High-speed DFB laser and manufacturing method thereof

Abstract

The invention provides a high-speed DFB laser, and the epitaxial structure thereof comprises an InP substrate. A buffer layer is deposited on the InP substrate. A vertical confinement layer is deposited on the upper left of the buffer layer. A grating layer, a transition layer, a lower confinement layer in an active area, a lower waveguide layer, a quantum well, an upper waveguide layer and an upper confinement layer in the active area are deposited on the upper right of the buffer layer in order from bottom to top. The vertical confinement layer is aligned with the upper end of the upper confinement layer in the active area, and a corrosion barrier layer is deposited above the two layers. A coupling layer, a first barrier gradation layer, a first barrier gradation layer and an ohmic contact layer are sequentially deposited on the corrosion barrier layer. According to the invention, the laser has the advantages of low resistance, fast modulation rate and good lattice matching at high temperature, and is favorable for grating preservation; and during the growth process, pulsed airflow growth is used to grow a microscler nucleus layer first and then an epitaxial layer with a certainthickness, which is beneficial to improve the growth quality of the epitaxial layer.

Description

technical field [0001] The invention belongs to the technical field of DFB laser development, and in particular relates to a high-speed DFB laser and a manufacturing method thereof. Background technique [0002] As the 5G commercialization is approaching, the dynamic single-mode distributed feedback laser (DFB-LD) with narrow linewidth, high side mode suppression ratio and high modulation rate has become the preferred light source. DFB adopts grating modulation with periodically changing refractive index, has good single longitudinal mode characteristics, side mode suppression ratio can reach more than 35dB, and modulation rate can reach more than 50GHz, which can meet the application requirements of high speed / low delay of 5G mobile network. Since the 5G network is used outdoors, it is required to achieve a high modulation rate at -40 to 85°C. However, at high temperatures, the carrier leakage of the laser is serious, and the excessive hot phonons are easy to kick the carri...

AI Technical Summary

Problems solved by technology

These methods can obtain high-speed modulated DFB lasers, but some of these processes reduce the heat dissipation characteristics of the device while increasing the modulation bandwidth of the laser, for example: reducing the cavity length, that is, reducing the heat dissipation area of ​​the chip; using polymers instead of semiconductors as electrodes The support layer reduces the heat dissipation coefficient of the material, etc. These factors lead to the limitation of the bandwidth of the DFB laser when it works at high temperature

[0005] To this end, Macom uses a chip with a size of 200*250um, but in the ridge area of ​​the chip, part of the active area is etched away, and the cavity length of the chip is shortened without changing the heat dissipation area of ​​the chip to obtain a high-bandwidth DFB laser; In addition, Oclaro uses the InGaAsP waveguide layer to replace part of the active region to reduce the confinement factor and increase the bandwidth; however, because the quantum well material is a material containing Al, it is easy to oxidize and form defects during the etching and growth process, which easily leads to high-speed Lasers fail under high temperature operating conditions

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