Laser with far-field divergence angle in narrow vertical direction and fabrication method of laser

Abstract

The invention provides an epitaxial structure of a laser. The epitaxial structure comprises a InP substrate, wherein a buffer layer, an N-type external limitation layer, an N-type internal limitation layer, a non-doping waveguide layer with graded refractive index, a quantum well active region, a non-doping waveguide layer with graded refractive index, a P-type internal limitation layer, a P-type external limitation layer, a corrosion blocking layer, a P-type wrapping layer, a P-type barrier gradually-changing layer, a P-type barrier abruptly-changing layer and a P-type ohmic contact layer are sequentially deposited on the InP substrate from bottom to top, wherein the pairs of quantum wells of the quantum well active region are not less than six, the quantum wells are of stress quantum well structures, wells are press stress, barriers are tension stress, the thickness of the barriers of the quantum well structures are not smaller than 10 nanometers, and the N-type internal limitation layer is a tension stress structural layer and employs a AlInAs material. By the laser, a far-field divergence angle of a semiconductor laser in a vertical direction can be reduced, and the coupling efficiency of the laser and an optical fiber is improved.

Description

technical field [0001] The invention relates to the technical field of semiconductor lasers, in particular to a laser with a narrow vertical far-field divergence angle and a preparation method for the laser. Background technique [0002] Semiconductor lasers have the characteristics of small size, light weight, low threshold, long life, and compatibility with silicon integrated circuits. They are the main light sources for optoelectronic integrated circuits such as optical communication, optical interconnection, and optical computing. In these applications, the light emitted by the semiconductor laser often needs to use optical fiber as the transmission medium, which requires a high coupling efficiency between the laser and the optical fiber. However, the traditional semiconductor laser uses a multi-quantum structure as the active layer, and the width of the optical cavity is often Only a few hundred nanometers, the vertical far-field light emission angle is about 32-45°, wh...

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Problems solved by technology

However, the introduction of the heteroepitaxial layer will not only increase the carrier injection barrier, but also introduce parasitic capacitance, which will affect the threshold, power and spectral response curve of the semiconductor laser, so the improvement effect is not ideal

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