Ring Laser Gyroscope Readout Mirror Assembly for Scatter Reduction
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Solution Overview
Problem
Ring laser gyroscopes face challenges in achieving high-grade, low-noise performance due to external laser beam scatter sources, particularly from defects in the beam splitter coating on the backside wedge mirror surface, which are difficult and costly to polish.
Innovation Solution
A method involving a super polish on a flat surface of an optical part, application of a high-quality beam splitter coating, and bonding with a refractive index matching optical adhesive to a coarse polished wedge angle surface to minimize scattering, using an optical substrate component with a parallel and angled surface structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a high-grade polish is applied to the backside wedge mirror surface to reduce laser beam scattering, then the noise performance is improved, but the manufacturing complexity and cost increase significantly
Solution Approach 1:
The mirror assembly is segmented into two separate components: a wedge-shaped substrate component and a flat optical part. The substrate component only requires coarse polishing on its angled surface, while the separate optical part receives the super polish treatment. This segmentation allows each component to be optimized independently, reducing the overall manufacturing complexity while maintaining low scattering performance.
Solution Approach 2:
A refractive index matching optical adhesive is introduced as an intermediary between the coarse polished substrate component and the super polished optical part. This adhesive layer optically couples the two components while compensating for surface imperfections, allowing the system to achieve low scattering without requiring the expensive and complex super polish on the wedge-shaped substrate itself.
2Manufacturing precision
If a super polish is applied to the wedge angle surface to reduce external scatter sources, then the beam quality is improved, but the manufacturing time and cost increase
Solution Approach 1:
The manufacturing process is segmented so that the time-consuming super polish operation is applied only to the flat optical part, not to the wedge-shaped substrate component. The substrate component undergoes a faster coarse polishing process, while the optical part receives the thorough super polish treatment. This segmentation significantly reduces total manufacturing time while maintaining beam quality.
Solution Approach 2:
The refractive index matching optical adhesive acts as a mediator that allows the coarse polished surface to function effectively in conjunction with the super polished optical part. This intermediary enables the system to achieve high beam quality without requiring the wedge angle surface to undergo the time-consuming super polish process.
3Object-affected harmful factors
If defects in the beam splitter coating on the backside wedge mirror surface are eliminated through high-grade polishing, then external laser beam scatter is reduced, but the manufacturing cost increases
Solution Approach 1:
The system is segmented into a substrate component housing the beam splitter coating and a separate optical part that receives the super polish treatment. By separating these functions, the expensive super polish is applied only to the optical part, not to the substrate component containing the beam splitter coating. This reduces manufacturing cost while still eliminating scatter sources that affect beam quality.
Solution Approach 2:
The refractive index matching optical adhesive serves as an intermediary that optically couples the beam splitter coating on the substrate with the super polished optical part. This intermediary layer helps eliminate scatter at the interface between components, reducing external laser beam scatter without requiring expensive polishing of the beam splitter coating itself.
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 method effectively reduces external cavity laser light scattering, enhancing the performance capability of ring laser gyroscopes by mitigating unintended beam scattering, thus improving noise reduction and operational efficiency.
Implementation Method 1
bonding the beam splitter side of the optical part, using an optical adhesive, to the coarse polished second upper surface portion of the optical substrate component... wherein a refractive index of the optical adhesive when cured matches a refractive index of the optical part
Data Source
AI summary
A method of making a readout mirror for a ring laser gyroscope comprises forming an optical substrate component that includes a lower surface, a first upper surface portion substantially parallel to the lower surface, and a second upper surface portion angled with respect to the lower surface; performing a coarse polish of the second upper surface portion; forming an optical part having a first surface; performing a super polish of the first surface of the optical part; applying a first beam splitter layer to the super polished first surface of the optical part, to produce a beam splitter side of the optical part; and bonding the beam splitter side of the optical part, using an optical adhesive, to the coarse polished second upper surface portion of the substrate component, to produce a reflector member. The reflector member is configured to reduce external cavity light scattering in the ring laser gyroscope.