1310 nm Narrow Linewidth Laser Assisted by the Feedback of Double-FBGs

Narrow linewidth lasers with kHz or Hz have attracted tremendous attention due to their versatile applications in optical fiber sensing and optical fiber communication fields. This is because the efficiency of these fields depends on the quality of the laser source employed. This paper proposes, simulates, and experimentally demonstrates a dual cavity fiber Bragg grating assisted feedback structure. Based on the Rayleigh backscattering mechanism, Vernier effect, and interference phenomenon, the 2 MHz linewidth of a 1310 nm distributed feedback laser was highly compressed to ~580 Hz with a side mode suppression ratio as high as 34 dB. The output power of our proposed laser was found to be stable at 2.0 mW. The outcome of this work presents an idea centered on laser linewidth compression that applies to DFB lasers operating at various wavelengths.