A high-speed semiconductor laser with beam-diffusion structure

Abstract

The invention discloses a semiconductor laser, which comprises an optical waveguide structure, and the optical waveguide structure comprises a lower waveguide layer (2), a multi-quantum well active layer (3) and an upper waveguide layer (5) stacked sequentially from bottom to top ), a grating layer (4) is formed on the upper part of the multi-quantum well active layer (3), and the upper waveguide layer (5), cladding layer 6 and contact layer 7 are formed as raised ridges, and the raised ridges have The light-incident end face and the light-out end face have a beam diffusion structure on one side of the light-out end face. The beam diffusing structure has a beam expanding portion, and the beam expanding portion has a shape that gradually shrinks inwardly from the light emitting end face. The horizontal divergence angle of the beam expanding part is preferably 5°-20°. The invention can well suppress the diffusion of light in the horizontal direction, improve the beam quality, achieve better mode matching with the optical fiber, increase the output power of the laser, and improve the high-frequency response characteristics of the laser.

Description

technical field [0001] The invention belongs to the technical field of semiconductors, and in particular relates to a high-speed semiconductor laser with a beam diffusion structure on the light-emitting end face. Background technique [0002] High-speed semiconductor lasers are the core devices of high-speed communication systems. The high-performance transmitter uses a high-power, low-noise DFB laser as a light source, and realizes data loading through direct modulation or external modulation. External modulation technology can achieve a wide modulation frequency range (>75GHz), but there are also some shortcomings, such as large volume, high cost, high driving voltage, and large insertion loss (6-7dB). Directly modulated semiconductor laser superimposes the modulation signal on the DC bias current, which can modulate the amplitude of the laser output optical signal. It is a method to achieve high-efficiency light emission. and other unique advantages. [0003] Direct...

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Problems solved by technology

However, increasing the injection current will easily cause irreversible damage to the end face of the laser, or even burn the semiconductor laser

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