Spatial Phasers for Real-Time Spectrum Analysis
Real-time spectrum analysis is a ubiquitous signal processing operation in science and engineering. It involves real-time frequency discriminating devices that separate the various spectral components of a signal in either the space domain or the time domain. Typical applications include spectral analysis for instrumentation, electromagnetics and biomedical imaging [Metz et al. (2014); Lee and Wight (1986a); Gupta et al. (2009)], ultrafast optical signal processing [Goda and Jalali (2013); Goda et al. (2009)], and dense wavelength demultiplexing communication systems [Xiao and Weiner (2004); Supradeepa et al. (2008)], to name a few. The heart of such systems is a spatial dispersive device. Typical devices are optical prisms, diffraction gratings, arrayed-waveguide gratings (AWGs) [Saleh and Teich (2007); Goodman (2004)], Bragg gratings [Kashyap (2009)], phasers [Caloz et al. (2013)], LWAs [Caloz et al.
(2011)], and virtual image phased arrays (VIPAs) [Shirasaki (1996)]. Among these several spatially dispersive devices, diffraction gratings and LWAs emerge as two most practical components to be employed for spectrum analysis applications and will be described next.