Polarization Control Device Using MMI and Tapered Waveguide
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Solution Overview
Problem
Existing polarization rotation devices face challenges in manufacturing stability and reproducibility due to alignment issues between core and cladding layers, leading to variations in polarization rotation characteristics.
Innovation Solution
A polarization control device with a multi-mode interference structure, including phase shifters and tapered waveguides, is used to adjust phase differences between TE and TM polarized light modes, enabling efficient polarization conversion and reducing optical loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If high-precision alignment is performed to make the etched side face of the SiON film exactly coincide with the side face of the first core layer, then the manufacturing precision is improved, but the device complexity and difficulty of manufacture increase due to the multi-step alignment process
Solution Approach 1:
The patent merges the alignment function into the multi-mode interference device structure itself. The side faces of the multi-mode interference device are designed to automatically align with the side faces of the optical waveguides through their integrated construction, eliminating the need for separate high-precision alignment steps between SiON film and core layer
Solution Approach 2:
The multi-mode interference device structure provides self-alignment through its geometric design. The side faces of the device naturally coincide with the side faces of the connected optical waveguides without requiring external alignment adjustments or complex positioning mechanisms
2Manufacturing precision
If the side face of the SiON film is made to coincide with the side face of the first core layer through multiple etching and deposition steps, then the structural precision is improved, but the productivity decreases due to the time-consuming multi-step process
Solution Approach 1:
The patent segments the manufacturing process into two distinct parts: the multi-mode interference device is formed as an integrated structure with predetermined side face geometry, and the optical waveguides are separately formed. This segmentation allows parallel processing and eliminates sequential alignment steps, improving productivity while maintaining precision
Solution Approach 2:
The multi-mode interference device is formed in advance with its side faces precisely defined during the device fabrication process. This preliminary formation of the alignment reference structure enables subsequent optical waveguides to be aligned to it without requiring additional high-precision alignment operations
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 device achieves stable and reproducible polarization conversion with reduced optical loss, allowing for effective polarization control and independent waveguide operation.
Implementation Method 1
a multi-mode interference device having a primary-side end face including a first port and a second port
Implementation Method 2
a tapered waveguide having one end and the other end, the one end being optically coupled to the first port in the secondary-side end face of the multi-mode interference device. The tapered waveguide has a width decreasing in a direction from the one end to the other end
Data Source
AI summary
A polarization control device includes a MMI device having primary-side and secondary-side end-faces; a first phase shifter optically coupled to a first port in the primary-side end-face; a first optical waveguide optically coupled via the first phase shifter to the first port in the primary-side end-face; a second optical waveguide optically coupled to a second port in the primary-side end-face; and a tapered waveguide optically coupled to a first port in the secondary-side end-face. The first and second ports in the primary-side end-face are located on first and second axes, respectively. The first port in the secondary-side end-face is located on a third axis located between the first and second axes. The first, second, and third axes extend in a direction from the primary-side end-face to the secondary-side end-face. The tapered waveguide has a width decreasing in a direction from one end to the other end of the tapered waveguide.