Optical Module Asymmetric Laser Alignment for Coupling Efficiency
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Solution Overview
Problem
The existing optical modules with semiconductor lasers and waveguides face a decrease in optical coupling efficiency due to the large distance between the light-emitting point of the semiconductor laser and the incident surface of the waveguide, caused by the oblique arrangement of their surfaces, which also leads to increased return light beams affecting the resonance state of the semiconductor laser.
Innovation Solution
The optical module aligns the light-emitting point of the semiconductor laser with the core of the waveguide and arranges the emission and incident surfaces obliquely, with the light-emitting point positioned closer to the intersection of the extended lines of these surfaces than the center, reducing the distance and thereby enhancing optical coupling efficiency while minimizing return light beams.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the end surface of the substrate and the end surface of the waveguide are formed at different angles to reduce return light beams, then the optical coupling efficiency between the semiconductor laser and the waveguide decreases due to the increased distance between the light-emitting point and the incident surface
Solution Approach 1:
The patent applies local quality by differentiating the angular orientation of different surfaces. The emission surface of the semiconductor laser and the incident surface of the waveguide are arranged at different angles locally at their interfaces, while maintaining overall alignment. This localized angular differentiation reduces return light beams reflecting back into the laser cavity, while the local positioning of the light-emitting point ensures optimal coupling efficiency is maintained despite the angular mismatch.
2Object-affected harmful factors
If the light-emitting point is positioned at the center of the semiconductor laser width, then the return light beam is reduced, but the distance to the waveguide incident surface increases, reducing optical coupling efficiency
Solution Approach 1:
The patent applies asymmetry by positioning the light-emitting point off-center relative to the semiconductor laser width. Instead of symmetric center alignment, the light-emitting point is deliberately placed at an asymmetric position that is closer to one side. This asymmetric positioning reduces the distance to the waveguide incident surface, improving optical coupling efficiency, while the angular arrangement of surfaces compensates for potential return light issues.
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 configuration achieves high optical coupling efficiency and reduces return light beams, leading to improved luminous efficiency and suppression of resonance noise in the semiconductor laser, resulting in a reliable and efficient optical module.
Implementation Method 1
a semiconductor laser element (4)
Implementation Method 2
a planar lightwave circuit (PLC) in which a waveguide (10) is formed on a substrate (22)
Data Source
AI summary
There is provided an optical module comprising a semiconductor laser element; and a planar lightwave circuit (PLC) in which a waveguide is formed on a substrate. A position of a light-emitting point of the semiconductor laser element is approximately aligned with a position of a core of the waveguide. In a plan view, a first line segment representing an emission surface of the semiconductor laser element and a second line segment corresponding to the first line segment and representing an incident surface of the waveguide are arranged oblique to each other, and the light-emitting point of the semiconductor laser element is disposed closer to an intersection point of an extension line of the first line segment and the second line segment or an extension line of the second line segment than a center of the first line segment.