Narrow Linewidth Single-Mode Slotted Fabry–Pérot Laser Using Deep Etched Trenches

We report the design and experimental results of a narrow linewidth single-mode slotted Fabry-Pérot laser by using deep etched trenches. Good performances in lasing threshold, side-mode suppression ratio, and linewidth are obtained. The deep trench is effective in reducing the cavity loss compared to the previously investigated shallow etched slots, resulting in a lower threshold and a narrower linewidth (down to ~80 kHz). Since no grating and multiple epitaxial growth are required, such a simple, compact, and monolithic semiconductor laser with narrow linewidth may have potential applications in coherent communication systems.