PROJECT TITLE :

A Widely Tunable Optoelectronic Oscillator Based on Directly Modulated Dual-Mode Laser

ABSTRACT:

A widely tunable optoelectronic oscillator (OEO) based mostly on a directly modulated monolithic integrated twin-mode amplified feedback laser (AFL) is proposed and experimentally demonstrated. During this OEO theme, the functions of the laser source, the intensity modulator, and the tunable high- $Q$ RF filter are all realized through an AFL chip. On one hand, the beating frequency of the two modes defines the central oscillating frequency, which functions as an energetic tunable microwave photonic filter. On the other hand, by benefiting from the photon–photon resonance, the laser has high modulation efficiency around the beating frequency that is way beyond the intrinsic modulation bandwidth of the lasers. It eliminates the employment of high-speed external modulators and dramatically reduces the brink gain of the oscillator. By tuning the injection currents of the laser sections, stable microwave signals that are continuously tunable from twenty eight to 41 GHz with signal-sideband section noise below −106 dBc/Hz (at a ten-kHz offset) and threshold electronic gain only 27 dB are experimentally realized.