Optical Waveguide Mode Conversion for Low-Loss Thin-Plate Modulators
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Solution Overview
Problem
Existing optical modulators face challenges in achieving miniaturization, low optical loss, and long-term stability, particularly in thin-plate structures, due to complex manufacturing processes and material durability issues.
Innovation Solution
An optical waveguide device is designed with optical waveguides formed on separate substrates, where one substrate has a conversion portion to adjust the optical mode field diameter, and the substrates are directly bonded without an adhesive layer, using methods like ion implantation, ion exchange, or ultrashort pulse laser to form connecting waveguides, ensuring smooth mode transitions and reduced optical loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the substrate is thinned to 2 μm or less to achieve miniaturization and reduce drive voltage, then the device size and drive voltage are reduced, but the optical mode field diameter becomes significantly different from optical fiber (1 μm vs 10 μm), causing optical loss increase of 14 dB or more
Solution Approach 1:
An optical waveguide made of organic material is introduced as an intermediary component between the thin substrate waveguide and the optical fiber. This intermediate waveguide has an optical mode field diameter that can be adjusted to match both the thin substrate waveguide (1 μm) and the optical fiber (10 μm), thereby reducing optical loss at the connections without requiring substrate thickening
Solution Approach 2:
The optical mode field diameter parameter of the intermediate waveguide is specifically designed to be between 1 μm and 10 μm, creating a gradual transition in mode field diameter. This parameter change allows for smooth optical mode conversion and reduces the abrupt mismatch that causes 14 dB or more optical loss
2Loss of energy
If horizontally or vertically tapered optical waveguides are provided to convert optical mode field diameter, then optical loss due to coupling with optical fiber is reduced, but the manufacturing process becomes complicated
Solution Approach 1:
An optical waveguide made of organic material is used instead of complex tapered structures. Organic materials can be easily deposited and patterned using standard semiconductor manufacturing processes, providing a simpler manufacturing path while achieving the desired mode field diameter conversion and reducing optical loss
3Ease of manufacture
If an optical waveguide made of organic material is provided to convert optical mode field diameter, then the manufacturing process becomes relatively easy, but long-term stability such as photo-durability of organic materials becomes a problem
Solution Approach 1:
The optical waveguide device uses a composite structure combining inorganic materials (substrate, electrodes) with organic material (intermediate waveguide). The organic waveguide is specifically designed for mode field diameter conversion where its optical properties are optimized, while the inorganic substrate provides structural stability and electrical functionality, achieving both ease of manufacture and long-term stability
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 results in an optical waveguide device that is compact, exhibits low optical loss, and maintains long-term stability, facilitating efficient optical coupling and modulation.
Implementation Method 1
at least a part of the optical waveguide A has a conversion portion that converts an optical mode field diameter
Implementation Method 2
a connecting optical waveguide of the optical waveguide A, which connects the optical waveguide A and the optical waveguide B
Implementation Method 3
formed by using any one of ion implantation, ion exchange, or an ultrashort pulse laser
Implementation Method 4
formed by using any one of ion implantation, ion exchange, or an ultrashort pulse laser
Implementation Method 5
the second substrate has an optical modulation portion that modulates a light wave propagating through the optical waveguide B
Data Source
AI summary
To provide an optical waveguide device that is small, has low optical loss, and has long-term stability. Provided is an optical waveguide device in which an optical waveguide A (20) is formed on a first substrate (2), an end portion of the first substrate has an input portion that inputs a light wave into the optical waveguide A or an output portion that outputs a light wave from the optical waveguide A, an optical waveguide B (10) is formed on a second substrate (1), the second substrate has an optical modulation portion that modulates a light wave propagating through the optical waveguide B, and at least a part of the optical waveguide A (20) has a conversion portion (20) that converts an optical mode field diameter.