Silicon Electro-Optic Phase Modulator with Segmented Doping
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Solution Overview
Problem
The integration of high-performance silicon electro-optic modulators for chip-scale optical interconnections is hindered by the need for efficient light modulation with low power dissipation and high bandwidth, which existing technologies have not adequately addressed due to challenges in minimizing absorption losses and leakage currents.
Innovation Solution
A silicon electro-optic phase modulator structure is developed, featuring a silicon-on-insulator layer with n-doped and p-doped regions, intrinsic regions, and a thin high-k dielectric layer to confine light and reduce leakage currents, utilizing free carrier dispersion for refractive index modulation and incorporating a waveguide cladding layer for optical signal confinement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional silicon electro-optic modulator structures are used, then device integration is achieved, but absorption losses and leakage currents increase
Solution Approach 1:
The modulator structure is segmented into distinct functional regions: n-doped regions, intrinsic regions, and p-doped regions arranged in alternating layers. This segmentation allows each region to perform its specific function optimally - the doped regions provide electrical contact and carrier injection, while the intrinsic regions provide low-loss optical propagation paths, thereby reducing overall absorption losses while maintaining device performance
Solution Approach 2:
Different regions of the modulator are assigned different doping concentrations and material properties tailored to their specific functions. The n-doped and p-doped regions have high carrier concentrations for effective electrical control, while the intrinsic regions have low carrier concentrations to minimize absorption losses. This local optimization of material properties reduces energy loss while preserving modulator functionality
2Ease of manufacture
If conventional modulator structures are used, then manufacturing is simplified, but leakage currents increase
Solution Approach 1:
The modulator employs a segmented layered structure with intrinsic regions positioned between doped regions. This segmentation creates natural barriers that block leakage current paths while maintaining manufacturability through standard semiconductor fabrication processes. The intrinsic regions act as intrinsic diodes that prevent carrier injection into adjacent doped regions, reducing leakage currents without complicating the manufacturing process
Solution Approach 2:
The intrinsic regions serve as intermediary layers between the n-doped and p-doped regions. These intrinsic regions mediate the electrical and optical interaction by providing a low-loss optical path while blocking direct electrical contact between oppositely doped regions, thereby reducing leakage currents while maintaining ease of manufacture through conventional fabrication techniques
3Speed
If high-performance modulation is achieved, then bandwidth increases, but power dissipation increases
Solution Approach 1:
The modulator structure segments the optical path into multiple intrinsic regions separated by thin doped layers. This segmentation allows for distributed modulation across multiple interfaces, enabling high bandwidth through cumulative phase modulation while keeping the carrier concentration in each individual doped region low, thereby reducing power dissipation per interface and overall power consumption
Solution Approach 2:
The invention transitions from planar modulation to three-dimensional layered modulation by stacking multiple intrinsic-doped-intrinsic sequences vertically. This dimensional change enables increased bandwidth through multiple modulation interfaces while maintaining low power dissipation by keeping each interface thin and the doped region thickness optimized for minimal carrier injection requirements
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 enables efficient phase modulation with reduced power consumption and increased bandwidth by minimizing absorption losses and leakage currents, facilitating the integration of optical interconnections at the chip scale.
Implementation Method 1
a thin high-k dielectric layer to confine light
Implementation Method 2
utilizing free carrier dispersion for refractive index modulation
Data Source
AI summary
An electro-optic (EO) phase modulator is disclosed. The EO phase modulator includes: an insulating layer; a central optical waveguide over the insulating layer; a first region having a first type doping adjacent to a first sidewall of the central optical waveguide; a second region having a second type doping opposite to the first type doping adjacent to a second sidewall of the central optical waveguide opposite to the first sidewall; and a first dielectric layer passing through the central optical waveguide from a top surface of the central optical waveguide to a bottom surface of the central optical waveguide. A method of manufacturing the same is disclosed as well.