Heterodyne Fiber-Optic Interferometer Dynamic Range Extension
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Solution Overview
Problem
The dynamic range of heterodyne fiber-optic interferometers is insufficient for certain applications, leading to limited deployment of large-scale fiber-optic interferometric sensor systems despite their potential benefits.
Innovation Solution
The method involves using an instantaneous carrier frequency to detect demodulator excessions and determine a correction factor, which is then introduced to the demodulator to negate errors and extend the dynamic range of heterodyne fiber-optic interferometers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional demodulation is used in heterodyne fiber-optic interferometers, then the system operates with standard dynamic range, but the dynamic range is insufficient for certain applications
Solution Approach 1:
The patent applies preliminary action by measuring the instantaneous carrier frequency before demodulation and using it to predict and correct demodulator excessions in advance. The system calculates the instantaneous frequency from the I and Q signals, determines potential excession events, and applies correction factors before the demodulated output is finalized, thereby preventing errors rather than correcting them after occurrence
Solution Approach 2:
The patent implements feedback by using the measured instantaneous carrier frequency to generate correction factors that are fed back to correct the demodulated output. The system continuously monitors the carrier frequency, compares it against threshold values to detect excession events, and applies real-time corrections to the phase measurements, creating a closed-loop system that improves measurement accuracy
2Measurement precision
If the dynamic range is extended via instantaneous carrier measurement, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent applies universality by using the instantaneous carrier frequency measurement for multiple purposes: it detects demodulator excessions, determines correction factors, and validates demodulated outputs. The same frequency measurement mechanism serves both as a diagnostic tool for detecting errors and as a basis for generating corrections, reducing the need for separate complexity-intensive systems
Solution Approach 2:
The patent introduces an intermediary element - the instantaneous carrier frequency measurement - that mediates between the raw I/Q signals and the final demodulated output. This intermediary provides critical information about the carrier phase and frequency that enables error detection and correction without requiring direct modification of the demodulator hardware, thereby managing complexity through software-based processing
Data Source
AI summary
A method of dynamic range extension for heterodyne fiber-optic Interferometers, and more particularly towards the use of instantaneous carrier to extend the dynamic range of heterodyne fiber-optic interferometers. The method includes the providing of a heterodyne fiber-optic interferometer having a demodulator and an associated carrier frequency. The method also includes the determining of demodulator excessions. The detecting of the demodulator excessions and the determining of an appropriate correction factor is based on information from the instantaneous carrier frequency. The method also includes the introduction of the appropriate correction factor to the demodulator.