Integrated Optical Gyroscope Without a Circulator for Low-Loss Sensing
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Solution Overview
Problem
Conventional interferometric optical gyroscopes face issues with circulator-induced loss and reflection, which affect performance stability and increase cost, and are difficult to integrate into monolithic chips, while system errors and environmental disturbances further compromise accuracy.
Innovation Solution
An integrated interferometric optical gyroscope design that eliminates the need for a circulator by using polarization splitting rotation modules and a helical waveguide to transmit light in opposite directions, allowing for fixed phase differences and optimal working points, thereby improving performance and reducing losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a circulator is used to extract returned light, then light direction control is achieved, but optical loss increases and cost increases
Solution Approach 1:
The patent removes the circulator component from the optical gyroscope system. By using a 50/50 coupler instead, the system extracts returned light without the need for the circulator, thereby reducing optical loss (eliminating the 1-2 dB loss from the circulator) and simplifying device complexity while maintaining the ability to direct light to the detector
Solution Approach 2:
The patent uses a 50/50 coupler to create a functional copy of the circulator's light direction control capability. The coupler splits and combines light paths to achieve similar functionality (directing returned light to the detector) without requiring the magneto-optical circulator component, thus reducing loss and complexity
2Loss of energy
If a 50/50 coupler is used to extract returned light, then light direction control is achieved, but additional link losses occur
Solution Approach 1:
The patent combines the functions of the circulator and the 50/50 coupler into a single integrated approach. By using the 50/50 coupler for both light splitting and returned light extraction, the system eliminates the need for separate circulator and coupler components, reducing total optical loss while maintaining operational simplicity through functional integration
3Ease of manufacture
If a circulator is used, then reflected light is controlled, but manufacturing complexity increases
Solution Approach 1:
The patent extracts the circulator component from the system and replaces it with standard 50/50 coupler components. This removal simplifies manufacturing by eliminating the need for magneto-optical materials and complex circulator fabrication, while the coupler-based solution uses more readily available components that are easier to manufacture and integrate
4Reliability
If reflected light returns to the light source, then light path simplicity is maintained, but light source performance is affected
Solution Approach 1:
The patent introduces the 50/50 coupler as an intermediary component between the light source and the optical path. This coupler mediates the light paths by splitting the outgoing light and combining the returned light, preventing direct reflection to the light source while maintaining system reliability. The coupler acts as a buffer that protects the light source from destabilizing reflections
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 proposed design achieves low link optical loss, enhances performance stability by eliminating reflected light to the source, and simplifies manufacturing, while effectively calculating rotation speed information.
Implementation Method 1
the two polarization splitting rotation modules are coupled to a telecentric end and a pericentric end of the helical waveguide module respectively, and configured for converting the two beams of light waves in a same TE polarization state into a transverse electric (TE) polarization state and a transverse magnetic (TM) polarization state
Implementation Method 2
As the gyroscope rotates perpendicularly to a plane, two paths of light propagating in opposite directions result in different phase shifts which are proportional to a rotation speed
Implementation Method 3
The phase shift is converted to intensity information when returned light is further interfered by the 50/50 coupler
Implementation Method 4
The light is detected by a photoelectric detector after passing through a circulator
Data Source
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AI summary
Provided are an integrated interferometric optical gyroscope, assembly, system, and a method for calculating rotation speed information. The gyroscope includes a light source module, a first coupling module, a second coupling module, at least two polarization splitting rotation modules, a photoelectric detection module and a helical waveguide module, wherein the two polarization splitting rotation modules are coupled to a telecentric end and a pericentric end of the helical waveguide module respectively, and are configured for converting the two beams of light waves in a same TE polarization state into a TE polarization state and a TM polarization state, sending the light waves to the two ends of the helical waveguide module to enable the light waves to be transmitted in opposite directions in the helical waveguide module respectively, then receiving the two beams of light passing through the helical waveguide module and converting the polarization states of the two paths of light back to the same TE polarization state. Due to the gyroscope having a circulator or a 50/50 coupler omitted, light waves are prevented from being reflected to the light source, and the influence of system errors, drifting or disturbance, environment temperature changes and the like on the performance stability of the gyroscope can be eliminated.