Tunable SSB Modulators Using Poled Electro-Optic WGM Resonators
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Solution Overview
Problem
Existing optical resonators, particularly whispering gallery mode (WGM) resonators, face limitations in achieving tunable single sideband (SSB) modulation due to their reliance on external polarization control and frequency tuning within the constraints of the free spectral range (FSR), which complicates applications requiring independent frequency tuning of signal modulation.
Innovation Solution
The use of periodically poled electro-optic materials with different poled domains in WGM resonators allows for internal material structure to support SSB operation through cross-modulation between orthogonally polarized whispering gallery modes, enabling independent frequency tuning of the modulation signal without external polarization control, using RF or microwave signals and DC bias voltage to adjust the electro-optic effect.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If external polarization control and frequency tuning are used in WGM resonators, then SSB modulation can be achieved, but device complexity increases and frequency tuning is constrained by the free spectral range
Solution Approach 1:
The patent extracts the polarization control function from external components and integrates it into the resonator's internal material structure through periodic poling. The electro-optic material itself provides the necessary polarization differentiation, eliminating the need for external polarization controllers and reducing overall device complexity while maintaining frequency tuning capability.
Solution Approach 2:
The patent employs periodically poled electro-optic materials that combine multiple functions within a single integrated structure. The composite nature of the periodically poled material enables simultaneous polarization control, frequency tuning, and SSB modulation generation, replacing multiple separate components with one unified element.
2Adaptability or versatility
If frequency tuning is performed within the constraints of the free spectral range, then resonator stability is maintained, but tuning range and flexibility are limited
Solution Approach 1:
The patent introduces dynamic frequency tuning capability through voltage-controlled electro-optic modulation. By applying external voltage to the electro-optic material, the resonator's resonant frequency can be dynamically adjusted beyond the fixed FSR constraints, enabling flexible frequency tuning while maintaining stability through controlled modulation rather than uncontrolled frequency drift.
Solution Approach 2:
The patent changes the operating parameters of the electro-optic material through periodic poling and voltage application. This allows the resonator to operate at frequencies beyond the traditional FSR limits by modifying the material's electro-optic properties, thereby expanding the tuning range while maintaining stable resonant operation through controlled parameter adjustment.
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 enables agile frequency tuning of SSB modulation, allowing for efficient signal modulation and generation applications by decoupling frequency tuning from the FSR of the resonator, resulting in simplified device structures and improved tunability across various frequency ranges.
Implementation Method 1
an optical resonator structured to include different poled electro-optic domains and to support whispering gallery modes circulating in the optical resonator to effectuate a single sideband (SSB) on only one side of the laser frequency
Implementation Method 2
using RF or microwave signals and DC bias voltage to adjust the electro-optic effect
Implementation Method 3
An optical coupler can be used to couple light into or out of the WGM resonator via this evanescent field
Implementation Method 4
different poled electro-optic domains to support SSB operation through cross-modulation between orthogonally polarized whispering gallery modes
Data Source
AI summary
Photonic devices and techniques based on tunable single sideband (SSB) modulation in whispering gallery mode resonators formed of different poled electro-optic domains and to support whispering gallery modes circulating in the optical resonator to effectuate a single sideband (SSB) on only one side of the laser frequency without having a mirror image sideband on the other side of the laser frequency.