Laterally-coupled distributed feedback laser with first-order gratings by interference lithography

• Published in: Electronics letters Vol. 49; no. 12; pp. 764 - 766
• Main Authors: Li, Jingsi, Cheng, Julian
• Format: Journal Article
• Language: English
• Published: Stevenage The Institution of Engineering and Technology 06.06.2013; Institution of Engineering and Technology
• Subjects: aluminium compounds; Applied sciences; cavity length; current density; deep ridge‐waveguide structure; depth 2 mum; DFB ridge‐waveguide lasers; dielectric mask; diffraction gratings; distributed feedback lasers; Electronics; etching; Exact sciences and technology; first‐order sidewall gratings; Fundamental areas of phenomenology (including applications); gallium arsenide; Gratings; III‐V semiconductors; indium compounds; InP‐AlGaInAs; laser beams; laser cavity resonators; laser epiwafer; laser modes; Lasers; laterally‐coupled distributed feedback laser; light interference; masks; Microelectronic fabrication (materials and surfaces technology); Optical elements, devices, and systems; optical fabrication; optical interference lithography; Optics; photolithography; Photonics; Physics; planar top surface; quantum well lasers; ridge waveguides; self‐aligned process; Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices; semiconductor epitaxial layers; Semiconductor lasers; laser diodes; sidemode suppression ratio; single longitudinal mode continuous‐wave operation; size 2.6 mum; size 300 nm; size 650 mum; slope efficiency; temperature 293 K to 298 K; threshold current density; uncoated facets; waveguide lasers; uncoated facets; laser cavity resonators; depth 2 mum; indium compounds; waveguide lasers; aluminium compounds; size 300 nm; self-aligned process; ridge waveguides; laser beams; DFB ridge-waveguide lasers; laser epiwafer; first-order sidewall gratings; single longitudinal mode continuous-wave operation; distributed feedback lasers; sidemode suppression ratio; gallium arsenide; laser modes; size 650 mum; dielectric mask; etching; planar top surface; current density; light interference; InP-AlGaInAs; masks; optical interference lithography; diffraction gratings; quantum well lasers; laterally-coupled distributed feedback laser; photolithography; deep ridge-waveguide structure; slope efficiency; threshold current density; cavity length; semiconductor epitaxial layers; optical fabrication; temperature 293 K to 298 K; III-V semiconductors; size 2.6 mum; Light interferometry; Dielectric materials; Lithography; Diffraction gratings; Longitudinal wave; Indium phosphide; Ridge waveguides; Alignment; Continuous wave; Laser cavities; Current density; Distributed feedback lasers; Threshold
• ISSN: 0013-5194; 1350-911X; 1350-911X
• DOI: 10.1049/el.2013.1520

The first laterally-coupled distributed feedback (DFB) laser with first-order sidewall gratings fabricated by optical interference lithography is experimentally demonstrated. The gratings were first etched into a dielectric mask on the planar top surface of an InP/AlGaInAs laser epiwafer, and then transferred to both sidewalls of a 2 µm deep ridge-waveguide structure using a novel self-aligned process. DFB ridge-waveguide lasers with a cavity length of 650 µm and width of 2.6 µm (with 300 nm gratings on both sidewalls) achieved single longitudinal mode continuous-wave operation, with a sidemode suppression ratio of 37 dB. The threshold current density is 1.7 kA/cm2 at room temperature, and the slope efficiency is 0.14 mW/mA per facet (uncoated).