A Compact Self-Injection-Locked Narrow-Linewidth Diode Laser with Narrowband Dielectric Filter

The self-injection-locked diode laser can significantly reduce the linewidth down to a sub-100 kHz level but requires optical filtering that is much narrower than cavity linewidth. Such usually sophisticated and beyond capability of normal dielectric coating approach. Here we develop 0.16 nm narrowband using Fabry–Perot filter (HFFPF) for narrow demonstration cost-effective diode. Single-longitude-mode output achieved, with beat ~66 high side mode suppression ratio over 60 dB. This setup mass production thus suitable various applications such as ranging, LIDAR, communication, holographic.