Wavelength Selective Switch Thermal Expansion Compensation
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Solution Overview
Problem
Wavelength selective switches (WSS) face degradation in pass band characteristics due to temperature changes, primarily caused by the temperature characteristics of the diffraction grating and other components, leading to decreased performance and increased power consumption from constant temperature control mechanisms.
Innovation Solution
A wavelength selective switch design where the collective lens is fixed at one end, allowing it to expand with heat in a direction opposite to the beam deviation, with a temperature monitor and mirror drive control system to adjust mirror angles and correct beam positions, eliminating the need for constant temperature control mechanisms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If constant temperature control mechanisms are used to maintain pass band characteristics, then temperature stability is improved, but power consumption increases
Solution Approach 1:
The collective lens is designed to utilize its own thermal expansion to compensate for beam position deviation. When temperature changes cause the diffraction grating to deviate beam angles, the collective lens expands or contracts in a way that automatically realigns the beams with the mirrors, eliminating the need for external temperature control mechanisms and reducing power consumption.
Solution Approach 2:
The invention exploits thermal expansion of the collective lens to counteract temperature-induced beam deviation. The lens material is selected and designed such that its thermal expansion coefficient creates an opposing effect to the diffraction grating's temperature characteristics, automatically compensating for wavelength positioning errors without requiring active cooling or heating systems.
2Stability of the object's composition
If the collective lens is fixed at both ends to maintain structural stability, then structural stability is improved, but pass band characteristics degrade due to beam position deviation
Solution Approach 1:
The collective lens is fixed at only one end rather than both ends, allowing localized freedom of movement in the direction of angular dispersion. This partial fixation provides structural stability while enabling the lens to expand or contract locally to compensate for beam position deviations caused by temperature changes, thereby maintaining pass band characteristics.
Solution Approach 2:
The system transitions from a completely fixed collective lens to a dynamically adjustable configuration where the lens can move freely in the angular dispersion direction. This dynamic capability allows the lens to adapt to temperature-induced changes in beam angles, maintaining optimal optical alignment and pass band characteristics without requiring rigid fixation at both ends.
3Manufacturing precision
If the diffraction grating is made with high precision to maintain pass band, then manufacturing precision is improved, but temperature sensitivity increases causing greater beam deviation
Solution Approach 1:
The invention changes the physical parameters of the system by selecting a collective lens material with specific thermal expansion characteristics. This parameter change allows the lens to compensate for the temperature sensitivity of the diffraction grating, offsetting beam deviation caused by temperature changes while maintaining the high manufacturing precision of the grating itself.
Solution Approach 2:
The invention converts the harmful effect of thermal expansion into a beneficial compensation mechanism. The thermal expansion of the collective lens, which would normally be considered a detrimental factor, is harnessed to counteract the beam deviation caused by temperature changes in the diffraction grating, turning a potential harm into a useful compensating effect.
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
Effectively suppresses pass band degradation due to temperature changes, maintaining high precision and reliability in optical switching without the need for additional power-consuming control systems.
Implementation Method 1
a spectroscopic element for separating input light and providing angular dispersion depending on the wavelengths
Implementation Method 2
a collective lens for gathering light output from the spectroscopic element
Implementation Method 3
a movable reflection block that includes a plurality of mirrors arranged in the direction of angular dispersion made by the spectroscopic element, changes the angles of the mirrors to a direction differing from the direction of angular dispersion, and reflects light from the collective lens
Implementation Method 4
As the spectroscopic element 51, a diffraction grating is generally used. The diffraction grating is an optical element having a number of parallel grooves made at regular spacing on a glass substrate and performs wavelength separation by optical diffraction by giving a plurality of wavelength components input at a certain angle output angles depending on the wavelengths.
Data Source
AI summary
A wavelength selective switch for suppressing degradation of pass band characteristics when the temperature rises. The wavelength selective switch includes a spectroscopic element for separating input light and providing angular dispersion depending on wavelengths, a collective lens for gathering light output from the spectroscopic element, and a movable reflection block which includes a plurality of mirrors arranged in the direction of angular dispersion made by the spectroscopic element, changes the angles of the mirrors in a direction differing from the direction of angular dispersion, and reflects the light coming from the collective lens. The collective lens is fixed at one end with respect to the direction of angular dispersion, expands with heat in a direction in which it is not fixed when the temperature rises, and outputs the light in a direction opposite to the direction in which the angle of light output from the spectroscopic element changes.