A Stable Dual-Wavelength DFB Semiconductor Laser With Equivalent Chirped Sampled Grating

A monolithic integrated dual-wavelength DFB semiconductor laser is fabricated and experimentally demonstrated. Utilizing the reconstruction-equivalent chirp (REC) technique, dual-wavelength lasing is obtained by introducing two symmetric equivalent phase shifts in a chirped sampled Bragg grating. The laser operates at 1650 nm and the wavelength spacing is about 0.8 nm at room temperature. The frequency of the beat signal between the two wavelengths is 88.47 GHz, and the linewidth of the beat signal is 5.1 MHz. Based on the REC technique, the grating pattern can be fabricated by using holographic exposure combining with conventional lithography. This work provides a simple and cost-effective way to achieve dual-wavelength semiconductor laser.