Semiconductor Ring Laser Gyro Using Prism-Based Optical Circuit
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Solution Overview
Problem
Conventional semiconductor ring laser gyros are expensive to produce, require advanced coating techniques, and are susceptible to disturbances that can shift the optical axis, leading to inaccurate measurements.
Innovation Solution
A semiconductor ring laser gyro design using inexpensive materials like rectangular and trapezoidal prisms or corner cube prisms for the optical circuit, with internal reflection and a transmissive mirror for beam multiplexing, reducing the need for expensive equipment and minimizing the impact of disturbances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If silicon micromachining technique with anisotropic etching is used to fabricate mirrors, then positioning precision of mirrors is improved, but manufacturing cost increases and device complexity increases
Solution Approach 1:
The patent replaces expensive silicon micromachining with inexpensive right-angle prisms made of ordinary optical glass or plastic. These prisms serve as disposable, easy-to-manufacture components that achieve the same mirror positioning function without requiring costly cleanroom fabrication processes.
Solution Approach 2:
The patent substitutes the mechanical silicon micromachining process with a simpler optical system using right-angle prisms. The prisms utilize total internal reflection instead of metal or dielectric coatings, eliminating the need for complex coating equipment and processes.
2Reliability
If metal coating or dielectric multilayer coating is applied to increase reflectance, then optical performance is improved, but manufacturing complexity and cost increase
Solution Approach 1:
The patent replaces coating processes with total internal reflection in right-angle prisms. This optical phenomenon provides high reflectance without requiring any metal or dielectric coatings, thereby eliminating complex coating equipment and multi-step manufacturing processes.
Solution Approach 2:
The patent uses uncoated or simply coated right-angle prisms that rely on total internal reflection. These inexpensive optical components achieve the required reflectance performance without advanced coating techniques, reducing both material and processing costs.
3Reliability
If dithering is applied to prevent lock-in phenomenon, then measurement reliability is improved, but optical axis stability deteriorates
Solution Approach 1:
The patent introduces right-angle prisms as intermediary optical elements that decouple the dithering motion from the optical axis. The prisms redirect light paths in a way that makes the system less sensitive to small angular deviations caused by dithering, thereby maintaining optical axis stability while still preventing lock-in.
4Ease of operation
If transmissive mirror is used to introduce light to pickup mirrors, then beat light detection is enabled, but light loss increases
Solution Approach 1:
The patent uses right-angle prisms that serve multiple functions: they act as mirrors for the main optical path through total internal reflection, and simultaneously enable beam extraction for beat light detection. This multi-functionality eliminates the need for separate transmissive mirrors, reducing light loss while maintaining detection capability.
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 design allows for cost-effective production and stable measurement precision by eliminating the need for advanced coatings and reducing the influence of disturbances, such as dithering and refractive index fluctuations.
Implementation Method 1
at least one reflection prism comprising a plurality of reflection surfaces for forming an optical circuit, the at least one reflection prism adapted to receive and internally reflect the light emitted from the semiconductor laser
Implementation Method 2
a transmissive mirror disposed at one of the plurality of reflection surfaces of the at least one reflection prism and adapted to transmit part of the light traveling clockwise and part of the light traveling counterclockwise through the optical circuit
Implementation Method 3
a beam multiplexing prism for multiplexing the light transmitted through the transmissive mirror
Implementation Method 4
a gyroscope has been conventionally known as a means of measuring the angular velocity of an object. Among others, a ring laser gyro, which utilizes the Sagnac effect to precisely measure the angular velocity
Data Source
AI summary
A semiconductor ring laser gyro includes: a semiconductor laser for emitting light from each end of the gyro; at least one reflection prism comprising a plurality of reflection surfaces for forming an optical circuit, the at least one reflection prism adapted to receive and internally reflect the light emitted from the semiconductor laser; a transmissive mirror disposed at one of the plurality of reflection surfaces of the at least one reflection prism and adapted to transmit part of the light traveling clockwise and part of the light traveling counterclockwise through the optical circuit; and a beam multiplexing prism for multiplexing the light transmitted through the transmissive mirror.