High spectral purity GaSb-based blazed grating external cavity laser with tunable single-mode operation around 1940nm

• DOI: 10.1364/oe.439255
• Publication Date: 2021-09-27T12:03:30Z
• Authors: Tianfang Wang; Chengao Yang; Yi Zhang; Yihang Chen; Jinming Shang; Yu Zhang; Yingqiang Xu; Zhichuan Niu
• Keywords: Waveguide; Anti-reflective coating

In this article, we present a tunable GaSb-based blazed grating external cavity laser (BG-ECL) with high spectral purity and output power single-mode operation around 1940nm. The drastic increase in selectivity optical results from the employment of single-transverse-mode operating narrow ridge waveguide diode an optimized AR coating on front facet. stable fundamental spatial mode beam enables efficient collimation coupling efficiency grating, leading to stronger wavelength-selective feedback. proper low reflectivity straight effectively suppresses internal lasing without causing extra loss. As result, BG-ECL device exhibits excellent comprehensive performance side suppression ratio (SMSR) over 50 dB exceeding 30 mW within 70 nm tuning range. A maximum SMSR 56.26 35.12 was observed continuous-wave operation. By increasing working temperature laser, range can be further extended 100 noticeable degradation performance.