Tunable Ring Resonator Waveguide Loss Reduction
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Solution Overview
Problem
Planar optical waveguides suffer from significant attenuation due to sidewall roughness, leading to broadening of filter responses and reduced transmission in optical filters, which existing compensation strategies only partially address and often increase power and noise consumption.
Innovation Solution
The use of a combination of single-mode and multi-mode waveguide segments in optical filters, where multi-mode waveguides are employed in substantially straight segments and single-mode waveguides in bent segments, with tapered transitions to minimize excitation of higher-order modes and reduce waveguide losses, thereby improving filter performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If planar optical waveguides are used to transmit optical signals, then optical signal transmission is achieved, but significant attenuation occurs due to sidewall roughness
Solution Approach 1:
The patent applies different waveguide cross-sectional areas to different locations in the optical path. Specifically, the waveguide has a first cross-sectional area in straight sections and a second, smaller cross-sectional area in bent sections. This local differentiation reduces sidewall roughness effects in bent regions where they are most problematic, thereby reducing overall optical signal attenuation while maintaining transmission quality.
2Manufacturing precision
If conventional waveguide designs are used in optical filters, then filter construction is achieved, but filter response broadening and reduced transmission occur
Solution Approach 1:
The patent implements local quality by varying the waveguide cross-sectional area along its length. Straight sections maintain a larger first cross-sectional area for low-loss transmission, while bent sections use a smaller second cross-sectional area to reduce sidewall roughness effects. This localized optimization prevents filter response broadening and maintains high transmission through the optical filter.
Solution Approach 2:
The waveguide is segmented into distinct straight sections and bent sections with different cross-sectional areas. This segmentation allows each section to be optimized for its specific function: straight sections for efficient light propagation and bent sections for directional changes with minimized loss. The segmented design directly addresses filter response characteristics and transmission efficiency.
3Loss of energy
If waveguide cross-sectional area is reduced to minimize loss, then attenuation is reduced, but waveguide performance deteriorates
Solution Approach 1:
Rather than uniformly reducing the waveguide cross-sectional area, the patent applies the smaller second cross-sectional area only in bent sections where sidewall roughness causes the most loss. Straight sections maintain the larger first cross-sectional area to preserve waveguide performance. This localized approach reduces overall attenuation while maintaining reliable waveguide performance in regions where it matters most.
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 approach significantly reduces overall filter losses while maintaining signal integrity, avoiding the excitation of higher-order modes and minimizing chromatic dispersion, resulting in improved filter performance with reduced attenuation and noise.
Implementation Method 1
The bent waveguide sections change a propagation direction of received light by more than 1/2 of a right angle
Implementation Method 2
Planar optical waveguides are employed in optical devices to transmit an optical signal
Implementation Method 3
The changing includes converting a propagation mode of the optical signal from a fundamental mode in the multi-mode waveguide segment to a different fundamental mode in the curved segment
Data Source
AI summary
An apparatus, including an optical ring resonator having a waveguide ring with substantially straight waveguide segments and bent waveguide segments. The bent waveguide segments are optically coupled to the substantially straight waveguide segments and have optical cores with substantially smaller cross-sectional areas than the substantially straight waveguide segments. The bent waveguide segments change a propagation direction of received light by more than ½ of a right angle.