Optical Isolator Assembly to Prevent Polarizer Warping
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Solution Overview
Problem
Conventional optical isolators face challenges in bonding thin polarizers due to film stress-induced warping, leading to peeling issues and increased costs with additional warp suppression films, which cannot fully eliminate warping variations.
Innovation Solution
Bond polarizing glass to the Faraday rotator before forming the anti-reflection film, allowing for almost zero warping and secure attachment, enabling thinner designs with freely adjustable film thickness and structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If anti-reflection film is formed on one surface of the polarizer before bonding, then anti-reflection performance is improved, but the polarizer warps due to film stress making bonding difficult and increasing peeling risk
Solution Approach 1:
The patent applies preliminary action by bonding the polarizer to the Faraday rotator before forming the anti-reflection film. This sequence prevents the anti-reflection film from causing warping during the bonding process, as the film is formed after the polarizer is already securely attached. The bonding is performed when the polarizer surface is still flat, ensuring proper adhesion without the complications of warping.
2Volume of moving object
If polarizer thickness is reduced to miniaturize the optical isolator, then device size is reduced, but film stress-induced warping increases making bonding more difficult
Solution Approach 1:
The patent resolves this contradiction by performing the bonding operation before forming the anti-reflection film. This preliminary bonding action ensures that thin polarizers can be securely attached to the Faraday rotator before any warping occurs due to film stress. The polarizer is bonded in its flat state, and only after bonding is the anti-reflection film formed, preventing warping from compromising the bonding quality.
3Manufacturing precision
If warp suppression film is added to counteract film stress, then polarizer warping is suppressed, but manufacturing cost increases and warping variations cannot be completely eliminated
Solution Approach 1:
The patent applies the inversion principle by reversing the conventional sequence of operations. Instead of forming the anti-reflection film first and then bonding the polarizer (which causes warping), the patent bonds the polarizer first and then forms the anti-reflection film. This reversed sequence eliminates the need for additional warp suppression films while maintaining polarizer flatness and bonding quality.
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
Achieves a thinner optical isolator with minimal warping and secure bonding, ensuring effective anti-reflection performance without additional warp suppression films, reducing peeling risks and cost.
Implementation Method 1
forming an anti-reflection film on one surface of each of the polarizers of the above (1), so that the reflectance for the wavelength band of light being used (for example, a wavelength band of 1250 to 1650 nm for use in optical communications) is equal to or lower than a predetermined value (for example, 0.3% or below)
Implementation Method 2
the Faraday rotator is adjusted to such a thickness that the rotator can rotate the polarization plane of light in a predetermined wavelength by 45°in a saturation magnetic field
Implementation Method 3
producing polarizers (polarizing glasses)
Data Source
AI summary
Provided is a method of producing an optical isolator that is thinner than conventional optical isolators but is extremely less affected by film stress in an anti-reflection film. An optical isolator production method in an embodiment is a method of producing an optical isolator including a Faraday rotator and a polarizing glass attached to the Faraday rotator, and includes the steps of bonding the polarizing glass to the Faraday rotator and forming an anti-reflection film on a surface of the bonded polarizing glass.