photonic circuit to perform the real-time signal separations. The wideband mixed signal separation, based on photonic signal processing is scalable to multiple stages with the performance of each stage accrued.

Photonic analog signal processing and neuromorphic computing [Invited]

“…Because spectral methods are not used for the separation process, signals can safely exist in the same bandwidth as each other. This enables a type of space-division multiplexing that does not require separate transmission mediums for each signal [45] and shows potential for increasing the capacity of fiber optic communication networks [38,39,42] . In addition, because the algorithm makes no attempt to digitally reproduce the signals being analyzed, the sampling circuitry is capable of working well below the Nyquist sampling limit [2,3] .…”

“…Schematic of a common single-output photonic BSS circuit. TD, tunable delay; AM, amplitude modulator; TA, tunable attenuator; PD, photodiode; ADC, analog-to-digital converter [42] .…”