Author(s): Wang, TF (Wang, Tianfang); Yang, CG (Yang, Chengao); Zhang, Y (Zhang, Yi); Chen, YH (Chen, Yihang); Shang, JM (Shang, Jinming); Zhang, Y (Zhang, Yu); Xu, YQ (Xu, Yingqiang); Niu, ZC (Niu, Zhichuan)

Source: OPTICS EXPRESS Volume: 29 Issue: 21 Pages: 33864-33873 DOI: 10.1364/OE.439255 Published: OCT 11 2021

Abstract: In this article, we present a tunable GaSb-based blazed grating external cavity laser (BG-ECL) with high spectral purity and high output power single-mode operation around 1940nm. The drastic increase in spectral selectivity and optical power results from the employment of a single-transverse-mode operating narrow ridge waveguide laser diode with an optimized AR coating on the front facet. The stable fundamental spatial mode output beam from the laser diode enables efficient collimation and high coupling efficiency with the blazed grating, leading to stronger wavelength-selective feedback. The AR coating with proper low reflectivity on the straight waveguide effectively suppresses the internal cavity mode lasing without causing extra optical loss. As a result, the BG-ECL device exhibits excellent comprehensive performance with a side mode suppression ratio (SMSR) over 50dB with optical power exceeding 30 mW within a 70 nm tuning range. A maximum SMSR of 56.26 dB with 35.12 mW output power was observed in continuous-wave operation. By increasing the working temperature of the diode laser, the tuning range can be further extended to over 100 nm without noticeable degradation in spectral and output power performance. (C) 2021 Optical Society of America under the terms of the OSA Open Access Publishing Agreement

Accession Number: WOS:000708940500092

ISSN: 1094-4087

Full Text: https://www.osapublishing.org/oe/fulltext.cfm?uri=oe-29-21-33864&id=460103