Stray Light Suppression in Photonic Integrated Circuits
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Solution Overview
Problem
Photonic integrated circuits (PICs) face issues with stray light generation due to non-guided radiation modes, which can lead to erroneous signals and interference in applications requiring stable polarization states, particularly in high-density integrated systems where components are closely located, causing performance degradation.
Innovation Solution
The integration of an array of waveguide collectors aligned to collect stray light and direct it towards damping areas where the light energy is converted into heat, using techniques such as forward or inverse tapers to optimize light collection and absorption, thereby suppressing stray light by over 20dB.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If components are integrated closely in high-density PICs, then productivity and scalability are improved, but stray light generation increases causing harmful interference
Solution Approach 1:
The patent extracts harmful stray light from the main optical path by introducing separate collector waveguides that specifically capture radiation modes. These collector waveguides are positioned to receive stray light from components like Y-junctions and bend waveguides, separating the harmful radiation from the main signal path and preventing it from interfering with other components.
Solution Approach 2:
The patent introduces absorptive material as an intermediary substance within the collector waveguides. This material serves as a mediator that converts the captured stray light energy into heat, effectively neutralizing the harmful radiation without allowing it to propagate further through the circuit.
2Device complexity
If stray light is not suppressed, then device complexity is reduced, but measurement precision and signal accuracy deteriorate due to erroneous signals
Solution Approach 1:
The patent segments the optical circuit into functional regions by introducing dedicated collector waveguides alongside the main signal waveguides. This segmentation allows the system to handle stray light management separately from the main optical signal transmission, enabling precise control over harmful radiation without complicating the core signal path.
3Object-generated harmful factors
If collector waveguides are added to suppress stray light, then stray light suppression is improved, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The patent merges the stray light collection function with the existing waveguide structure by integrating collector waveguides alongside main signal waveguides. Both types of waveguides are fabricated using the same processes and materials, combining multiple functions into a unified structure that manages both signal transmission and stray light suppression efficiently.
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 effectively mitigates stray light interference, enhancing the operational stability and accuracy of PICs by reducing erroneous signals and improving the overall performance of photonic integrated circuits.
Implementation Method 1
direct it towards damping areas where the light energy is converted into heat
Data Source
Figure 1A~1B
Figure 1C~1D
Figure 2
AI summary
In a photonic integrate circuit (PIC) architecture, non-guided stray light that is radiated from components, junctions, discontinuous and scattering points in an integrated optic device, may be received by an integrated waveguide structure in the path of the stray radiation. The integrated waveguide structure may comprise a plurality of collectors that are configured to collect the non-guided stray light from the radiating source. Each of the collectors may comprise an integrated waveguide with a front end that is tapered to increase the mode-field size and pointed toward the stray light source, and with a back end that is connected to a secondary waveguide. The collectors are placed in the path of the stray light and aligned in the propagation direction of the stray light. The collected stray light is guided to a light energy damper through the second waveguide for converting light energy into heat.