Wideband Rapidly Tunable Delay-Controlled Optoelectronic Oscillator

Abstract

With the recent advancements in photonic integrated circuits, integrated RF photonics has increasingly been considered as a viable avenue to meet the demands of many emerging applications in telecommunication, sensing and signal processing. In this paper, an integrated, rapidly tunable, wideband optical delay line is used to implement an optoelectronic oscillator that can be continuously tuned from 594 MHz to 634 MHz. The oscillator exhibits a relatively flat modulation response at high frequencies (larger than 400 MHz), accommodating wideband fast frequency chirp generation with applications in radar and imaging. The on-chip variable delay line is characterized by continuously delaying an ultra-wide band 0.5-5 GHz monocycle pulse between 0-100 ps. The photonic integrated chip consists of silicon nanowaveguides, phase modulators, multimode interference coupler, a Mach-Zehnder interferometer, and a photodiode. The chip is fabricated on IME 180 nm Silicon Photonics platform and has an area of 0.55 mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> .