Optical Interface Structure Reducing Spatial Coupling Loss
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Solution Overview
Problem
Conventional optical communications through spatial coupling using resin lens members result in higher optical loss due to lower transmittance and increased thickness, which is exacerbated by impurities and misalignment issues.
Innovation Solution
Incorporating a high-transmittance portion, such as a glass member or space, between the optical member and the lens member to reduce optical loss by suppressing the thickness of the lens member, and using a GRIN lens with a refractive index gradation structure to adjust the optical path.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a resin lens member is used for spatial coupling, then workability and cost are improved, but transmittance deteriorates due to impurities and lower material quality
Solution Approach 1:
The patent uses a composite structure combining resin and glass materials. The lens member is made of resin for ease of manufacture, while a glass member with high transmittance is positioned between the optical fiber and lens to compensate for optical loss. This composite approach allows the system to benefit from both the manufacturing advantages of resin and the optical properties of glass.
2Reliability
If the diameter of collimated light beam is increased to tolerate dust and dirt, then reliability is improved, but lens thickness increases causing larger optical loss
Solution Approach 1:
The glass member acts as an intermediary element between the optical fiber and the resin lens. It has a high transmittance (90% or more) that compensates for the optical loss caused by the increased lens thickness. This intermediary component allows the system to maintain both reliability (through larger beam diameter) and low optical loss.
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 configuration effectively reduces optical loss and improves coupling efficiency by allowing propagation in both primary and basic modes, enhancing resistance to optical axis misalignment and maintaining a smaller lens thickness.
Implementation Method 1
using a GRIN lens with a refractive index gradation structure to adjust the optical path
Implementation Method 2
a high-transmittance portion having a higher transmittance than the lens member is disposed between the optical member and the lens member
Data Source
AI summary
An amount of optical loss in spatial coupling can be properly reduced.Provided are optical members, each constituting a light emitter or a light receiver, and a lens member having lens portions. A high-transmittance portion having a higher transmittance than the lens member is disposed between the optical member and the lens member. For example, a light emitter is an optical waveguide that emits an optical signal from one end of the optical waveguide or a light-emitting element that converts an electric signal into an optical signal and emits the signal, and a light receiver is an optical waveguide that receives an optical signal on one end of the optical waveguide or a light-receiving element that converts the received optical signal into an electric signal.