Semiconductor Laser Diode With Slant Mirror Surface Emission
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Solution Overview
Problem
Current semiconductor laser devices for short distance fiber optic transmission in the 1.3 μm wavelength band face challenges in achieving several mW optical power output while maintaining low power consumption and eliminating the need for optical isolators, which are costly and increase power consumption in long distance applications.
Innovation Solution
A short cavity laser operating in multiple longitudinal modes with a slant mirror structure that allows surface emission, reducing operation current and eliminating the need for optical isolators, while maintaining high optical output and response speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a short cavity laser operating in multiple longitudinal modes with slant mirror structure is used, then optical output power is improved and operation current is reduced, but device complexity increases due to the specialized cavity design
Solution Approach 1:
The laser cavity is segmented into distinct functional regions including the slant mirror section and the active region, allowing independent optimization of each segment. The slant mirror is positioned at a specific angle to redirect optical output while the active region maintains multiple longitudinal modes for high power output.
Solution Approach 2:
The slant mirror introduces asymmetric geometry to the otherwise symmetric laser cavity structure. This asymmetric design redirects the optical output at an angle rather than perpendicular to the cavity axis, enabling surface emission while maintaining the benefits of multiple longitudinal modes for high optical power.
2Ease of manufacture
If optical isolators are eliminated to reduce cost and power consumption, then module construction cost and power consumption are reduced, but reliability deteriorates due to potential reflected light interference
Solution Approach 1:
The slant mirror structure converts potentially harmful reflected light into a beneficial configuration by redirecting it away from the laser cavity at an angle. This geometric solution naturally prevents reflected light interference without requiring additional optical isolator components, thereby maintaining reliability while reducing cost and power consumption.
3Use of energy by moving object
If surface emitting laser structure is used to reduce power consumption, then power consumption is reduced, but manufacturing precision requirements increase to maintain single transverse mode operation
Solution Approach 1:
The laser operates in multiple longitudinal modes dynamically rather than being constrained to a single mode, which relaxes the manufacturing precision requirements for the emitting area. This dynamic multi-mode operation allows surface emission with lower power consumption while tolerating broader variations in emitting area dimensions.
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
The solution enables a low-cost, low-power-consuming laser device capable of emitting several mW optical power without increasing operation current, suitable for short distance fiber optic transmission, and reduces module construction costs by eliminating the need for optical isolators, while maintaining high performance and stability across temperatures.
Implementation Method 1
a slant mirror structure that allows surface emission
Implementation Method 2
A short cavity laser operating in multiple longitudinal modes
Data Source
AI summary
It is an object of the present invention to realize a low cost laser light source capable of emitting several mW optical power while the operation current is reduced. In particular, the present invention concerns a 1.3 μm wavelength band laser device suitable for several to several ten km short distance fiber optic transmission and also a less power consuming optical communication module in which such a laser is preferably mounted. As a laser structure which eliminates the necessity of adding an optical isolator by providing improved immunity to reflected light while lowering the operation current for less power consumption and not lowering the response speed, a short cavity laser which operates in multiple longitudinal modes is introduced. Especially, an angled mirror structure is formed at the laser's emitting edge to change the optical output direction so that the light is emitted from the top or bottom of the substrate.