Monolithic Optical Element for Fiber Collimation
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Solution Overview
Problem
Existing optical systems for collimating or focusing laser light from optical fibers face challenges such as high energy density in the air gap between the fiber tip and imaging optics, requiring precise mechanical alignment and sealing/purging, which complicates safety and environmental considerations, especially with high-power laser applications like Raman probes.
Innovation Solution
A monolithic optical element with opposing surfaces is used to directly contact the optical fiber, eliminating the air gap and high energy density by confining light within the element, allowing for precise collimation or focusing without the need for additional components or alignment complexity, utilizing either a barrel lens or gradient index lens designs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a traditional imaging lens is used to collimate light from the fiber tip, then the light can be collimated, but high energy density light remains in the air gap between the fiber tip and lens, requiring sealing and purging
Solution Approach 1:
The patent introduces an optical coupling element (OCE) as an intermediary component between the fiber tip and the imaging lens. This OCE serves as a mediator that transfers light from the fiber to the lens while eliminating the harmful air gap, thereby resolving the contradiction between achieving light collimation and eliminating the need for sealing/purging arrangements.
Solution Approach 2:
The invention extracts the air gap from the optical path by placing the fiber tip in direct contact with the OCE. This removes the harmful medium (air) containing high energy density light, eliminating the need for sealing and purging while maintaining the collimation function.
2Ease of operation
If the fiber tip is spaced apart from the lens surface, then alignment can be adjusted, but precise mechanical locating is required and high energy density light is present in the air gap
Solution Approach 1:
The optical coupling element acts as a mediator that enables direct contact between the fiber tip and the imaging lens. This intermediary component simplifies the alignment process by eliminating the need for precise mechanical locating while preventing the formation of high energy density light in an air gap.
Solution Approach 2:
The invention merges the fiber tip and lens into a single integrated assembly through direct contact via the OCE. This combination eliminates the air gap and simplifies alignment requirements, as the fiber and lens are positioned relative to each other through the coupling element rather than requiring separate mechanical locating.
3Reliability
If a monolithic optical element is used to directly contact the fiber, then the air gap and high energy density are eliminated, but the element must be precisely designed to minimize mechanical stress
Solution Approach 1:
The patent applies local quality by designing the optical coupling element with specific surface characteristics at the fiber contact interface. The first surface is designed with a curvature radius that minimizes mechanical stress concentration, while maintaining the overall monolithic structure that eliminates air gaps and high energy density light.
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 simplifies the alignment and assembly process, reduces the need for sealing and purging, and minimizes mechanical stress, while ensuring safe and effective light transmission by eliminating hot spots and reducing beam divergence, thus enhancing the reliability and safety of optical measurement probes.
Implementation Method 1
The optical element may provide a collimation function by receiving light from the tip of the fiber and transmitting the light as a collimated beam from the second surface, or the element may provide a focusing function by focusing a collimated beam incident on the second surface to the tip of the fiber
Implementation Method 2
With a GRIN lens, a spatial refractive index gradient performs the light bending instead of a curved air/glass interface
Data Source
AI summary
A monolithic optical element and system is used for collimating or focusing laser light from or to optical fibers. The optical fiber terminates in a tip that directly abuts against the first surface of the optical element. The optical element may provide a collimation or focusing function depending upon whether the abutting fiber delivers light for collimation or receives focused light from a collimated beam. The optical element may be a standard or modified barrel or drum lens, with the first and second surfaces being convex curved surfaces having the same or different radii of curvature. The end of the optical element to which the fiber abuts may have a diameter to match the inner diameter of a ferrule for positioning the fiber. A pair of the elements may be used for collimation and focusing in a Raman probehead or other optical detection system.