Vertical cavity surface emitting laser with high modulation bandwidth

Abstract

The invention discloses a high-modulation bandwidth vertical cavity surface emitting laser which comprises a substrate layer, a lower DBR layer, an active area, an oxidation limiting layer, an upper DBR layer and a P-type electrode at the uppermost end from bottom to top, an N-type electrode is laid on the lower DBR layer, the active area is composed of a strained quantum well and a barrier layer, and the growth crystal orientation of the strained quantum well is the (110) direction of the substrate layer. According to the vertical cavity surface emitting laser disclosed by the invention, the strained quantum well grows in the (110) direction, so that splitting between a heavy hole band and a light hole band can be intensified, the effective mass of a valence band of the strained quantum well is minimized, the asymmetry of a conduction band and a valence band structure is reduced, the number of reversal particles required during lasing of the laser is reduced, and the laser efficiency is improved. Furthermore, the differential gain of the active region can be obviously improved during lower carrier injection; therefore, the modulation bandwidth and the modulation rate of the vertical-cavity surface-emitting laser device are improved, and the vertical-cavity surface-emitting laser device has more excellent high-speed direct modulation performance.

Description

technical field [0001] The invention relates to a vertical cavity surface emitting laser, in particular to a vertical cavity surface emitting laser with high modulation bandwidth. Background technique [0002] Vertical cavity surface emitting laser (VCSEL) has the advantages of low cost, low threshold, high speed and low power consumption, and has become the core light source of short-distance optical interconnection, and its main wavelength is 850nm band. With the development of data centers and optical fiber access networks, the demand for short-distance optical interconnection performance is getting higher and higher. In order to reduce costs as much as possible, such systems generally use directly modulated semiconductor lasers as light sources to save the additional complexity and corresponding costs brought about by external modulators. However, the inherently lower relaxation oscillation frequency of directly modulated vertical cavity surface emitting lasers limits i...

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Problems solved by technology

However, the degree of freedom to further increase the differential gain of the active region in the current common vertical cavity surface emitting laser is very small, which also limits the further improvement of the small signal modulation bandwidth and modulation rate of the semiconductor laser.

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