Grating Optical Coupler With Constructive Interference Filtering
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Solution Overview
Problem
Existing optical couplers for photonic integrated circuits (PICs) face inefficiencies in optical coupling and require separate components for spectral filtering, leading to larger footprints and complex manufacturing processes.
Innovation Solution
An optical coupler that utilizes a grating to achieve constructive interference between diffracted light at two surfaces, integrating spectral filtering and optical coupling functions, and is manufactured using a shared semiconductor layer with other PIC components, simplifying the manufacturing process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If separate components are used for spectral filtering and optical coupling, then spectral filtering function is achieved, but device footprint and complexity increase
Solution Approach 1:
The patent combines spectral filtering and optical coupling functions into a single integrated optical coupler component. The grating structure performs both functions simultaneously: it couples light between waveguides while also acting as a spectral filter through its diffraction properties. This eliminates the need for separate spectral filtering components, reducing device footprint and simplifying the overall system architecture.
Solution Approach 2:
The optical coupler is designed as a multi-functional component that simultaneously provides optical coupling and spectral filtering capabilities. The grating structure serves multiple purposes: it acts as a coupling interface between waveguides, a spectral filter for wavelength selection, and an optical beam shaper. This multi-functionality reduces the number of components needed and simplifies device integration.
2Reliability
If multiple separate components are used for optical coupling, then coupling function is achieved, but manufacturing complexity increases
Solution Approach 1:
The patent integrates multiple optical functions into a single coupler component fabricated using standard semiconductor processes. The grating structure is formed in a single semiconductor layer using conventional lithography and etching techniques, eliminating the need for complex multi-step assembly of separate components. This integration maintains reliable optical coupling while significantly simplifying the manufacturing process.
3Reliability
If conventional optical couplers are used, then optical coupling is achieved, but coupling efficiency is reduced due to losses
Solution Approach 1:
The patent optimizes the grating parameters (period, depth, width, duty cycle) to maximize coupling efficiency and minimize optical losses. By carefully tuning these geometric parameters, the grating achieves optimal diffraction efficiency for the desired wavelength range. The semiconductor material properties are also selected to minimize absorption losses, achieving high overall coupling efficiency.
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 integrated optical coupler enhances coupling efficiency, reduces device size, and simplifies manufacturing by combining spectral filtering and optical coupling into a single component, suitable for applications like optical communications and LIDAR.
Implementation Method 1
light diffracted by a grating is reflected at a first surface, towards a second surface, to interfere constructively with light diffracted by the grating towards the second surface
Implementation Method 2
light diffracted by a grating is reflected at a first surface, towards a second surface, to interfere constructively with light diffracted by the grating towards the second surface
Implementation Method 3
light diffracted by a grating is reflected at a first surface, towards a second surface, to interfere constructively with light diffracted by the grating towards the second surface. The resultant of the interference is subsequently coupled out of the second surface
Data Source
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AI summary
An optical coupler for a photonic integrated circuit, comprising: a grating between a first surface and a second surface; and a first region of a semiconductor layer. A component of the photonic integrated circuit different from the optical coupler comprises a second region of the semiconductor layer. The grating and a distance between the grating and the first surface are each configured such that light diffracted by the grating is reflected at the first surface towards the second surface, to interfere constructively with light diffracted by the grating towards the second surface.