Angled Optical Modulator Element for Compact Chip Area
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Solution Overview
Problem
Conventional optical modulator elements face challenges in miniaturization due to spatial constraints and high-frequency wave signal transmission line delays, leading to increased module size and interference between optical paths and transmission lines.
Innovation Solution
The optical modulator element design includes a first and second optical modulator disposed on a semiconductor substrate with angled Mach-Zehnder waveguides, reducing the chip size by minimizing the gap between modulators and optimizing high-frequency wave transmission line routing to avoid interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If two optical modulators are disposed in parallel with each other, then the module can support multi-level phase-shift keying and polarization-division multiplexing, but the gap between modulators increases the chip area
Solution Approach 1:
The patent transitions from a parallel arrangement (one-dimensional spacing) to an angled arrangement where modulators are disposed at angles relative to each other. This dimensional change in the spatial configuration allows the modulators to be positioned closer together, reducing the gap and chip area while maintaining the necessary optical path separation for multi-level phase-shift keying and polarization-division multiplexing functionality
2Reliability
If high-frequency wave transmission lines are routed to ensure equal delay length, then signal synchronization is maintained, but the transmission line area increases
Solution Approach 1:
The patent employs asymmetric routing of high-frequency wave transmission lines to the first and second optical modulators. Instead of forcing equal-length symmetric paths that consume excessive area, the transmission lines are routed with different lengths and configurations that achieve the required signal synchronization through compensatory design, thereby reducing the overall transmission line area while maintaining reliability
3Reliability
If high-frequency wave transmission lines bypass optical paths, then signal interference is avoided, but the module area increases
Solution Approach 1:
The patent resolves the interference issue by transitioning from a two-dimensional planar layout where transmission lines must bypass optical paths (consuming excessive area) to a three-dimensional configuration. The high-frequency wave transmission lines are routed above or below the optical paths through different layers or vertical spacing, eliminating signal interference while maintaining compact module dimensions without requiring large bypass routes
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 results in a smaller chip area for the optical modulator element and minimizes high-frequency wave signal crosstalk, allowing for more compact and efficient optical modulation modules.
Implementation Method 1
A light beam received by such a Mach-Zehnder optical modulator is split into two paths by an optical coupler
Implementation Method 2
The incident light beam is modulated with a phase shift that occurs due to refractive index variations caused by an electric filed applied to a medium
Data Source
AI summary
An optical modulator element includes first and second optical modulators, an optical input terminal, and a branch coupler. Each of the first and second optical modulators includes a pair of Mach-Zehnder waveguides, a first optical coupler to split rays from the branch coupler into the pair of Mach-Zehnder waveguides, and a second optical coupler to combine rays transmitted through the pair of Mach-Zehnder waveguides. The first and second optical modulators are disposed in such a manner that a traveling direction of rays propagating through the pair of Mach-Zehnder waveguides of the first optical modulator and a traveling direction of rays propagating through the pair of Mach-Zehnder waveguides of the second optical modulator are angled toward each other.