A Novel Highly Stable Dual-Wavelength Short Optical Pulse Source Based on a Dual-Loop Optoelectronic Oscillator With Two Wavelengths

Abstract

A novel scheme of a highly stable dual-wavelength short optical pulse source (SOPS) based on a dual-loop optoelectronic oscillator (OEO) with two wavelengths is demonstrated. The structure of the dual-loop OEO with two wavelengths can suppress the random beating noise effectively and generate the microwave signal with low phase noise ( $-$ 122.4 dBc/Hz at 10 kHz) . It consists of two directly modulated lasers and a phase modulator (PM) . The light that is directly modulated by the large signal generated from the OEO is injected into the PM to achieve remarkable chirp. Then, by optimizing the length of the dispersion compensating fiber, the optical pulses are further compressed. In the experiment, the SOPS with dual wavelengths is generated simultaneously. The repetition rate, pulse width, and timing jitter of the SOPS are 10 GHz, 2.9 ps, and 12.5 fs, respectively. In particular, the loop drift of the OEO is effectively compensated by fiber stretchers using phase-locked-loop technology. The frequency drift of the microwave signal is less than $\pm$ 73.3 mHz for a long-term measurement with a duration of 1 h. Therefore, the long-term stability of SOPS is guaranteed.