Tapered Edge Coupler With Pedestal Alignment for Low-Loss PIC Coupling
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Solution Overview
Problem
Coupling losses in photonic integrated circuits (PICs) occur due to thickness differences and misalignment between edge couplers and optical transmitters or receivers, leading to inefficient energy transfer.
Innovation Solution
An edge coupler with a thickness that tapers from a narrow end to a wide end, coupled to a waveguide, and a pedestal for vertical alignment of optical transmitters or receivers, ensuring precise alignment and reduced coupling losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If an edge coupler is used to couple waveguide to optical transmitter/receiver, then energy transfer is enabled, but coupling losses occur due to thickness differences and misalignment
Solution Approach 1:
The patent introduces a vertical dimension solution by creating a pedestal structure that elevates the optical transmitter or receiver above the substrate plane. This dimensional change allows the optical component to be vertically aligned with the edge coupler, compensating for horizontal misalignment and thickness differences, thereby reducing coupling losses without requiring extremely precise lateral positioning.
Solution Approach 2:
The pedestal acts as an intermediary structure between the substrate and the optical transmitter/receiver. It provides mechanical support while enabling precise vertical positioning, serving as a mediator that bridges the gap between the substrate-mounted waveguide and the elevated optical component, thus facilitating efficient coupling.
2Ease of manufacture
If edge coupler thickness matches waveguide thickness, then manufacturing is simplified, but misalignment with optical transmitter/receiver increases coupling losses
Solution Approach 1:
Instead of adjusting edge coupler thickness to match the optical transmitter/receiver (which would complicate manufacturing), the patent moves the solution to the vertical dimension by introducing a pedestal. This allows the edge coupler to maintain its standard waveguide-matching thickness while the pedestal provides the necessary height adjustment for alignment, decoupling the manufacturing simplicity from the alignment precision requirements.
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 tapered edge coupler and pedestal design minimizes coupling losses by aligning optical components vertically, enhancing energy transfer efficiency in PICs.
Implementation Method 1
An edge coupler with a thickness that tapers from a narrow end to a wide end, coupled to a waveguide... couples the optical transmitter or receiver to the waveguide
Data Source
AI summary
An edge coupler has a wide end, a narrow end, and a tapering thickness. The narrow end is coupled to a waveguide in a photonic integrated circuit (PIC). The wide end is coupled to an optical transmitter or receiver. The edge coupler thickens by tapering downward into the buried oxide layer of a BOX substrate. An upper surface of the edge coupler may be planar. A pedestal may be formed in the oxide layer so that a laser diode mounted on the pedestal will be vertically aligned to the edge coupler. Alternatively, the pedestal may be formed in a substrate under the oxide layer so that the core of an optical fiber mounted on the pedestal will be vertically aligned to the edge coupler. The pedestal may be in a cavity that facilitates horizontal alignment between the laser diode, optical fiber, or other such device and the edge coupler.