Structured Surface Optical Ferrule for Low Reflectance
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Solution Overview
Problem
Optical connectors face challenges in minimizing polarization-dependent optical reflectance and transmittance, leading to high optical loss between optical fibers, especially in the wavelength range of 600 nm to 1700 nm.
Innovation Solution
A structured surface with a plurality of substantially parallel linear structures, including opposing nonlinear facets meeting at a peak, is designed to reduce reflectance to less than 0.5% for both orthogonal polarization states, with an absolute difference in reflectance less than 0.3%, and is applied to the light exit surfaces of optical ferrules to minimize polarization dependence in optical transmittance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional optical ferrule surface is used, then the manufacturing is simple, but the polarization-dependent reflectance is high causing optical loss
Solution Approach 1:
The patent applies curved surfaces by forming structured surfaces with non-linear facets on the optical ferrule exit surfaces. The curved geometry of the structured surface reduces polarization-dependent reflectance by scattering light in multiple directions, thereby improving optical transmittance while maintaining manufacturing feasibility through molding or machining processes.
2Adaptability or versatility
If a structured surface with nonlinear facets is implemented, then polarization insensitive transmittance is achieved, but the manufacturing precision requirements increase
Solution Approach 1:
The patent achieves polarization insensitivity by optimizing geometric parameters of the structured surface, including the curvature radius, facet angles, and pitch of the non-linear structures. By carefully selecting these parameters, the design attains reduced polarization dependence while remaining compatible with standard manufacturing tolerances for molding and machining processes.
3Ease of manufacture
If the structured surface is molded with the ferrule, then manufacturing ease is improved, but the surface finish precision may be compromised
Solution Approach 1:
The patent integrates the structured surface directly into the optical ferrule by molding the anti-reflective structures as an integral part of the ferrule body. This merging of the ferrule and structured surface eliminates separate manufacturing steps, reduces assembly complexity, and ensures consistent geometric parameters while achieving acceptable surface finish for optical applications.
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 structured surface achieves low optical loss (less than 0.7 dB overall) and reduced polarization dependence, resulting in robust and easily manufacturable optical interconnects with minimal reflection and high transmittance across the specified wavelength range.
Implementation Method 1
the structured surface achieves low optical loss (less than 0.7 dB overall) and reduced polarization dependence, resulting in robust and easily manufacturable optical interconnects with minimal reflection and high transmittance
Data Source
AI summary
A structured surface reduces optical reflectance at a predetermined wavelength in a first wavelength range extending from 600 nm to 1700 nm. The structured surface includes a plurality of parallel linear structures arranged along a first direction and extending along an orthogonal second direction. Each linear structure includes opposing nonlinear facets meeting at a peak extending along the second direction. An average spacing between the peaks of adjacent linear structures is less than the predetermined wavelength, such that for light having the predetermined wavelength and incident on the structured surface in a direction substantially perpendicular to the first and second directions, the structured surface has a reflectance Rx<0.5% for light polarized along the first direction and a reflectance Ry<0.5% for light polarized along the second direction, where an absolute value of Rx−Ry is less than 0.3%. An optical ferrule may have an exit surface that includes the structured surface.