PIC Lens and Reflector Coupling for Glass Waveguide Alignment
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Solution Overview
Problem
There is no well-established solution for optically coupling a photonic integrated circuit (PIC) to a glass substrate waveguide, leading to alignment challenges and signal loss due to stringent mode size mismatch.
Innovation Solution
Incorporating a spot size converter (SSC) and an emitting lens on the PIC to expand the optical mode size, coupled with a reflective optical element to steer the light orthogonally onto a glass substrate waveguide, allowing for relaxed alignment and simplified assembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If direct optical coupling is used between PIC and glass substrate waveguide, then device complexity is reduced, but alignment precision deteriorates due to stringent mode size mismatch
Solution Approach 1:
The patent introduces an optical coupling structure comprising a lens and a spot size converter as intermediary elements between the PIC and glass substrate waveguide. The lens focuses light from the PIC while the spot size converter transforms the optical mode size to match the waveguide, enabling efficient coupling without direct contact and relaxing alignment tolerances.
Solution Approach 2:
The spot size converter dynamically changes the optical mode size parameter to match between the PIC output and the waveguide input. By transforming the beam waist and mode field diameter, it adapts the optical parameters to achieve compatibility between components with different mode sizes, thereby improving alignment precision.
2Reliability
If mode size is reduced to match waveguide, then coupling efficiency is improved, but alignment budget deteriorates becoming more stringent
Solution Approach 1:
The optical coupling structure acts as a mediator that decouples the strict mode size matching requirement from the alignment process. The lens and spot size converter work together to maintain high coupling efficiency while providing a larger alignment budget by reducing sensitivity to lateral and angular misalignments.
Solution Approach 2:
The patent transitions from direct lateral coupling to a three-dimensional coupling approach using a lens with specific focal length and a spot size converter positioned at different heights. This dimensional transformation allows the system to achieve both high coupling efficiency and relaxed alignment requirements by operating in multiple spatial dimensions.
3Ease of operation
If spot size converter is added to expand mode size, then alignment complexity is reduced, but device complexity increases
Solution Approach 1:
The patent combines the lens and spot size converter into an integrated optical coupling structure that is mounted directly on the PIC. This merging approach consolidates multiple functions (focusing, mode transformation, and coupling) into a single compact assembly, reducing alignment complexity while managing device complexity through integration.
Solution Approach 2:
The optical coupling structure serves multiple functions simultaneously: the lens focuses light from the PIC, the spot size converter transforms the optical mode, and the combined structure provides mechanical support and alignment references. This multi-functionality reduces the need for separate components and simplifies the overall assembly process.
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 solution enables efficient optical coupling with reduced alignment complexity and signal loss, facilitating the integration of PICs with glass substrate waveguides.
Implementation Method 1
an emitting lens disposed on the PIC to emit light from the at least one waveguide
Implementation Method 2
a reflective optical element to steer the light orthogonally onto a glass substrate waveguide
Data Source
AI summary
An electronic device comprises a photonic integrated circuit (PIC) including at least one waveguide, an emitting lens disposed on the PIC to emit light from the at least one waveguide in a direction substantially parallel to a first surface of the PIC, and an optical element disposed on the PIC and having a reflective surface configured to direct light emitted from the emitting lens in a direction away from the first surface of the PIC.