Annular-structure lower distributed Bragg reflector vertical cavity surface emitting semiconductor laser

Abstract

An annular-structure lower distributed Bragg reflector vertical cavity surface emitting semiconductor laser belongs to the technical field of semiconductor lasers. In the prior art, a light outlet hasprocess damages and is not easy to be well coupled with elements such as optical fibers and lenses, so the heat dissipation effect of the device needs to be improved. The laser sequentially comprisesan upper electrode, an ohmic contact layer, an upper distributed Bragg reflector, an oxide limiting layer, an active gain region, a lower distributed Bragg reflector, a substrate and a lower electrode from top to bottom; the upper electrode and the oxide limiting layer are in the shape of a ring with the same inner diameter, the width of the ring ranges from 3 micrometers to 5 micrometers, and the outer diameter of the ring ranges from 115 micrometers to 125 micrometers. A cylindrical hollow region exists in the central parts of the lower distributed Bragg reflector, the substrate and the lower electrode; the top face of the cylindrical hollow area is lower than the inner mirror face of the lower distributed Bragg reflector and higher than the outer mirror face of the lower distributed Bragg reflector, the diameter of the cylindrical hollow area ranges from 85 micrometers to 95 micrometers, and the cylindrical hollow area is filled with high-thermal-conductivity welding flux.

Description

technical field [0001] The invention relates to a vertical cavity surface-emitting semiconductor laser of a distributed Bragg reflector under a ring structure, belonging to the technical field of semiconductor lasers. Background technique [0002] Hollow Laser Beam (Hollow Laser Beam, HLB) is a ring-shaped beam with zero central light intensity in the direction of propagation, also known as hollow beam or dark hollow beam (Takahiro Kuga, Yoshio Torii, Noritsugu Shiokawa, et al.Novel OpticalTrapofAto6mswithaDoughnutBeam[J].PhysRevLett , 1997, 78:4713-4716). In other words, a hollow laser beam is a beam with zero optical axis intensity. Hollow beams have a series of novel and unique physical properties, such as barrel-shaped intensity distribution, small dark spot size (DSS), propagation invariance, and spin and orbital angular momentum. As a laser catheter, optical tweezers (optical tweezers) and optical wrench, the hollow beam becomes a powerful tool for precise manipulati...

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Problems solved by technology

[0004] However, in order to fabricate a distributed Bragg reflector with a ring structure in the existing vertical cavity surface emitting semiconductor laser, it is necessary to form the hollow part 10 by wet etching or dry etching, and to form the high resistance region 9 by hydrogen ion implantation, which It not only leads to more steps in the device manufacturing process, but also increases the difficulty of the process. For example, the depth of corrosion or etching is not easy to control, and the uniformity of ion implantation is not easy to grasp, which is not conducive to the mass production of devices.

The ensuing problems are at least the following four points: 1. The problem of process damage. Since the hollow part 10 is made on the side of the light outlet of the device, the wet etching or dry etching process will be distributed on the upper side. The outer mirror surface of the Bragg reflector 3 and the inner cylindrical surface of the laser ring cylindrical resonator cause damage, which can easily cause irreversible cavity structure damage, greatly reducing the device yield; at the same time, because the outer mirror surface of the upper distributed Bragg reflector 3 And the roughness of the inner cylindrical surface of the laser ring cylindrical resonator is increased, and the lasing light will be reflected in multiple steps, resulting in more stray light, which reduces the conversion efficiency of the injected current; 2. The quality of the hollow laser beam is difficult to guarantee, because The hydrogen ion implantation process is used to form the high-resistance region 9, but the uniformity of the implantation is not easy to grasp, resulting in that the light intensity in the center of the hollow laser beam is not absolutely zero, and the size of the dark spot is uncontrollable; 3. The problem of device packaging, due to the hollow part 10 Located on the side of the light outlet of the device, whether it is a single-tube package or an array package, it is very easy to cause mechanical damage to the cavity of the resonator, and it is difficult to improve the packaging process. For example, in the gold wire (making electrode leads) process, the upper distribution The Bragg reflector 3 bears too much stress per unit volume, which may easily cause mechanical damage to the cavity; for another example, in the array placement process, the contact area between the placement head and the array is small and the pressure is high, which may also easily cause mechanical damage to the cavity of the resonator; 4 1. Problems in the use of the device. Since the hollow part 10 is located on the side of the light outlet of the device, it is difficult to couple the device with optical components such as optical fibers and lenses in later practical applications, which limits the application range of the device.

[0005] Another problem is that all kinds of semiconductor lasers have common problems, that is, because the substrate material, such as GaAs, is a material with poor thermal conductivity, and the parts that play a role in heat dissipation, such as plate-shaped heat sinks, heat sinks, etc. The heat dissipation of the die is achieved through contact with the substrate, so the heat dissipation effect of the device needs to be improved

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