High-speed semiconductor laser with beam diffusion structure

Abstract

The invention discloses a semiconductor laser, comprising an optical waveguide structure, wherein the optical waveguide structure comprises a lower waveguide layer (2), a MQW (multiple quantum wells) active layer (3) and an upper waveguide layer (5), which are overlapped in sequence from bottom to top; a grating layer (4) is formed at the upper part of the MQW active layer (3); the upper waveguide layer (5), a wrapping layer 6 and a contact layer 7 form a ridge; the ridge is provided with an incident end face and an emergent end face and has a beam diffusion structure at the side of the emergent end face; the beam diffusion structure has a beam diffusion part which is of a shape gradually shrinking from the emergent end face to the inside; the horizontal divergence angle of the beam diffusion part is 5 DEG-20 DEG preferably. The semiconductor laser can restrain the light diffusion in the horizontal direction and improve the quality of a beam so that better mode matching between the beam and optical fibers can be achieved; the output power of the laser can be enhanced and the high-frequency response characteristic of the laser can be improved.

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 surface. 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] Dir...

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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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