Evanescent Coupler Waveguide for Photonic IC Alignment
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Solution Overview
Problem
The existing methods for measuring photonic integrated circuits (PICs) face challenges such as precise alignment difficulties between optical fibers and diffraction gratings, limited ability to achieve multiple optical inputs and outputs in a small area, and complex verification of structural roughness and etch depth, making it hard to efficiently test silicon optical waveguides.
Innovation Solution
An optical measurement apparatus that includes a substrate with optical waveguide devices connected by connectors, using evanescent couplers to transmit optical signals between the waveguide devices and the PIC, allowing flexible layout and alignment independent of optical fiber size, enabling efficient measurement of multiple ports and array testing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a diffraction grating is used for optical output in photonic IC measurement, then optical signal transmission is achieved, but precise alignment between optical fiber and diffraction grating becomes difficult
Solution Approach 1:
The patent introduces an optical waveguide device as an intermediary component between the optical fiber and the diffraction grating. The optical waveguide extends from the optical fiber to the diffraction grating, serving as a mediator that guides the optical signal without requiring direct alignment between the fiber and grating. This resolves the alignment difficulty by decoupling the positioning requirements of the optical fiber from the diffraction grating.
2Adaptability or versatility
If diffraction grating and optical fiber are used for optical input and output, then optical measurement is enabled, but multiple optical ports cannot be achieved in limited chip area
Solution Approach 1:
The patent utilizes the three-dimensional space within the chip by extending optical waveguides vertically and horizontally through multiple layers. The optical waveguides can route signals through the depth of the chip structure, allowing multiple optical ports to be packed into a smaller footprint by utilizing vertical stacking and lateral routing in addition to planar arrangement.
Solution Approach 2:
The patent divides the optical measurement system into multiple independent optical waveguide devices, each handling specific input or output functions. By segmenting the optical paths into separate waveguide structures, multiple optical ports can be implemented independently within the limited chip area, avoiding the need for large diffraction gratings for each port.
3Measurement precision
If traditional optical measurement method is used for photonic IC, then measurement is possible, but array test becomes difficult
Solution Approach 1:
The patent designs the optical waveguide device with universal interfaces and standardized coupling structures that can accommodate multiple measurement configurations. The same optical waveguide device can be used for individual device characterization, array testing, and various measurement modes, enabling efficient array tests by maintaining consistent measurement protocols across multiple devices without requiring separate alignment procedures for each element.
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 solution allows for precise and flexible measurement of photonic ICs, overcoming alignment issues and enabling dense array testing without size limitations, thus improving the verification of PIC performance and manufacturing process control.
Implementation Method 1
transmitted to the inside of the photonic IC through at least one first evanescent coupler of the photonic IC
Implementation Method 2
transmitted to the at the least one optical waveguide device through at least one second evanescent coupler of the photonic IC
Data Source
AI summary
An optical measurement apparatus configured to measure a photonic integrated circuit (photonic IC) is provided. The optical measurement apparatus includes a substrate, at least one optical waveguide device, a first connector, and a second connector. The at least one optical waveguide device is disposed on the substrate. The first connector and the second connector are connected with the at least one optical waveguide device. An optical signal from a first optical fiber is transmitted to the at least one optical waveguide device through the first connector, transmitted to the inside of the photonic IC though at least one first evanescent coupler of the photonic IC, transmitted to the at least one optical waveguide device through at least one second evanescent coupler of the photonic IC, and transmitted to a second optical fiber through the second connector in sequence.