Wavelength Selecting Switch Optical Unit with External Adjustment
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Solution Overview
Problem
Conventional wavelength selecting switches face challenges in maintaining optical path precision due to air pressure fluctuations, risk of mirror array displacement, damage to movable optical elements, and trade-offs between optical bench thickness and casing thinning, as well as issues with noise light generation affecting transmission band characteristics.
Innovation Solution
A wavelength selecting switch design with a light path compensating portion that allows adjustment from the outer casing, using a Littman-Metcalf configuration with a transmission type diffraction grating and reflecting elements to prevent noise light overlap, and a deflecting portion with independent wavelength deflection, ensuring stable operation and reduced noise impact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the optical system is sealed within the casing to maintain stability, then air pressure fluctuations are avoided, but adjustment of the optical path becomes difficult after manufacturing
Solution Approach 1:
The device is divided into two separate units: a sealed optical unit containing the optical system and a separate adjustable unit. This segmentation allows the optical path to be adjusted after sealing without compromising the sealed environment, resolving the contradiction between stability and adjustability.
Solution Approach 2:
A transparent window or opening serves as an intermediary between the sealed optical unit and the external adjustment mechanism. This allows optical path adjustment from the outside while maintaining the sealed structure of the optical unit, preserving both stability and ease of operation.
2Stability of the object's composition
If the mirror array is bonded and fixed to the casing, then the structure is stable, but position displacement occurs during coagulation time
Solution Approach 1:
The mirror array is pre-adjusted and fixed in a precise position before final assembly. This preliminary positioning action ensures that even during the coagulation time of bonding, the mirror array maintains its correct position, preventing displacement and ensuring manufacturing precision.
Solution Approach 2:
A positioning mechanism or alignment feature is provided to compensate for potential displacement during bonding. This beforehand cushioning ensures that even if minor position changes occur during coagulation, the final position remains within acceptable tolerances.
3Strength
If the optical bench is made thick to support optical elements, then structural strength is improved, but the casing cannot be thinned
Solution Approach 1:
The optical bench is segmented into multiple layers or modular components. This allows the optical elements to be supported on a thicker internal structure while the external casing can be made thin, resolving the contradiction between strength and thinning.
Solution Approach 2:
The optical bench structure is nested within the casing, with the optical elements mounted on an internal support framework. This nested arrangement allows the optical bench to have sufficient thickness for strength while the casing itself can be thinned, as the internal structure provides the necessary support.
4Measurement precision
If a Littman-Metcalf configuration is used to achieve great dispersion, then the dispersing effect is improved, but noise light is generated affecting transmission band characteristics
Solution Approach 1:
The noise light generated by the Littman-Metcalf configuration is redirected or filtered to serve a useful function, such as being directed away from the transmission path or used for alignment purposes. This converts the harmful noise light into a beneficial element, maintaining high dispersion precision while eliminating harmful effects.
Solution Approach 2:
An optical filter or beam block serves as an intermediary to separate the useful dispersed light from the noise light. This allows the Littman-Metcalf configuration to maintain its great dispersing effect while the noise light is blocked or filtered out, preventing it from affecting transmission band characteristics.
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 precise adjustment of the optical system within the casing, maintains optical path stability, and prevents transmission band deterioration by controlling noise light, thus enhancing the switch's performance and reliability.
Implementation Method 1
a dispersing portion (112) which disperses a wavelength of input light input from the input port (110a)
Implementation Method 2
the light flux is converted into parallel light by a lens (1121)
Implementation Method 3
temporarily bringing the light dispersed by the diffraction grating to the mirror so as to be reflected
Data Source
AI summary
An optical unit for a wavelength-selecting switch according to the present invention comprises: an input port; a dispersion section that produces wavelength dispersion of input light that is input from the input port; a light-collecting element that collects the light dispersed by the dispersion section; an output port; an optical path correction section that shifts the light that is dispersed by the dispersion section; an adjustment section that changes the amount of shift produced by the optical path correction section; and a casing that hermetically seals the input port, dispersion section, light-collecting element, output port, and optical path correction section. The casing has an optically transparent section in a location onto which the light that is collected by the light-collecting element is directed. The adjustment section is arranged outside the casing. The optical path correction section can be controlled from outside the casing by the adjustment section.