Reconfigurable Linear Optical FM Discriminator

We present a reconfigurable optical discriminator filter for frequency modulated microwave-photonics link applications. The filter is based on a simplified ring-assisted Mach-Zehnder interferometer configuration. It enables conversion of a highly linear frequency to amplitude modulation. Operations in a fixed bandwidth (BW) of 30 GHz and a tunable bandwidth from 10 to 30 GHz are achieved using third- and fifth-order filters. A balanced frequency discrimination architecture with electronically reconfigurable transfer characteristics is demonstrated. We measured a output-third order intercept point (OIP3) linearity improvement over that of a dual-output Mach-Zehnder.