Ridge-shaped laser structure and surface etched grating semiconductor laser with periodic pumping
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Solution Overview
Problem
Traditional distributed feedback semiconductor lasers have high manufacturing costs, low yield, and poor reliability.
Innovation Solution
A ridge-shaped laser structure with a surface etched grating and periodic pumping, featuring a grating structure with periodically spaced grooves and electrical contact regions, where carriers injected through a top electrode layer flow through these grooves and laterally diffuse to a multiple quantum well active layer, creating uniform carrier distribution and gain modulation, with a preset phase relationship between refractive index and gain modulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional distributed feedback semiconductor lasers are used, then feedback mechanism is achieved, but manufacturing cost is high and yield is low
Solution Approach 1:
The laser structure is segmented into distinct functional layers: lower doped dielectric layer, multiple quantum well active layer, ridge-shaped doped dielectric layer, grating structure, and top electrode layer. This segmentation allows each layer to be optimized independently for its specific function, simplifying the manufacturing process while maintaining laser performance and reliability.
Solution Approach 2:
Different regions of the laser structure have different doping concentrations and material compositions tailored to their specific functions. The lower doped dielectric layer has different properties than the ridge-shaped doped dielectric layer, which in turn differs from the multiple quantum well active layer. This local quality optimization enables reliable laser operation with simplified manufacturing compared to traditional uniform structures.
2Reliability
If traditional distributed feedback semiconductor lasers are used, then feedback mechanism is achieved, but manufacturing complexity increases
Solution Approach 1:
The device is divided into discrete layers that can be fabricated using standard semiconductor processing techniques. Each layer (lower doped dielectric layer, multiple quantum well active layer, ridge-shaped doped dielectric layer, grating structure, top electrode layer) can be deposited, patterned, and etched independently, reducing overall manufacturing complexity while ensuring reliable device performance.
Solution Approach 2:
The feedback mechanism is achieved through a surface etched grating structure that introduces periodicity in the spatial dimension, rather than requiring complex internal cavity structures. This dimensional approach simplifies the manufacturing process by using standard photolithography and etching techniques to create the grating pattern on the ridge-shaped doped dielectric layer.
3Power
If carriers are injected through top electrode layer, then pumping is achieved, but uniform carrier distribution is difficult to maintain
Solution Approach 1:
The ridge-shaped doped dielectric layer has a specific doping profile and geometric shape that creates localized electric field distributions. When carriers are injected through the top electrode layer, the ridge structure guides and distributes them uniformly across the active region. The local doping concentration and ridge geometry are optimized to ensure uniform carrier distribution while maintaining efficient pumping.
Solution Approach 2:
By adjusting the doping concentration, ridge width, and depth of the ridge-shaped doped dielectric layer, the carrier distribution uniformity can be optimized. These parameter changes allow the structure to maintain uniform carrier density across the active region under different injection current conditions, improving both pumping efficiency and manufacturing tolerance.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This design improves laser performance and stability, increases yield, and reduces manufacturing costs by ensuring uniform carrier distribution and tailored modulation intensities, enhancing reliability and efficiency.
Implementation Method 1
A distributed feedback laser has two mechanisms to achieve feedback, which are periodic refractive index modulation and periodic gain (loss) modulation.
Implementation Method 2
A distributed feedback laser has two mechanisms to achieve feedback, which are periodic refractive index modulation and periodic gain (loss) modulation.
Implementation Method 3
Ohmic electrical contact is formed between the top electrode layer and a top surface of each of the electrical contact regions, such that carriers injected through the top electrode layer flow downward through the electrical contact regions and the ridge-shaped doped dielectric layer in turn
Implementation Method 4
An insulating layer at least covering sidewalls of each grating grooves is formed in each of the grating grooves
Data Source
AI summary
Disclosed is a surface etched grating semiconductor laser with periodic pumping structure. The structure includes a lower doped dielectric layer, a multiple quantum well active layer, a ridge-shaped doped dielectric layer, periodic grating grooves formed on the ridge-shaped doped dielectric layer and a top electrical contact layer forming ohmic electrical contact with electrical contact regions between the grating grooves. Carriers are injected through the periodic electrical contact layer, flow through the electrical contact regions, spread laterally when reaching the bottom of the grating grooves, and then continue to spread to the multiple quantum well active layer. In a case of uniform distribution, a laser based on refractive index modulation is realized. In a case of non-uniform distribution, a laser with mixed modulation is realized by introducing additional gain modulation.