Optical Modulator Shielding Radiation Light
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Solution Overview
Problem
In optical modulators with thin plates, radiation light and propagation light are not efficiently separated, leading to deterioration of the extinction ratio and misalignment during fiber connection due to overlapping light spots.
Innovation Solution
The optical modulator incorporates a shielding means, such as a concave portion or through-hole with a light absorbing material, and a high refractive index region, strategically positioned to separate radiation light from propagation light, and uses a Mach-Zehnder type optical waveguide configuration with directional couplers or X cross waveguides to effectively isolate the radiation light.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a thin plate structure is used to reduce substrate thickness for velocity matching and driving voltage reduction, then velocity matching between microwave and light wave is improved and driving voltage is reduced, but radiation light and propagation light spots overlap causing deterioration of extinction ratio and misalignment during fiber connection
Solution Approach 1:
The patent divides the thin plate into multiple layers with different refractive indices (first thin plate with higher refractive index, second thin plate with lower refractive index). This segmentation creates distinct optical paths that separate radiation light from propagation light, preventing spot overlap and maintaining extinction ratio while preserving velocity matching benefits.
Solution Approach 2:
The patent applies different refractive index properties to different regions of the thin plate structure. The first thin plate region has higher refractive index to guide propagation light, while the second thin plate region has lower refractive index to allow radiation light to escape. This local differentiation of optical properties enables simultaneous achievement of velocity matching and light separation.
2Speed
If a thin plate structure is used to reduce substrate thickness for velocity matching and driving voltage reduction, then velocity matching between microwave and light wave is improved and driving voltage is reduced, but misalignment during fiber connection occurs due to overlapping light spots
Solution Approach 1:
The patent segments the thin plate into layered structures with different refractive indices, which spatially separates radiation light and propagation light paths. This segmentation prevents radiation light from contaminating the fiber input position, thereby improving alignment precision during fiber connection while maintaining velocity matching.
Solution Approach 2:
By assigning different refractive index characteristics to different local regions of the thin plate, the patent ensures that propagation light remains confined to the waveguide region while radiation light is directed away from the fiber connection area. This local quality differentiation maintains both velocity matching and connection alignment precision.
3Ease of manufacture
If radiation light is not separated from propagation light in thin plate structure, then manufacturing is simpler, but loss of optical modulator increases due to radiation light input into fiber
Solution Approach 1:
The patent introduces a segmented layered structure where the first and second thin plates with different refractive indices create distinct optical zones. This segmentation adds minimal manufacturing complexity while effectively preventing radiation light from entering the fiber, thereby reducing optical loss without significantly complicating the manufacturing process.
Solution Approach 2:
The patent modifies local optical properties in specific regions of the thin plate by creating layers with different refractive indices. This local quality adjustment strategically directs radiation light away from the fiber input while maintaining simplicity in other areas, achieving loss reduction with minimal impact on manufacturing ease.
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
This configuration efficiently separates radiation and propagation light, reducing loss and improving the extinction ratio, and simplifies the manufacturing process by allowing for precise control over light paths, thus enhancing the optical modulator's performance and yield.
Implementation Method 1
a thin plate made of a material having an electrooptic effect and having a thickness of 20 μm or less
Implementation Method 2
a shielding means, such as a concave portion or through-hole with a light absorbing material
Data Source
AI summary
An optical modulator capable of efficiently separating radiation light and propagation light from each other or removing the radiation light in the optical modulator to suppress loss of the optical modulator and deterioration of an extinction ratio, including a thin plate of a material having an electrooptic effect and a thickness of 20 μm or less; an optical waveguide formed in a top surface or a bottom surface of the thin plate; and a modulation electrode formed in the top surface of the thin plate to modulate light which propagates in the optical waveguide, the optical waveguide has an optical junction portion in which a plurality of optical waveguide portions are joined together and, for shielding a portion of radiation light radiated from the optical junction portion, a concave portion or through-hole in the thin plate.