Broadened Bandwidth Amplified Spontaneous Emission from Blue GaN-Based Short-Cavity Superluminescent Light-Emitting Diodes. (16th December 2019)

• Record Type: Journal Article
• Authors: Zhang, Hezhi; Shih, Ching-Wen; Martin, Denis; Caut, Alexander; Carlin, Jean-François; Butté, Raphaël; Grandjean, Nicolas
• Is Part Of: ECS journal of solid state science and technology. Volume 9:Number 1(2020)
• Publication Date: 2019-12-16
• Subjects: Semiconductors - III-V -- GaN -- lasers -- Superluminescent diodes; Solid state chemistry -- Periodicals; Electronics -- Materials -- Periodicals; Electrochemistry -- Periodicals; 541.0421
• DOI: 10.1149/2.0432001JSS
• Languages: English
• ISSNs: 2162-8777

Abstract

Abstract : We report broad bandwidth blue superluminescent light-emitting diodes (SLEDs) based on a short-cavity active region. The dependencies of amplified spontaneous emission (ASE) output power and gain bandwidth on cavity length were investigated in devices whose gain medium consists of a ridge waveguide with embedded InGaN/GaN quantum wells sandwiched between one etched facet coated with a high reflectivity distributed Bragg mirror and one cleaved facet with an anti-reflection coating. 250 μm-long blue SLEDs exhibit a spectral bandwidth up to 7.5 nm at 1.72 mW output power at a wavelength of 427 nm. As cavity length decreases, the bandwidth gradually broadens up to 15 nm for the shortest, 40 μm-long, SLED devices. ASE is confirmed by current-dependent electroluminescence spectra and polarization-dependent emission intensity measurements. The optical features of those short-cavity devices could be helpful for designing broad bandwidth SLEDs aiming for various applications such as optical coherence tomography, next generation displays, on-chip biosensing and imaging.