Optical Receiver Module Beam Waist Positioning for Coupling Efficiency
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Solution Overview
Problem
Existing optical receiver modules face inefficiencies in optical coupling due to varying optical paths for different wavelength signals, leading to discrepancies in coupling efficiency, especially when the coupling fiber is aligned at the focal point of the first lens, resulting in non-collimated beam profiles and reduced efficiency for some signal lanes.
Innovation Solution
The optical receiver module positions the beam waist of the wavelength-multiplexed signal midway between the longest and shortest optical paths, achieved by setting the coupling fiber slightly offset from the focal point of the first lens, ensuring a quasi-collimated beam and minimizing differences in beam diameters across lanes, thus optimizing coupling efficiency for all signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the coupling fiber is aligned at the focal point of the first lens, then the beam is collimated, but the optical paths for different wavelength signals vary significantly causing coupling efficiency discrepancies
Solution Approach 1:
The patent changes the position parameter of the coupling fiber from the focal point to an offset position. Specifically, the coupling fiber is positioned at a distance from the first lens that is longer than the focal length, which transforms the beam from fully collimated to quasi-collimated. This parameter change balances the optical paths for different wavelength signals, reducing path length differences and improving coupling efficiency uniformity across all signal lanes while maintaining adequate collimation.
2Quantity of substance
If the beam waist is positioned at the focal point, then maximum concentration is achieved, but beam diameter discrepancies across lanes increase reducing overall efficiency
Solution Approach 1:
The patent applies local quality by positioning the beam waist at a specific location that is not at the focal point but rather at an offset position. The beam waist is formed at a distance from the first lens that is longer than the focal length, creating a quasi-collimated beam with optimized local properties. This positioning ensures that beam diameters across different lanes are more uniform while maintaining sufficient concentration for efficient coupling.
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 enhances coupling efficiency across all signal lanes, with maximum efficiency for some lanes exceeding 95%, while maintaining high efficiency for others, by averaging the optical path distances and reducing beam diameter discrepancies, thereby improving overall signal processing performance.
Implementation Method 1
a first lens (18) that receives and concentrates the wavelength-multiplexed signal as forming a beam waist
Implementation Method 2
an optical de-multiplexer (26) that de-multiplexes the wavelength-multiplexed signal into the optical signals depending on the wavelengths
Implementation Method 3
second lenses (28) that concentrate the optical signals output from the optical de-multiplexer
Implementation Method 4
photodiodes (29) that receive the optical signals output from the second lenses
Data Source
AI summary
An optical receiver module that receives a wavelength-multiplexed optical signal is disclosed. The optical receiver module includes a first lens, an optical de-multiplexer, second lenses, and photodiodes. The first lens forms a beam waist of the wavelength-multiplexed optical signal output therefrom. The optical de-multiplexer de-multiplexes the wavelength-multiplexed optical signal into optical signals depending on wavelengths thereof and is installed so as to make optical paths for respective optical signals different from each other. The second lenses concentrate the optical signals onto the respective photodiodes. In the optical receiver module, the beam waist of the wavelength-multiplexed optical signal is set in a halfway between a longest path and a shortest path from the first lens to the second lenses.