GaSb-based mid-infrared circular spot output low divergence angle edge-emitting photonic crystal laser

Abstract

The invention provides a gallium stibino mid-infrared circular spot output low divergence angle edge photon emission crystal laser. The laser comprises an n type substrate, an n type electrode which is deposited on the reverse side of n type substrate, one-dimensional photonic crystals, a lower waveguide layer, an active layer, an upper waveguide layer, a p type cover layer, a ridge strip waveguide and a p type electrode, wherein the one-dimensional photonic crystals, the lower waveguide layer, the active layer, the upper waveguide layer, the p type cover layer, the ridge strip waveguide and the p type electrode are sequentially deposited on the front side of the n type substrate, and the ridge strip waveguide, the p type cover layer, the upper waveguide layer, the active layer, the lower waveguide layer, and the one-dimensional photonic crystals form a P-N knot. The alternating growth direction of the one-dimensional photonic crystals is perpendicular to the direction of the P-N knot, the direction of the ridge strip waveguide is parallel to the direction of the P-N knot, and the ridge strip waveguide and the one-dimensional photonic crystals form asymmetrical photonic crystal composite waveguides. The one-dimensional photonic crystals are imported to a ridge strip waveguide laser, and the mode perpendicular to the direction of the P-N knot can be regulated and controlled, so that the light field area of a ground mode is increased, and the far field divergence angle of the ground mode in the direction perpendicular to the P-N knot is reduced.

Description

technical field [0001] The invention relates to the technical field of semiconductor lasers, in particular to a gallium-antimony-based mid-infrared circular spot output low divergence angle edge-emitting photonic crystal laser. Background technique [0002] Compared with other lasers, semiconductor lasers have the advantages of high conversion efficiency, small size, light weight, high power, low threshold, and easy integration. Therefore, semiconductor lasers have been extensively studied by many research institutions. Semiconductor lasers operating in the mid-infrared band of 2-10 μm have shown great application potential in the fields of free-space optical communication, molecular spectroscopy, laser medical treatment, and infrared radar. Since the band gap of antimonide semiconductor materials can just cover this wavelength range, antimonide materials are the preferred materials for making mid-to-far infrared semiconductor lasers. [0003] From the first InGaAsSb / AlGaA...

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Problems solved by technology

[0005] In prior art ridge strip waveguide lasers, the thickness of the active layer perpendicular to the P-N junction direction is ultra-thin, only tens of nanometers. The problem caused by the ultra-thin active layer is the reduction of the optical confinement factor, so in this direction The beam waist size of the fundamental mode beam that is similar to Gaussian distribution is small

And because in the semiconductor laser, the far-field divergence angle of the light beam is inversely proportional to the beam waist size produced by the active layer of the laser, so the very small beam waist produced in the active layer perpendicular to the P-N junction direction causes the far field in this direction. Large field emission angle

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