Planar semiconductor lasers using the photoelastic effect

Abstract

Planar separate-confinement, double-heterostructure, single-quantum-well photoelastic GaAs/AlGaAs lasers have been fabricated using a novel yet practical processing technique involving thin-film surface WNi stressors for waveguiding and ion implantation for isolation. A p++-GaAs contact layer regrown by chemical beam epitaxy has been used to improve the WNi ohmic contacts to the lasers. Even without bonding on heat sinks, these planar photoelastic lasers operate at continuous wave at room temperature. The lowest threshold is 29 mA for a cavity length of 178 μm and a stressor width of 5 μm. The internal quantum efficiency above threshold is 75%. The characteristic temperature is 114 K. The main waveguiding mechanism of the photoelastic lasers is determined to be weak index guiding with the beam waist in the junction plane measured 10 μm behind the end facet.

Photoelastic waveguides induced by a thin-film composite structure in InGaAsP/InP double heterostructures

“…Recently, a stable distribution of stress in AlGaAs/GaAs double heterostructures has been obtained by either metalsemiconductor interfacial reactions or rf sputtered refractory metal film with dc bias on the substrate [4]. By using this technique, planar photoelastic AlGaAs/GaAs quantum well lasers [5], photoelastic modulators [6] and planar photoelastic directional couplers [7] are created. Previously, Kirkby et al [3] proposed four possible configurations for producing a useful photoelastic waveguide: (i) a wide (more than 15 µm in width) stripe window in a film under compression, (ii) narrow (a few µm in width) stripes of film under compression, (iii) wide (more than 15 µm in width) stripes of film under tension and (iv) a narrow stripe (a few µm in width) window in a film under tension.…”

Stress-induced effects by the anodic oxide in ridge waveguide laser diodes

“…Recently, planar semiconductor lasers using the photoelastic waveguiding effect induced by a WNi stress layer were reported in [5]. Stress-induced lateral confinement of light in epitaxial BaTiO films was obtained by Barrios et al [6].…”