Diverging Grating Coupler for Low-Loss Optical Power Distribution
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current methods for coupling an external optical beam to on-chip photonic sub-circuits suffer from substantial nonlinear losses, limiting the optical power that can be coupled and the number of sub-circuits that can be powered from a single external light source.
Innovation Solution
A diverging grating coupler is used to couple an external optical signal into a planar waveguide layer, creating a diverging phase front, and a plurality of channel waveguides with individually optimized waveguide apertures and transition structures to capture a predetermined portion of the optical power, allowing for efficient distribution to multiple on-chip photonic sub-circuits without significant losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a single external laser is used with on-chip splitter distribution network, then cost is reduced, but optical power is insufficient to compensate for branching losses and on-chip losses
Solution Approach 1:
The invention segments the optical power distribution by using multiple external laser sources instead of a single laser with splitters. Each laser directly couples to its own grating coupler, eliminating the need for power splitting and avoiding the associated losses. This segmentation approach maintains cost-effectiveness while ensuring sufficient optical power at each destination.
Solution Approach 2:
The invention merges the functions of multiple laser sources and grating couplers into a coordinated system where each component works independently but contributes to the overall optical distribution. This combining approach allows each laser to operate at optimal power levels without the need to overcome splitting losses in a centralized distribution network.
2Power
If high optical power is coupled to on-chip submicron waveguide, then more on-chip sub-circuits can be powered, but nonlinear processes cause substantial losses
Solution Approach 1:
The invention applies local quality by using individualized grating couplers for each laser source, where each coupler is optimized for its specific laser's characteristics and positioning. This local optimization allows each coupling point to operate at optimal efficiency, distributing power effectively without concentrating excessive power in a single waveguide that would trigger nonlinear losses.
Solution Approach 2:
The grating coupler acts as an intermediary device that transforms the optical field from the external laser into a form suitable for efficient coupling into the on-chip waveguide. This intermediary structure enables controlled power transfer, allowing high optical power to be coupled efficiently while maintaining waveguide power levels below the threshold for significant nonlinear losses through proper design and positioning.
3Power
If conventional grating coupler is used, then coupling is achieved, but coupling efficiency is insufficient for high power distribution
Solution Approach 1:
The invention changes key parameters of the grating coupler design, including the grating period, depth, fill factor, and orientation, to optimize coupling efficiency for high power applications. By adjusting these parameters, the coupler achieves maximum power transfer efficiency, minimizing coupling losses and enabling effective high-power distribution to multiple on-chip sub-circuits.
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 enables a higher optical power to be coupled to multiple on-chip sub-circuits, increasing the number of sub-circuits that can be powered from a single external light source while minimizing optical losses, and allows for tailored power splitting ratios between sub-circuits.
Implementation Method 1
a diverging grating coupler configured to couple the external optical signal and to thereby create an on-chip diverging optical beam in the waveguide layer
Data Source
Figure 1
Figure 2
Figure 3
AI summary
An optical device is provided for coupling an external optical signal into a plurality of on-chip photonic sub-circuits provided on a substrate. The optical device comprises: a planar waveguide layer on the substrate; a diverging grating coupler configured to couple the external optical signal to the waveguide layer and to thereby create an on-chip diverging optical beam in the waveguide layer; and a plurality of channel waveguides formed in the waveguide layer. Each of the plurality of channel waveguides comprises a waveguide transition structure having a waveguide aperture oriented towards the grating coupler. For each of the plurality of channel waveguides the position and the width of the corresponding waveguide aperture and the angle and the shape of the waveguide transition structure are individually selected to capture a predetermined portion of the on-chip diverging optical beam.