Vertical Waveguide Structure for Compact Mach-Zehnder Modulators
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Solution Overview
Problem
Conventional Mach-Zehnder modulators have strict fabrication requirements and large size due to their planar structure, which is challenging to control and optimize.
Innovation Solution
The development of vertically-stacked optical waveguides that replace planar fabrication with vertical resolution, allowing for more precise control and a compact modulator design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional planar Mach-Zehnder modulator structure is used, then optical modulation function is achieved, but fabrication resolution requirements are strict and device size is large
Solution Approach 1:
The patent transitions from a planar two-dimensional waveguide structure to a three-dimensional vertically-stacked configuration. Multiple optical waveguides are stacked vertically with intermediate cladding layers, allowing optical paths to be arranged in the vertical dimension rather than only in the planar horizontal dimension. This dimensional change enables compact integration while maintaining optical performance.
2Ease of manufacture
If planar fabrication process is used, then manufacturing is straightforward, but resolution and controllability are difficult to meet
Solution Approach 1:
The waveguide structure is segmented into distinct vertical layers including lower waveguide cores, intermediate optical cladding layers, and upper waveguide cores. Each layer can be independently fabricated and controlled, with the intermediate cladding serving as separable sections that enable precise positioning and optical coupling control between adjacent waveguide sections.
Solution Approach 2:
By stacking waveguides vertically in the third dimension, the patent achieves better fabrication controllability through vertical layering. The intermediate cladding layers provide clear separation between waveguide sections, enabling independent control of optical coupling and phase modulation in each vertical segment, which is more controllable than planar lateral positioning.
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 approach enhances fabrication controllability and reduces the size of optical modulators, improving their performance and efficiency.
Implementation Method 1
an optical phase shifter that changes the refractive index (n) of the segment of the optical modulation arm thereby causing an accumulated phase of light propagating through the optical modulation arm to change. For example, the optical phase shifter may comprise an electro-optic phase shifter where an electrical field is applied across the optical path
Implementation Method 2
an optical waveguide structure on the major surface. The optical waveguide structure comprises a lower optical core, an upper optical core, and an intermediate optical cladding. One or more of the lower and upper optical cores extends from a first end of the optical waveguide structure to a second end thereof
Implementation Method 3
the intermediate optical cladding separates and is in contact with the optical cores. The optical cores are optically coupled in first and second sections of the optical waveguide structure near the respective first and second ends
Data Source
AI summary
An optical device includes a semiconductor substrate having a major surface, and an optical waveguide structure on the major surface. The optical waveguide structure comprises a lower optical core, an upper optical core, and an intermediate optical cladding, where the upper optical core is vertically above the lower optical core and the intermediate optical cladding separates and is in contact with the optical cores. The optical cores are optically coupled in first and second sections of the optical waveguide structure near the respective first and second ends, and the optical waveguide structure has a parallel pair of optical waveguides extending from the first section to the second section with each of the optical waveguides including one of the optical cores.