CN-122026223-A - InP-based optical communication laser high-speed modulation stability improving process and laser

CN122026223ACN 122026223 ACN122026223 ACN 122026223ACN-122026223-A

Abstract

The invention provides a high-speed modulation stability improving process of an InP-based optical communication laser and the laser, which relate to the technical field of laser processes, the method comprises the steps of epitaxial wafer preparation, distributed feedback grating and quarter wavelength phase shift region formation, ridge main active strip etching, two-side long and narrow injection window opening, dual-energy proton injection, rapid thermal annealing, fe-doped InP semi-insulating embedded current limiting structure formation and coplanar waveguide electrode preparation, and carrier pressure relief galleries with central regions, transition regions and end regions longitudinally distributed are constructed on two sides of the main active strips. The structure enables excessive carriers in the main active region to enter the deep energy level defect region through the un-injected connection region and generate non-radiative recombination during high-speed direct modulation, reduces carrier space peak value, refractive index disturbance and output optical power fluctuation, improves high-speed modulation stability, is suitable for high-speed optical communication emission devices, and gives consideration to single-mode output and wide-temperature working reliability.

Inventors

ZHOU SHAOFENG
DING LIANG
HUANG LIANGJIE
LUO JUNBO
Lv tianjian
FANG ZIXUN

Assignees

深圳市星汉激光科技股份有限公司

Dates

Publication Date: 20260512
Application Date: 20260415

Claims (10)

1. The high-speed modulation stability improving process for the InP-based optical communication laser is characterized by comprising the following steps of: sp1, providing an InP-based laser epitaxial wafer, wherein the epitaxial wafer is sequentially provided with an n-type InP substrate, an n-type InP lower cladding layer, a lower waveguide limiting layer, a multiple quantum well active layer, an upper waveguide limiting layer, a p-type InP upper cladding layer and a p-type contact layer from bottom to top; sp2, forming a distributed feedback grating on the epitaxial wafer, and forming a quarter-wavelength phase shift region in the distributed feedback grating; Sp3, etching along the length direction of the laser cavity to form a ridge-shaped main active strip; sp4, forming long and narrow injection windows extending along the cavity length direction at shoulder regions at two sides of the ridge-shaped main active strip; sp5, carrying out proton implantation on the two side areas of the ridge-shaped main active strip through the long and narrow injection window, forming carrier pressure release galleries on the two sides of the ridge-shaped main active strip, wherein deep energy level defect areas are arranged in the carrier pressure release galleries, and non-injection connection areas are arranged between the deep energy level defect areas and the main active areas; sp6, carrying out annealing treatment on the structure after proton implantation, and fixing the position and defect density of the deep energy level defect area; sp7, forming embedded current limiting structures on two sides of the ridge-shaped main active strip; sp8, forming a coplanar waveguide electrode structure on the p-type contact layer; The deep energy level defect region is provided with a central region, a transition region and end regions along the length direction of a laser cavity, the central region is positioned in a quarter-wavelength phase shift region and cavity length sections at two sides of the quarter-wavelength phase shift region, the defect density of the central region is larger than that of the transition region, the defect density of the transition region is larger than that of the end regions, and excessive carriers in a main active region enter the carrier pressure release gallery through transverse diffusion and local electric field driving and non-radiative recombination when the laser is in a high-speed direct modulation state, so that carrier swing of the main active region is reduced and high-speed modulation stability is improved.
2. The high-speed modulation stability enhancement process of an InP-based optical communication laser according to claim 1, wherein said lower waveguide confinement layer and said upper waveguide confinement layer are both separate confinement heterostructure waveguide confinement layers, said multiple quantum well active layer is located between said lower waveguide confinement layer and said upper waveguide confinement layer, said deep energy level defect region is located in said upper waveguide confinement layer and said p-type InP upper cladding layer, and said non-implanted connection region is formed by upper waveguide confinement layer continuous portions on both sides of said ridge-shaped main active stripe.
3. The process of claim 1, wherein the proton implantation in Sp5 comprises a first proton implantation and a second proton implantation, the first proton implantation forms a first defect layer in the p-type InP upper cladding layer, the second proton implantation forms a second defect layer in the upper waveguide confinement layer, the first defect layer and the second defect layer are in vertical communication to form the deep level defect region, and no defect peak region is formed in the multi-quantum well active layer.
4. The InP-based optical communication laser high-speed modulation stability enhancement process of claim 1, wherein said central region has a length along the cavity length of twenty-fifty percent of the total cavity length of the laser, said transition region has a total length along the cavity length of twenty-forty percent of the total cavity length of the laser, and said end regions have a total length along the cavity length of twenty-forty percent of the total cavity length of the laser.
5. The process for improving the high-speed modulation stability of an InP-based optical communication laser according to claim 1, wherein the annealing treatment in Sp6 is rapid thermal annealing at a temperature of three hundred fifty degrees celsius to five hundred degrees celsius for ten seconds to one hundred twenty seconds.
6. The process of claim 1, wherein the buried current confinement structure in Sp7 is formed of Fe-doped InP semi-insulating material, and the buried current confinement structure is located on two sides of the ridge-shaped main active stripe.
7. The InP-based optical communication laser high-speed modulation stability enhancement process according to claim 1, wherein the lateral width of the non-injected connection region is zero one micron to zero eight microns, the lateral width of the carrier relief gallery is zero five microns to three microns, and the defect density of the deep level defect region and the lateral width of the non-injected connection region together define a lateral carrier relief path from the main active region to the carrier relief gallery.
8. The laser prepared based on the high-speed modulation stability improvement process of the InP-based optical communication laser according to any one of claims 1 to 7, wherein the InP-based optical communication laser is composed of an n-type InP substrate, an n-type InP lower cladding layer, a lower waveguide confinement layer, a multiple quantum well active layer, an upper waveguide confinement layer, a p-type InP upper cladding layer, a p-type contact layer, a distributed feedback grating, a quarter-wavelength phase shift region, a ridge-shaped main active stripe, a carrier gallery, a buried current confinement structure, and a coplanar waveguide electrode structure; The distributed feedback grating and the quarter-wavelength phase shift region are arranged in a waveguide region corresponding to the multiple quantum well active layer; the ridge-shaped main active strip extends along the length direction of the laser cavity; the carrier pressure release gallery is arranged on two sides of the ridge-shaped main active strip; A deep energy level defect area is arranged in the carrier pressure release gallery; An un-injected connection region is arranged between the deep energy level defect region and the main active region; The deep energy level defect area is provided with a central area, a transition area and an end area along the length direction of the laser cavity; the central region is positioned in the quarter-wavelength phase shift region and the cavity length sections at the two sides of the central region; the defect density of the central area is greater than that of the transition area; The transition region has a defect density greater than the defect density of the end region.
9. The laser of claim 8, wherein the deep level defect region is located in the upper waveguide confinement layer and the p-type InP upper cladding layer, the non-implanted connection region is formed by continuous portions of the upper waveguide confinement layer on both sides of the ridge-shaped main active stripe, and the buried current confinement structure is formed outside the carrier relief gallery by using an Fe-doped InP semi-insulating material.
10. The InP-based optical communication laser according to claim 8, wherein said coplanar waveguide electrode structure is disposed above said p-type contact layer, and said carrier decompression gallery extracts excess carriers Shi Cexiang in the main active region and combines them nonradiatively in a high-speed direct modulation state, so as to reduce the peak value of the carrier spatial distribution in the main active region and reduce the output optical power fluctuation during high-speed modulation.

Description

InP-based optical communication laser high-speed modulation stability improving process and laser Technical Field The invention relates to the technical field of laser processes, in particular to a high-speed modulation stability improving process of an InP-based optical communication laser and the laser. Background The InP-based optical communication laser has the advantages of a material system suitable for one-point three-one-micron wave band and one-point five-micron wave band operation, and is widely applied to data center interconnection, access network transmission, mobile communication forwarding and medium-short distance single mode fiber links. In the prior application, in order to meet the requirements of high speed, low cost and miniaturization, a direct modulation distributed feedback laser is one of important schemes. The device generally realizes single longitudinal mode output through a distributed feedback grating, realizes current constraint through a ridge waveguide and a buried current limiting structure, and completes large-bandwidth radio frequency driving through a high-speed electrode. However, the existing InP-based direct modulation laser still has the problem of insufficient stability under the high-speed modulation state. The main active region is easy to generate excessive carrier accumulation under the conditions of high-speed rising edge, large modulation swing and high-temperature bias, so that the carrier spatial distribution has obvious peak value, and further dynamic spatial hole burning, local refractive index rapid swing, mode stability reduction and output optical power fluctuation increase are caused. Especially in the vicinity of the quarter-wavelength phase shift region, local carrier consumption and the complementary process are more nonuniform due to higher photon density, which is liable to cause eye opening deterioration, side mode suppression ratio decrease, chirp increase and modulation performance degradation under high temperature conditions. In the prior art, the high-speed performance is generally improved by optimizing the grating coupling coefficient, reducing the parasitic capacitance, improving the heat dissipation structure or enhancing the embedded current limiting capability, but the mode is mainly aimed at optimizing the static structure parameter or the external parasitic parameter of the device, and the excessive carriers in the main active region are difficult to actively dredge in the high-speed modulation process, so that the device still easily has the problem of insufficient dynamic stability under the working conditions of high bit rate, large swing and wide temperature. Based on this, it is necessary to propose a high-speed modulation stability improvement process for InP-based optical communication lasers capable of implementing selective lateral extraction and non-radiative recombination of excess carriers during high-speed modulation without significantly damaging the gain of the main active region, so as to improve the high-speed modulation stability, single-mode output capability and wide-temperature operational reliability of the devices in an actual communication system. Disclosure of Invention Technical problem to be solved Aiming at the defects of the prior art, the invention provides a high-speed modulation stability improving process of an InP-based optical communication laser and the laser, and solves the problems of the prior art. Technical proposal In order to achieve the purpose, the invention is realized by the following technical scheme that the high-speed modulation stability improvement process of the InP-based optical communication laser comprises the following steps: sp1, providing an InP-based laser epitaxial wafer, wherein the epitaxial wafer is sequentially provided with an n-type InP substrate, an n-type InP lower cladding layer, a lower waveguide limiting layer, a multiple quantum well active layer, an upper waveguide limiting layer, a p-type InP upper cladding layer and a p-type contact layer from bottom to top; sp2, forming a distributed feedback grating on the epitaxial wafer, and forming a quarter-wavelength phase shift region in the distributed feedback grating; Sp3, etching along the length direction of the laser cavity to form a ridge-shaped main active strip; sp4, forming long and narrow injection windows extending along the cavity length direction at shoulder regions at two sides of the ridge-shaped main active strip; sp5, carrying out proton implantation on the two side areas of the ridge-shaped main active strip through the long and narrow injection window, forming carrier pressure release galleries on the two sides of the ridge-shaped main active strip, wherein deep energy level defect areas are arranged in the carrier pressure release galleries, and non-injection connection areas are arranged between the deep energy level defect areas and the main active areas; sp6, carrying out annealing treatment on