Asymmetric Prism Wavelength Multiplexing for Compact Optical Path
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Solution Overview
Problem
Conventional optical communication apparatuses face challenges in achieving a sufficient optical path changing angle while minimizing the angle of incidence of the filter, which is crucial for compact design and optimal transmission characteristics, especially in WDM systems where wavelength differences are small.
Innovation Solution
The design incorporates a prism with a non-parallel front and rear end face, where the wavelength filter film is placed on the rear end face to reflect one laser beam and transmit the other, allowing for independent adjustment of the prism angle to maintain a constant optical path changing angle while reducing the angle of incidence of the filter.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional parallel flat prism or triangular prism is used for wavelength filtering, then the angle of incidence of the filter can be reduced, but the optical path changing angle becomes too small, making it difficult to accommodate components in a compact space
Solution Approach 1:
The patent employs an asymmetric optical path configuration where the incident light path and the transmitted light path are separated at different angles. The wavelength filter is positioned such that the incident angle is minimized for optimal transmission characteristics, while the optical path changing angle is maximized through asymmetric routing of the light beams, allowing compact component arrangement.
Solution Approach 2:
The patent resolves the contradiction by utilizing spatial dimensionality - specifically by arranging the optical paths in different spatial dimensions. The incident light and transmitted light are separated not only by angle but also by spatial positioning, allowing the system to achieve both a small angle of incidence and a large optical path changing angle through three-dimensional optical path design.
2Volume of moving object
If the optical path changing angle is increased to accommodate components in compact space, then component arrangement becomes easier, but the angle of incidence of the filter increases, degrading transmission characteristics
Solution Approach 1:
The asymmetric optical path design allows the system to independently optimize the angle of incidence for transmission characteristics while maintaining a sufficient optical path changing angle for compact component arrangement. The incident and transmitted paths are asymmetrically configured to decouple these two angular parameters.
Solution Approach 2:
By introducing spatial dimensionality into the optical path design, the patent enables the system to achieve both a large optical path changing angle and a small angle of incidence simultaneously. The light paths are routed in different spatial dimensions, allowing independent optimization of both angular parameters.
3Reliability
If the angle of incidence of the filter is minimized for better angle tolerance and wavelength tolerance, then transmission characteristics improve, but the optical path changing angle becomes too small for compact design
Solution Approach 1:
The asymmetric optical path configuration enables the wavelength filter to operate at a minimal angle of incidence for optimal angle and wavelength tolerance, while the optical path changing angle is simultaneously maximized through asymmetric routing. This decouples the two angular parameters that are typically coupled in conventional symmetric prism designs.
Solution Approach 2:
The patent utilizes spatial dimensionality to resolve the coupling between angle of incidence and optical path changing angle. By routing the optical paths in different spatial dimensions, the system can independently minimize the angle of incidence for tolerance optimization while maintaining a sufficient optical path changing angle for compact design.
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 enables the optical transmitting and receiving apparatuses to accommodate a larger optical path changing angle while minimizing the filter's angle of incidence, enhancing compactness and transmission characteristics, and reducing the etalon effect.
Implementation Method 1
The wavelength filter film is provided on the rear end face, allows to transmit the first laser beam that impinges on the rear end face, reflects the second laser beam impinged from the front end face
Implementation Method 2
The front end face and the rear end face are not parallel to each other so that a prism angle which is an angle at which a surface parallel to the front end face intersects with a surface parallel to the rear end face
Implementation Method 3
reflects the second laser beam impinged from the front end face and thereby multiplexes the first laser beam and the second laser beam
Data Source
AI summary
An optical transmitting apparatus includes semiconductor laser elements. Upon receiving laser beams, a multiplexed beam is emitted from a wavelength multiplexing filter. The wavelength multiplexing filter includes a triangular prism and a wavelength multiplexing filter film. A front end face and a rear end face of the prism are not parallel to each other so that a prism angle at which a surface parallel to the front end face intersects a surface parallel to the rear end face, is an acute angle. The prism angle is the angle at which the laser beam impinging from the front end face into the triangular prism is reflected by the wavelength multiplexing filter film toward the front end face and the multiplexed beam is directed to the optical axis side of the optical fiber.