Implementation and investigation of mode locking in GaN‐based laser diodes in external cavity configuration

Abstract

Investigation of spectro-temporal characteristics of short-pulse generation from a violet-blue AlGaInN multi-section laser diode implemented in an external cavity is demonstrated. The front facet is coated with a single layer of anti-reflection coating, resulting in superluminescent diodes with a broad spectrum. The coated diode is placed in an external cavity in Littrow configuration for wavelength-tuning, and in Littman-Metcalf configuration for ultrashort pulse generation. We report on fundamental, harmonic, as well as hybrid mode locking. Compensating for the group velocity dispersion, we compress the pulse duration down to 2 ps, which is at the resolution limit of the streak camera. Mode locking and sub-ps pulse generation are hindered by the photon density-induced gain saturation, manifested as mode competition and mode clustering superimposed with mode locking. We show, that hybrid mode locking can suppress the mode competition successfully

Group-III-nitride and halide-perovskite semiconductor gain media for amplified spontaneous emission and lasing applications

“…In a different role, the integrated absorber section can be used to suppress lasing. This leads to the production of a superluminescent diode that operates in the ASE regime [204,234,[248][249][250][251]. In section 2.3, the InGaN-based superluminescent diode is discussed separately, and a review article is recommended for further reading.…”

Single-Port Superluminescent-Diode Gain-Chip for Tunable Single-Wavelength and Dual-Wavelength Blue-Laser

“…Previously, the implementation of tunable lasers based on SLDs in EC configurations focused on the near-infrared and red wavelength regime [17]- [21]. The closest investigations using InGaN-based devices are SLD or its closely-related semiconductor optical amplifier (SOA) inside an EC to generate mode-locked pico-second lasing pulses [22], [23], and narrowlinewidth laser emission for atomic spectroscopy [14]. Nevertheless, combining InGaN-based SLDs with EC configurations has yet to be further explored for tunability and properties achieved herein.…”