Redundant Seismic Sensor Cable With Reversible Optical Connections
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Solution Overview
Problem
Seismic sensing cables are prone to failure due to rough handling and severe environmental conditions, leading to loss of signals from multiple sensors when input or return bus fibers break, resulting in significant or complete signal loss.
Innovation Solution
The implementation of a bi-directional optical sensor cable with redundant source light and signal return paths, allowing for continued signal acquisition even if a source light fiber or signal return fiber fails, using a combination of wavelength division multiplexed (WDM) and frequency division multiplexed (FDM) optical telemetry with auxiliary fibers and modularized optical couplings to ensure continuous operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single source light fiber and signal return fiber are used in the sensor cable, then the device complexity is reduced, but the reliability deteriorates due to complete signal loss when fibers break
Solution Approach 1:
The patent implements redundant source light fibers and signal return fibers as preventive measures before fiber failure occurs. When the primary fiber breaks, the redundant fibers are already in place to immediately take over signal transmission, preventing complete system failure and enabling continued operation with all sensors functional.
Solution Approach 2:
The patent changes the system configuration from single-fiber to multi-fiber architecture, specifically adding auxiliary source light fibers and signal return fibers. This parameter change transforms the system from vulnerable to resilient, allowing signal acquisition from all sensors even when primary fibers fail.
2Reliability
If redundant fibers are added to the sensor cable, then the reliability improves by maintaining signal acquisition during fiber failure, but the device complexity increases
Solution Approach 1:
The auxiliary source light fibers and signal return fibers serve multiple functions: they act as primary transmission paths during normal operation and as backup paths when primary fibers fail. This multi-functionality ensures continuous signal acquisition from all sensors without requiring separate redundant systems, thereby managing complexity while maintaining high reliability.
Solution Approach 2:
The redundant fiber paths are pre-configured and ready before any failure occurs. When fiber breakage happens, the system seamlessly switches to the pre-prepared auxiliary fibers, ensuring uninterrupted signal acquisition and maintaining system reliability without adding operational complexity during critical moments.
3Manufacturing precision
If optical splicing and splitting components are integrated into the cable, then the manufacturing precision is improved, but the reliability worsens due to more failure-prone system elements
Solution Approach 1:
The patent removes optical splicing and splitting components from the cable assembly and places them in separate external equipment. This extraction eliminates potential failure points within the cable, improving reliability by reducing the number of integrated components that could fail, while still achieving precise optical coupling through the external equipment's controlled environment.
Solution Approach 2:
The system is divided into modular segments: the cable contains only passive fiber transmission elements, while active optical coupling components are separated into external equipment. This segmentation isolates potential failure sources, allowing the cable to maintain high reliability while external equipment handles the precision optical coupling functions.
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 redundant path configuration significantly increases the survivability of the seismic sensing cable by allowing signal acquisition from all sensors even in the event of fiber failure, enhancing the reliability and durability of the seismic sensing system.
Implementation Method 1
A selected length of optical fiber ultimately affixed to an optical sensing device carries light from a source, which is distributed to the various optical sensors in a sensing system
Implementation Method 2
Sensors known in the art which respond to the foregoing physical parameters generate an optical signal in response to the detected physical parameter. The optical signal may be, for example, a change in wavelength, a change in phase or an interference pattern
Data Source
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AI summary
An optical sensor cable (10) includes at least one light source fiber (14) extending substantially the entire length of the cable. A plurality of optical sensors (30) are functionally coupled at an input thereof to the at least one light source fiber. At least one signal return fiber extends substantially along the entire length of the cable and is functionally coupled to an output of each of the optical sensors. The at least one source light fiber (14) and the at least one signal return fiber are configured to be coupled at either end thereof to a respective one of a light source and a photodetection device.