Optical Resonator PSK Demodulation Without Coherent Clock
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Solution Overview
Problem
Conventional high order PSK demodulators require a locally coherent clock source and complex optics, making them costly and intricate for phase-encoded optical signal demodulation.
Innovation Solution
The use of optical resonators, such as Fabry-Perot filters or micro-rings, to convert phase-encoded optical signals into intensity-encoded signals, allowing for demodulation without a coherent clock source and simplifying the receiver system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional high order PSK demodulators use a local reference source and multiple detectors, then phase-encoded information can be recovered, but the system complexity and cost increase significantly
Solution Approach 1:
The patent extracts and removes the local reference source (local oscillator) from the coherent detection system. By using optical resonators with high Q-factors, the system achieves phase-to-intensity conversion without requiring a separate local reference beam, thereby simplifying the receiver architecture while maintaining demodulation capability
Solution Approach 2:
The patent introduces optical resonators as intermediary elements that mediate the conversion process. The resonators act as frequency-selective intermediaries that convert phase-modulated signals into intensity-modulated signals, enabling simplified detection without direct coherent mixing
2Measurement precision
If conventional demodulators use frequency controlled lasers and multiple detectors, then accurate phase measurement is achieved, but the number of components and digital signal processing requirements increase
Solution Approach 1:
The patent replaces the mechanical/optical complex system of multiple detectors and local oscillators with a resonator-based system. The optical resonators perform the frequency selection and phase-to-intensity conversion function that would otherwise require multiple coherent detectors and sophisticated digital signal processing algorithms
Solution Approach 2:
The optical resonators perform multiple functions simultaneously: they act as frequency-selective filters, phase-to-intensity converters, and signal amplifiers (through their high Q-factor). This multi-functionality eliminates the need for separate components for each function, reducing the overall number of elements required
3Loss of information
If phase modulation receivers use precision optics and local oscillators, then information recovery is enabled, but the system becomes significantly more complex compared to amplitude modulation receivers
Solution Approach 1:
The patent changes the operational parameter of the optical signal from phase domain to intensity domain through the resonator conversion process. By operating the resonators at specific Q-factors and coupling conditions, phase information is transformed into intensity variations that can be detected with simple photodetectors, avoiding the need for complex phase-sensitive detection hardware
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 reduces the complexity and cost of the receiving system while enabling demodulation across a broad range of modulation rates, accommodating various encoding techniques and modulation schemes.
Implementation Method 1
The optical resonator is configured to accumulate resonant optical signal energy inside the optical resonator based on the received optical signal
Implementation Method 2
a first disturbance in the first output optical signal energy responsive to a phase transition in the arriving optical signal
Data Source
AI summary
Optical signal receivers and methods are provided that include first and second optical resonators, each of which receives a portion of an arriving optical signal. The first optical resonator is tuned to a carrier wavelength and accumulates resonant optical signal energy whose output is disturbed responsive to a transition in the arriving optical signal. The second optical resonator is detuned from the carrier wavelength but also exhibits a disturbed output responsive to the transition in the arriving optical signal. Detectors detect the output disturbances from the two optical resonators to determine characteristics of the transition in the arriving optical signal.