Optical Isolator Layout for Back-Propagation Blocking
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Solution Overview
Problem
Optical systems face challenges in achieving unidirectional propagation of optical beams and signals, particularly in applications like fiber-optic gyroscopes, where back-propagation of optical beams can be detrimental to the beam source.
Innovation Solution
An optical isolator system utilizing an alternating sequence of birefringent crystals and Faraday rotators, combined with phase adjusters, transversely shifts and phase-aligns orthogonally polarized components to allow propagation in one direction while blocking it in the opposite direction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If optical beams are provided along the same optical path in a collinear manner, then optical systems can be simplified and space-efficient, but back-propagation of optical beams occurs which is detrimental to the source
Solution Approach 1:
The optical isolator element segments the optical beam into two orthogonally linearly polarized components (first and second components) that propagate through different paths within the isolator. The first component transmits through the first birefringent crystal while the second component is blocked, and vice versa for the opposite direction, achieving unidirectional propagation without requiring separate external paths
Solution Approach 2:
The patent introduces an optical isolator element as an intermediary device between the optical source and the optical path. This isolator element uses birefringent crystals and Faraday rotators to mediate the polarization states of the optical beam, enabling unidirectional propagation by blocking the back-propagating beam while allowing the forward beam to pass through
2Reliability
If optical isolators are implemented to provide unidirectional propagation, then back-propagation is prohibited, but device complexity increases due to multiple birefringent crystals and Faraday rotators
Solution Approach 1:
The patent merges multiple optical functions (polarization splitting, phase adjustment, and isolation) into a single integrated optical isolator element. The first and second birefringent crystals are coupled together with Faraday rotators in between, creating a compact structure where the first component and second component are simultaneously separated and phase-adjusted without requiring separate external devices
Solution Approach 2:
The patent utilizes parameter changes in the polarization state of the optical beam to achieve unidirectional propagation. By changing the polarization orientation through Faraday rotators and adjusting the phase difference between the first and second components through the birefringent crystals, the system dynamically controls which component transmits and which is blocked, achieving isolation without complex mechanical structures
3Manufacturing precision
If phase adjusters are added to align the first and second components, then wavefront alignment is achieved, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The patent incorporates phase adjusters that are pre-configured during manufacturing to provide the necessary phase difference between the first and second components. The birefringent crystals are designed with specific thicknesses and orientations that preliminarily establish the required phase relationship, reducing the need for complex post-assembly adjustments and simplifying the manufacturing process 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 system effectively facilitates unidirectional propagation of optical beams, preventing back-propagation and maintaining system performance by using birefringent crystals and Faraday rotators to shift and align polarization components.
Implementation Method 1
The optical isolator element can provide optical isolation based on transverse shifting the first and second components of the optical beams relative to each other
Implementation Method 2
At least one phase adjuster adjusts a relative phase of the first and second components of the first optical beam to align the components of the first optical beam
Implementation Method 3
The optical isolator element includes a first birefringent crystal coupled to the first port, a first Faraday rotator coupled to the first birefringent crystal, a second birefringent crystal coupled to the first Faraday rotator, a second Faraday rotator coupled to the second birefringent crystal, and a third birefringent crystal coupled between the second Faraday rotator and the second port
Implementation Method 4
The optical isolator element includes a first Faraday rotator coupled to the first birefringent crystal, a second Faraday rotator coupled to the second birefringent crystal
Data Source
AI summary
An optical isolator system includes an optical isolator element that transmits a first optical beam provided at a first port to be output from a second port and blocks a second optical beam provided at the second port from being output from the first port. The optical beams each include a first component and a second component that are orthogonally linearly polarized. The optical isolator element can provide optical isolation based on transverse shifting the first and second components of the optical beams relative to each other to provide propagation of the first optical beam from the first port to the second port and to prevent propagation of the second optical beam from the second port to the first port. At least one phase adjuster adjusts a relative phase of the first and second components of the first optical beam to align the components of the first optical beam.