Broadband Resonator Optical Gyroscope with Distributed Gain
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Solution Overview
Problem
Resonator fiber optic gyroscopes using narrow linewidth lasers face power losses due to the optical Kerr effect and reduced output intensity when employing broadband light sources, which is problematic for high-precision applications, especially in integrated photonics-based gyroscopes.
Innovation Solution
Implementing gain elements at various positions on the optical path to amplify optical signals that have passed through the optical resonator in one or both directions, combined with phase modulation and polarizers to filter out undesirable polarization states, thereby enhancing detectable optical power without increasing total power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If broadband light sources are used in resonator fiber optic gyroscopes, then power losses due to the optical Kerr effect are reduced, but output intensity decreases
Solution Approach 1:
The optical path is segmented into multiple passes through the resonator, with gain elements strategically placed at specific positions to amplify signals between passes. This segmentation allows the system to accumulate optical power from multiple resonator passes while managing the trade-off between broadband operation and output intensity through distributed amplification stages.
Solution Approach 2:
The system changes the operational parameters by implementing phase modulation on the broadband light source and using polarizers to control polarization states. These parameter changes enable efficient coupling into the resonator and extraction of amplified signals while maintaining broadband operation and reducing Kerr effect losses.
2Illumination intensity
If gain elements are added to amplify optical signals, then detectable optical power increases, but device complexity increases
Solution Approach 1:
Polarizers are introduced as intermediary elements to manage polarization states of the broadband light before it enters the resonator and after it passes through. These polarizers act as mediators that enable efficient coupling and extraction while working synergistically with the gain elements to achieve high detectable power without requiring complex polarization control mechanisms.
Solution Approach 2:
Phase modulation is applied periodically to the broadband light source, creating phase-modulated signals that resonate with the resonator modes. This periodic action enhances the interaction between light and resonator, improving coupling efficiency and signal extraction while working with the gain elements to amplify the modulated signals at detectable levels.
3Productivity
If multiple optical couplers are used to manage signal direction, then signal routing efficiency improves, but device complexity increases
Solution Approach 1:
The optical couplers are configured with asymmetric coupling ratios optimized for specific functions: the first coupler is optimized for coupling broadband light into the resonator, while the second coupler is optimized for extracting amplified signals. This asymmetric design improves signal routing efficiency by matching each coupler's characteristics to its specific role in the optical path, reducing the need for additional coupling stages.
Solution Approach 2:
The first optical coupler performs preliminary coupling of the broadband light source signal into the resonator before the light undergoes multiple passes and amplification. This preliminary action prepares the signal for subsequent amplification by gain elements and final extraction by the second coupler, optimizing the overall signal routing efficiency while maintaining a manageable device architecture.
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 solution significantly improves optical power levels at the detector, enabling accurate rotation rate measurements by maintaining or reducing power consumption, thus addressing the power loss issues associated with broadband light sources in resonator fiber optic gyroscopes.
Implementation Method 1
The resonance frequencies of the optical resonator are frequency-shifted due to the Sagnac effect when the RFOG experiences a rotation about its sense axis.
Implementation Method 2
a gain element configured to amplify optical signals that have been coupled out of the optical resonator and passed through the optical resonator in the first direction to generate amplified optical signals
Implementation Method 3
a photodetector configured to convert the amplified optical signals from to corresponding electrical signals based on a power level of the amplified optical signals
Data Source
AI summary
A method of operating a resonator optical gyroscope includes generating optical signals having a broadband frequency range. The method includes coupling the optical signals into an optical resonator (OR) to propagate in a first direction and coupling the optical signals out of the OR after the optical signals pass through the OR in the first direction. The method includes coupling optical signals into the OR to propagate in a second direction and coupling optical signals out of the OR after the optical signals pass through the OR in the second direction. The method includes amplifying the optical signals coupled out of the OR by the second optical coupler or the optical signals coupled out of the OR by the first optical coupler to generate amplified optical signals and generating electrical signals corresponding to the amplified optical signals. The method includes determining a rotation rate based on the electrical signals.