Magnetic Sensor Element Lightwave Circuit Alignment
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Solution Overview
Problem
Magnetic field sensors using polarization-plane maintaining optical fibers face challenges in manufacturing due to the need for precise alignment of optical axes, leading to increased light loss and reduced performance, especially when phase differences occur due to Faraday rotation.
Innovation Solution
A magnetic sensor element comprising a planar lightwave circuit with a light branching part, a metal magnetic body type light transmitting film, and a reflecting film, where the input and output optical fibers are aligned and connected to maintain polarization plane integrity, eliminating the need for a wave plate and reducing light loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a reflecting plate and quarter wave plate are used to align optical axes, then the magnetic field sensor can maintain polarization plane, but the manufacturing complexity increases and light loss increases
Solution Approach 1:
The patent removes the reflecting plate and quarter wave plate from the optical path, extracting the problematic alignment components while maintaining the core Faraday rotation sensing function through the polarization-plane maintaining optical fiber alone
Solution Approach 2:
The polarization-plane maintaining optical fiber is designed to perform multiple functions: it maintains polarization plane, enables Faraday rotation sensing, and eliminates the need for separate alignment components like reflecting plates and quarter wave plates
2Measurement precision
If multiple polarization-plane maintaining optical fibers are used, then the sensor can accurately detect magnetic field, but the device becomes difficult to handle
Solution Approach 1:
The patent segments the optical path into a single polarization-plane maintaining optical fiber that performs multiple functions, rather than using multiple separate fibers for different functions, thereby simplifying device handling while maintaining measurement precision
3Loss of energy
If optical axes of multiple components are aligned, then light loss is reduced, but the manufacturing precision requirement increases
Solution Approach 1:
The polarization-plane maintaining optical fiber is designed to self-align and maintain polarization plane without requiring external alignment components like reflecting plates or quarter wave plates, thereby reducing light loss while eliminating complex alignment requirements
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 enables easy manufacturing and minimizes light loss, allowing for precise propagation of phase modulation caused by Faraday rotation, while maintaining uniform light intensities and reducing the complexity of alignment requirements.
Implementation Method 1
detect a magnetic field change by Faraday rotation
Implementation Method 2
a metal magnetic body type light transmitting film that is provided on one end surface of the planar lightwave circuit and transmits light entered from the input optical fiber
Implementation Method 3
a reflecting film that is provided on the metal magnetic body type light transmitting film and reflects the transmitted light
Implementation Method 4
the output optical fiber is a polarization-plane maintaining optical fiber
Data Source
AI summary
To provide a magnetic sensor element and a magnetic sensor device that can be easily manufactured and can reduce a loss of light to the extent possible. The above-described problem is solved by a magnetic sensor element comprising a planar lightwave circuit (11) provided with a light branching part (12), an input optical fiber (19) and an output optical fiber (20) connected to the planar lightwave circuit (11), a metal magnetic body type light transmitting film (30) that is provided on one end surface of the planar lightwave circuit (11) and transmits light entered from the input optical fiber (19), and a reflecting film (40) that is provided on the metal magnetic body type light transmitting film (30) and reflects the transmitted light. The output optical fiber (20) is a polarization-plane maintaining optical fiber, and the input optical fiber (19) and the output optical fiber (20) are aligned and connected to the planar lightwave circuit (11).