Grating Coupler Assembly With Transparent Optical Path Filler
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Solution Overview
Problem
The existing surface coupling systems, such as those described in PTL 1, suffer from a sharp decrease in optical coupling efficiency due to slight alignment errors between the edge-emitting laser and the optical integrated circuit.
Innovation Solution
A grating coupler comprising a first optical waveguide chip, a second optical waveguide chip, and a transparent member, where the optical path between the chips is filled with the transparent member, reducing variations in light incident positions and enhancing alignment tolerance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If surface coupling is used between edge-emitting laser and optical integrated circuit, then optical coupling can be achieved, but alignment error sensitivity causes sharp decrease in coupling efficiency
Solution Approach 1:
The patent introduces a transparent member (intermediary substance) filled in the optical path between the first and second waveguide gratings. This intermediary reduces the variation in incident position of light on the gratings when relative position changes occur, thereby reducing the sharp decrease in coupling efficiency that would otherwise result from alignment errors. The transparent member acts as a mediator that buffers the sensitivity to misalignment.
Solution Approach 2:
The patent modifies the optical path parameters by filling it with a transparent member, which changes the optical characteristics (refractive index, light propagation path) to reduce sensitivity to alignment errors. This parameter change in the optical path enables wider acceptable alignment error while maintaining coupling efficiency.
2Reliability
If tight alignment is maintained between chips, then coupling efficiency is high, but device complexity and assembly difficulty increase
Solution Approach 1:
The transparent member serves as an intermediary that decouples the strict alignment requirement between the two chips. By introducing this intermediary substance in the optical path, the system can maintain high coupling efficiency even when chips have slight misalignments, thereby reducing the complexity of alignment control and assembly procedures.
3Ease of manufacture
If alignment tolerance is increased, then assembly becomes easier, but optical coupling efficiency decreases
Solution Approach 1:
The transparent member acts as a compensating intermediary that allows the system to achieve both goals: wider alignment tolerance (easier assembly) and maintained coupling efficiency. The intermediary substance reduces the variation in light incident position on the waveguide gratings, enabling the system to tolerate larger alignment errors without significant efficiency loss.
Solution Approach 2:
By changing the optical path parameters through the introduction of a transparent member, the patent enables the system to maintain high coupling efficiency even with increased alignment tolerance. This parameter modification in the optical path allows easier assembly while preserving optical performance.
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 grating coupler achieves a wider acceptable alignment error, maintaining consistent optical coupling efficiency despite minor positional discrepancies.
Implementation Method 1
Light emitted from the active portion is diffracted by the first surface grating and coupled to the second surface grating
Implementation Method 2
Between the first light incident/exit surface and the second light incident/exit surface, an optical path of the light within an operating wavelength range of the grating coupler is filled with the transparent member
Data Source
AI summary
A grating coupler includes: a first optical waveguide chip; a second optical waveguide chip; and a transparent member. The first optical waveguide chip includes a first substrate, a first waveguide grating, and a first chip end surface. The second optical waveguide chip includes a second waveguide grating and a second chip top surface. Between a first light incident/exit surface of the first optical waveguide chip and a second light incident/exit surface of the second optical waveguide chip, an optical path of light within an operating wavelength range of the grating coupler is filled with the transparent member.