Optical Receptacle Filter Integration for Large Core Fiber Coupling
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Solution Overview
Problem
The existing optical transmission modules face challenges with reduced light coupling efficiency due to the lengthened light path and incomplete collimation when using optical fibers with large core diameters, leading to increased module size and return light interference.
Innovation Solution
An optical receptacle with a specific configuration, including first, second, and third optical surfaces, and a reflecting surface, is used to optimize light coupling efficiency by adjusting the central axes and filter surfaces to minimize return light and maintain high coupling efficiency, even with large core optical fibers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a filter mounting part and reflecting surface are provided spaced from each other in the optical member, then the optical filter can be installed, but the light path lengthens and module size increases
Solution Approach 1:
The filter mounting surface and reflecting surface are merged into a single integrated structure on the optical member. The filter is mounted on this surface and the reflecting surface is formed in the same plane, eliminating the need for spaced separate components. This integration maintains a compact light path while providing both filter installation capability and light reflection functionality.
2Speed
If the lens for fiber is used to collimate light, then light direction is controlled, but complete collimation is not achieved with large core diameter fibers
Solution Approach 1:
The optical receptacle is designed with specific geometric parameters including a light-receiving surface area of 100 μm² or more and a light-emitting surface area of 50 μm² or more. The distance between these surfaces is controlled to be 10 μm or more but less than the diameter of the light-receiving surface. These parameter adjustments optimize light coupling efficiency for large core diameter fibers without requiring complete collimation.
3Ease of manufacture
If the central axis of the lens for transmission coincides with the light axis of the optical element for transmission, then optical alignment is simplified, but return light reaches the optical element and disturbs intensity distribution
Solution Approach 1:
The harmful return light path is extracted and redirected away from the optical element for transmission. The reflecting surface is positioned and angled to reflect transmission light toward the light-receiving element rather than back to the optical element for transmission. This separates the useful light path from the harmful return light path, eliminating interference while maintaining alignment simplicity.
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 effectively maintains high light coupling efficiency and reduces return light interference, ensuring efficient communication even with large core optical fibers, while allowing for compact module design.
Implementation Method 1
an optical filter that reflects, toward the lens for fiber, the signal light entered from the lens for transmission, or allows, to pass therethrough, the reception light entered from the lens for fiber
Implementation Method 2
a reflecting surface that reflects, toward the lens for reception, the reception light passed through the optical filter
Implementation Method 3
a lens for fiber disposed to face the optical fiber
Data Source
AI summary
An optical receptacle includes an optical receptacle main body and a filter. The optical receptacle main body includes a first optical surface, a second optical surface, a third optical surface, and a reflecting surface. The filter includes a first filter that reflects light of a first wavelength and allows light of a second wavelength to pass therethrough, and a second filter that reflects the light of the second wavelength and allows the light of the first wavelength to pass therethrough. The filter is disposed on the optical receptacle main body such that the first filter or the second filter makes intimate contact with the reflecting surface. A second central axis of the second optical surface do not coincide with a light axis of a light-receiving element. A third central axis of the third optical surface do not coincide with a light axis of a light-emitting element.