Frequency Swept Fiber Ring Laser Based on Optical Parametric Process With Single-Longitudinal-Mode Operation

A stable and wavelength-tunable single-longitudinal-mode (SLM) oscillation with sweeping rate of 1.17 kHz based on a fiber-optical parametric oscillator (FOPO) is proposed and demonstrated. In order to perform sweeping SLM operations, three types of filters, a fiber Fabry-Pérot tunable filter (FFP-TF), a subring cavity, and an autotracking filter which is formed by an unpumped erbium-doped fiber (EDF), are incorporated inside the cavity. The output of the laser can be swept continuously from 1530 to 1543 nm and 1569 to 1584 nm with the average output power exceeding 3 dBm. The short-term linewidth of the laser output measured by self-homodyne method is about 66.6 kHz with a side-mode suppression ratio of 60 dB at 1538 nm.