Interferometer Optical Paths for Temperature-Independent Optical Lockers
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Solution Overview
Problem
Existing optical lockers using Fabry-Perot etalons are temperature-dependent, requiring complex and costly temperature control to maintain calibration, which is not feasible for a temperature-independent solution.
Innovation Solution
Designing interferometers, such as Mach-Zehnder or Michelson interferometers, with two transparent materials of different thermal path length sensitivities, where the optical path difference between intermediate beam paths is made independent of temperature by selecting the lengths of each beam path through these materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If temperature control mechanisms are added to maintain etalon calibration, then measurement precision is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent changes the thermal parameter (temperature sensitivity) of the optical path by introducing materials with different thermal expansion coefficients and refractive index temperature dependencies. The first optical path uses a material with positive thermal expansion coefficient while the second optical path uses a material with negative thermal expansion coefficient, causing their optical path length changes to oppose each other with temperature variation, thereby compensating for temperature effects without active control
Solution Approach 2:
The patent employs composite material strategy by selecting different transparent materials for the two optical paths based on their contrasting thermal properties. Specifically, it uses materials with opposite signs of thermal expansion coefficients and different thermo-optic coefficients to create a passive temperature compensation system where the combined optical path difference remains stable across temperature ranges
2Measurement precision
If temperature control mechanisms are added to maintain etalon calibration, then measurement precision is improved, but manufacturing cost increases
Solution Approach 1:
The patent changes the thermal parameter (temperature sensitivity) of the optical path by introducing materials with different thermal expansion coefficients and refractive index temperature dependencies. The first optical path uses a material with positive thermal expansion coefficient while the second optical path uses a material with negative thermal expansion coefficient, causing their optical path length changes to oppose each other with temperature variation, thereby compensating for temperature effects without active control
Solution Approach 2:
The interferometer performs self-temperature-compensation through its own structure. The two optical paths with opposite thermal responses automatically adjust each other's optical path lengths in response to temperature changes, making the system self-regulating without requiring external temperature control equipment or additional power consumption
3Device complexity
If a single transparent material is used in the etalon, then device complexity is reduced, but temperature independence cannot be achieved
Solution Approach 1:
The patent segments the optical path into two separate paths, each traversing different transparent materials. The first optical path passes through a first transparent material while the second optical path passes through a second transparent material with different thermal properties. This segmentation allows each path to respond differently to temperature changes, enabling compensation when the paths are recombined
Solution Approach 2:
The patent employs composite material strategy by selecting different transparent materials for the two optical paths based on their contrasting thermal properties. Specifically, it uses materials with opposite signs of thermal expansion coefficients and different thermo-optic coefficients to create a passive temperature compensation system where the combined optical path difference remains stable across temperature ranges
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
Achieves a temperature-independent optical locker, reducing manufacturing complexity and cost while maintaining high wavelength measurement resolution and sensitivity over a wide temperature range.
Implementation Method 1
The beam splitter is configured to divide an input beam into first and second intermediate beams, which recombine to form an output beam
Implementation Method 2
at least two transparent materials having different thermal path length sensitivities... A length of each intermediate beam path which passes through each transparent material is selected such that an optical path difference between the first and second intermediate beam path is substantially independent of temperature
Implementation Method 3
the optical path difference between the first and second intermediate beam path is substantially independent of temperature
Data Source
AI summary
There is described an interferometer for use in an optical locker. The interferometer comprises at least two transparent materials having different thermal path length sensitivities. The interferometer is configured such that an input beam is split by the interferometer into first and second intermediate beams, which recombine to form an output beam, the first and second intermediate beams travelling along respective first and second intermediate beam paths which do not overlap. At least one of the intermediate beam paths passes through at least two of the transparent materials. A length of each intermediate beam path which passes through each transparent material is selected such that an optical path difference between the first and second intermediate beam path is substantially independent of temperature.