Monolithic integrated laser chip with direct modulation bandwidth extension based on amplified feedback

Abstract

A monolithic integrated laser chip that realizes direct modulation bandwidth expansion based on amplification feedback, comprising: a lower confinement layer; an active layer fabricated on the lower confinement layer; an upper confinement layer fabricated on the active layer; a waveguide layer, which is strip-shaped, and is longitudinally fabricated in the middle of the upper confinement layer; a P+ electrode layer, which is divided into three sections by an isolation ditch, is fabricated on the waveguide layer; an N+ electrode layer, which is fabricated on the lower confinement layer The back side of the layer; the P+ electrode layer divided into three sections corresponds to the DFB laser area, the passive phase adjustment area and the active amplification feedback area respectively, and the upper confinement layer corresponding to the DFB laser area is made with a distributed feedback Bragg grating layer; There is a 90nm blue shift in the gain peak of the active layer corresponding to the passive phase adjustment area and the active layer corresponding to the DFB laser area and the active amplification feedback area. The invention can break through the limitation of the direct modulation bandwidth of the common laser chip, and realize the expansion of the direct modulation bandwidth of the laser with an ingenious, effective and low-cost method.

Description

technical field [0001] The invention relates to the field of semiconductor optoelectronics, in particular to a monolithic integrated laser chip that realizes direct modulation bandwidth expansion based on amplification feedback. Background technique [0002] In the current optical communication system, large-capacity data is transmitted using light, while the storage and processing of signals are still electrical media. The process of loading high-speed electrical signals onto light waves through high-speed modulators or light sources is modulation. modulation. The two main modulation methods are direct modulation and external modulation. The former modulates the light intensity by changing the magnitude of the laser injection current, and the latter uses an external optical modulator to modulate the continuous light emitted by the semiconductor laser. Externally modulated transmitters are the main solution for medium and long-distance Dense wavelength division multiplexing...

AI Technical Summary

Problems solved by technology

However, the feedback area of ​​this structure only contains a phase adjustment area, and there is no additional feedback intensity adjustment area, which makes the adjustment range of the feedback intensity very limited

This will greatly limit the practical use of lasers. After all, a suitable feedback strength directly determines whether the device can achieve bandwidth expansion.

At the same time, for this structure, if we need to find a specific optical-optical response oscillation peak (bandwidth extension peak), we need to accurately select the laser chip cavity length, which will increase the workload and cost

And in practice, we have also tested a large number of chips with DFB laser region plus passive phase region structure, and the result is that it is difficult to find the phenomenon of direct modulation bandwidth expansion

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