Optical Waveguide Y Branch Radiation Light Management
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Solution Overview
Problem
Optical waveguide devices, particularly those with a Y branch structure, experience significant light leakage and degradation of optical characteristics due to a wide branch angle, which is exacerbated by the use of thin substrates like lithium niobate, leading to unstable performance in communication and information processing applications.
Innovation Solution
The optical waveguide device incorporates a first branch portion with a branch angle of 1/35 rad or more, featuring a radiation light guiding waveguide between branched waveguides to direct radiation light outside, and an optical termination portion, such as a conductive member or groove, to absorb or emit guided radiation light, thereby reducing light leakage and maintaining optical characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a Y branch with a great branch angle is used in the optical waveguide, then the device size is reduced and integration is improved, but light leakage increases and optical characteristics are degraded
Solution Approach 1:
A radiation light guiding waveguide is introduced as an intermediary structure between the two branched waveguides. This mediator captures and guides radiation light that would otherwise be lost, channeling it to an optical termination portion. The radiation light guiding waveguide has a specific refractive index lower than the branched waveguides but higher than the surrounding medium, enabling it to effectively capture and transport the radiation light.
Solution Approach 2:
The invention converts the harmful radiation light leakage into a useful resource by guiding it through a dedicated waveguide structure. Instead of allowing light to be lost to the surrounding medium, the radiation light is captured and directed to an optical termination portion, where it can be properly disposed of or reused, thereby turning a loss mechanism into a controlled process.
2Power
If the substrate is thinned to reduce Vπ, then low-voltage operation is achieved, but optical characteristics become unstable due to light leakage
Solution Approach 1:
The radiation light guiding waveguide acts as a mediator that specifically addresses the light leakage problem in thinned substrates. By providing a dedicated path for radiation light between the branched waveguides, it prevents light from escaping into the thin substrate where it would cause instability, thereby maintaining reliable optical characteristics even at reduced substrate thickness.
3Reliability
If a wide separation gap is provided between MZ structures to prevent crosstalk, then electrical signal interference is reduced, but the Y branch gap increases and device size expands
Solution Approach 1:
The invention extracts the radiation light management function from the overall device structure by introducing a dedicated radiation light guiding waveguide. This allows the main MZ structures to be positioned closer together without worrying about radiation light causing crosstalk, as the radiation light is separately managed through its own dedicated waveguide and termination portion.
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 minimizes light leakage and enhances the On/Off extinction ratio of the sub MZ structure, improving optical waveguide device performance even with a great Y branch angle, particularly in thin substrate configurations.
Implementation Method 1
a radiation light guiding waveguide arranged between the two branched waveguides of the first branch portion, and guiding radiation light radiated from between the two branched waveguides at the first branch portion to outside of the optical waveguide
Implementation Method 2
an optical termination portion which absorbs the guided radiation light or emits the guided radiation light to outside of the substrate is arranged in a termination portion of the radiation light guiding waveguide
Data Source
AI summary
An optical waveguide device in which optical characteristics are less degraded even when a branch angle in a Y branch portion of an optical waveguide is great is provided.In an optical waveguide device in which an optical waveguide is formed on a substrate, the optical waveguide includes a first branch portion which branches light into two light rays at a branch angle of 1/35 rad or more, a second branch portion (not illustrated) and a third branch portion (not illustrated) are arranged to be connected to each of two branched waveguides branched from the first branch portion, a radiation light guiding waveguide is arranged between the two branched waveguides of the first branch portion, and guides radiation light radiated from between the two branched waveguides at the first branch portion to the outside of the optical waveguide, and an optical termination portion (an electrode) which absorbs the guided radiation light or emits the guided radiation light to the outside of the substrate is arranged in a termination portion of the radiation light guiding waveguide.