Broadband Fiber Light Source Wavelength Stability Under Radiation
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Solution Overview
Problem
Rare-earth-doped-fiber light sources (FLS) face challenges in maintaining wavelength stability under radiation environments, leading to degraded performance in interferometric fiber optic gyroscopes due to increased radiation-induced losses and reduced optical power.
Innovation Solution
The integration of an undoped fiber with the same host material and cross-sectional structure as the rare-earth doped fiber, placed in proximity to maintain radiation sensitivity, along with an optical configuration where the pump power passes twice through a coupler, allows for effective control of mean wavelength stability through pump power adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the bandwidth of the fiber light source is narrowed to reduce mean wavelength sensitivity to radiation, then wavelength stability is improved, but the bandwidth of the FLS is sacrificed and conversion efficiency is reduced
Solution Approach 1:
The system is divided into two separate fiber paths: one path (through the undoped fiber) that is sensitive to radiation-induced wavelength changes for monitoring purposes, and another path (through the rare-earth-doped fiber) that generates the broadband output. This segmentation allows independent optimization of each path's function.
Solution Approach 2:
The undoped fiber acts as an intermediary element that experiences the same radiation environment and wavelength shifts as the doped fiber, allowing indirect measurement and compensation of radiation effects without directly affecting the broadband generation process in the doped fiber.
2Reliability
If the bandwidth of the fiber light source is narrowed to reduce mean wavelength sensitivity to radiation, then wavelength stability is improved, but conversion efficiency of pump laser power to FLS output power is reduced
Solution Approach 1:
The system separates the monitoring function (undoped fiber) from the energy conversion function (rare-earth-doped fiber), allowing the doped fiber to operate at full bandwidth for maximum conversion efficiency while the undoped fiber monitors wavelength shifts independently.
Solution Approach 2:
The undoped fiber serves as an intermediary sensor that measures radiation-induced wavelength changes without participating in the energy conversion process, thus not affecting the pump laser to output power efficiency of the doped fiber.
3Object-affected harmful factors
If radiation shielding is added to protect the FLS, then protection from radiation is improved, but the device complexity and size increase
Solution Approach 1:
The system uses itself to monitor and compensate for radiation effects. The undoped fiber, experiencing the same radiation environment, provides real-time information about wavelength shifts, enabling the system to self-correct without external shielding or complex protection mechanisms.
Solution Approach 2:
The system implements a feedback mechanism where radiation-induced wavelength changes detected in the undoped fiber path are used to adjust the pump laser parameters, automatically compensating for the effects of radiation without requiring passive shielding.
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
This solution maintains high wavelength stability and optical power output for FLS, even in radiation environments, without sacrificing bandwidth, thereby ensuring stable performance of interferometric fiber optic gyroscopes.
Implementation Method 1
a rare-earth doped fiber used as an active medium for the broadband light source
Implementation Method 2
radiation from high energy particles and/or high frequency radiation increase the loss within the whole gyro optical circuit
Implementation Method 3
a coupler configured to direct a first portion of pump power from a pump laser to the undoped fiber
Implementation Method 4
a wavelength division multiplexer configured to input a second portion of pump power from the pump laser to the rare-earth doped fiber
Data Source
AI summary
A rare-earth-doped-fiber light source with wavelength stability includes a rare-earth doped fiber and an undoped fiber placed in proximity to each other and having the same host material and the same cross-sectional structure, a coupler configured to direct a first portion of pump power from a pump laser to the undoped fiber so the first portion of pump power was twice passed through the coupler; and a wavelength division multiplexer configured to input a second portion of pump power from the pump laser to the rare-earth doped fiber. The rare-earth doped fiber is an active medium for the broadband light source and includes a fiber core doped with rare-earth ions. The undoped fiber includes a rare-earth-dopant-free fiber core. The length of the undoped fiber is one of the same as that of the doped fiber or optimized to match a radiation sensitivity of the doped fiber.