Angled Periodic Segmented Waveguide for Reduced Return Loss
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Solution Overview
Problem
Existing spot size converters with periodic segmented waveguides experience increased return losses due to their grating-like structure, particularly across specific wavelength ranges, limiting their effectiveness in efficiently coupling optical fibers and photonic integrated circuits without degrading optical performance.
Innovation Solution
An angled periodic segmented waveguide design is introduced, where gaps between waveguide segments are oriented at non-zero angles relative to the waveguide width, reducing the reflection of light back towards the source and thereby minimizing return losses across multiple wavelength ranges while maintaining effective spot size conversion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a periodic segmented waveguide with gaps parallel to the waveguide width is used for spot size conversion, then the waveguide can effectively couple optical fibers and photonic integrated circuits, but return loss increases due to the grating-like structure
Solution Approach 1:
The patent applies asymmetry by orienting the gaps at a non-zero angle relative to the waveguide width direction. This asymmetric configuration breaks the grating-like periodicity that causes constructive interference and high return loss peaks, while still maintaining the spot size conversion function through the tapered waveguide structure.
Solution Approach 2:
The patent changes the geometric parameter of the gaps from being parallel to the waveguide width (zero angle) to being at a non-zero angle. This parameter change modifies the optical interaction characteristics, reducing the return loss by preventing the formation of strong grating modes while preserving the mode size conversion capability.
2Object-generated harmful factors
If the waveguide gaps are oriented at non-zero angles to reduce return loss, then return loss peaks are reduced across wavelength ranges, but the spot size conversion effectiveness may be compromised
Solution Approach 1:
The patent uses segmentation by dividing the waveguide into multiple sections separated by gaps. The tapered geometry combined with angled gaps creates a gradual mode transformation through these segments, maintaining conversion effectiveness while the angled orientation prevents harmful grating effects.
Solution Approach 2:
The patent applies local quality by having the waveguide width vary continuously along its length (tapered structure), creating different local optical properties at different positions. This gradual change in local geometry enables effective spot size conversion while the angled gaps locally disrupt the periodicity that causes high return 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
The angled waveguide design significantly reduces return loss peaks and maintains optical performance, allowing for efficient spot size conversion over a broader range of wavelengths without increasing insertion loss, thus enhancing the compatibility of optical fibers and photonic integrated circuits.
Implementation Method 1
reducing the reflection of light back towards the source and thereby minimizing return losses
Implementation Method 2
a spot size converter may include: a tapered periodic segmented waveguide (PSW)... capable of expanding or contracting a mode of light in one or more spatial dimensions
Data Source
AI summary
A spot size converter may include a tapered periodic segmented waveguide (PSW). The tapered PSW may include a plurality of waveguide segments defined by a plurality of gaps between the plurality of waveguide segments. The plurality of gaps may be at one or more angles that are not substantially parallel to a direction of a width of the tapered PSW. The direction of the width of the tapered PSW may be substantially perpendicular to a direction in which light passes through the tapered PSW.