Broadband Resonator Optical Gyroscope RIN Subtraction by Spectral Filtering
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Resonator fiber optic gyroscopes using broadband light sources face significant challenges with relative intensity noise due to mismatched optical spectra at different points in the optical path, rendering current noise subtraction techniques ineffective.
Innovation Solution
Implementing an optical filter to reshape the optical spectrum of phase-modulated signals to match that of the resonator, combined with a relative intensity noise detector and photodetector, to accurately subtract noise and improve rotation rate detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a broadband light source is used in a resonator fiber optic gyroscope, then the device can operate with simpler configuration and reduced fiber length, but relative intensity noise increases significantly due to spectrum mismatch at different points in the optical path
Solution Approach 1:
The patent changes the spectral parameters of the light by introducing an optical filter that reshapes the broadband spectrum to match the resonator's spectral characteristics. This parameter transformation allows the use of broadband light sources while maintaining measurement precision by eliminating spectrum mismatch-induced noise.
Solution Approach 2:
The optical filter acts as an intermediary element between the broadband light source and the resonator. It mediates the spectral incompatibility by transforming the broadband spectrum into a shape that matches the resonator's spectral response, thereby enabling effective operation without direct spectrum matching.
2Object-affected harmful factors
If current noise subtraction techniques are applied to broadband light sources, then noise reduction might be achieved, but the techniques are ineffective due to mismatched optical spectra at different points in the optical path
Solution Approach 1:
The optical filter is positioned to pre-shape the spectrum of the light before it enters the resonator and before detection occurs. This preliminary spectral transformation ensures that the light spectrum is matched to the resonator characteristics in advance, making subsequent noise subtraction techniques effective where they would otherwise fail.
3Measurement precision
If the optical spectrum is reshaped using an optical filter, then relative intensity noise is reduced, but device complexity increases due to additional optical components
Solution Approach 1:
The patent extracts only the necessary spectral components by using an optical filter to reshape the broadband spectrum. Rather than requiring complex noise cancellation systems, it extracts and retains only the spectral portions that match the resonator characteristics, simplifying the overall approach while maintaining precision.
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 described techniques significantly reduce relative intensity noise, enhancing the accuracy of rotation rate measurements in resonator optical gyroscopes using broadband light sources.
Implementation Method 1
an optical filter configured to filter a first portion of the phase-modulated optical signals to generate filtered, phase-modulated optical signals
Implementation Method 2
a phase modulator configured to apply a phase modulation to optical signals that have been coupled out of the optical resonator by the second optical coupler to generate phase-modulated optical signals
Implementation Method 3
a second photodetector configured to convert the phase-modulated optical signals to second electrical signals indicative of a power level of the phase-modulated optical signals after passing through the optical resonator in the second direction
Implementation Method 4
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
Data Source
AI summary
A method of operating a resonator optical gyroscope includes generating optical signals having broadband frequency range; coupling optical signals into optical resonator (OR) to propagate in first direction and out of OR after optical signals pass through OR in first direction; applying phase modulation to optical signals coupled out of OR to generate phase-modulated optical signals; filtering first portion of phase-modulated optical signals to generate filtered, phase-modulated optical signals; generating first electrical signals indicative of power level of the filtered, phase-modulated optical signals and RIN; coupling second portion of phase-modulated optical signals into OR to propagate in second direction and out of OR after phase-modulated optical signals pass through the OR in second direction; generating second electrical signals indicative of power level of phase-modulated optical signals after passing through OR in second direction; and determining a rotation rate based on the first electrical signals and the second electrical signals.