Optical Link for EHF Signal Transmission
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Solution Overview
Problem
Extreme High Frequency (EHF) communication systems face challenges such as signal attenuation in coaxial cables, increased size, weight, and power consumption of RF components, and difficulties in downstream receiver processing like downconverting and signal addressing, which are exacerbated by chromatic dispersion-induced signal fading in optical systems.
Innovation Solution
A communications device utilizing an optical source, a Mach-Zehnder modulator, optical waveguides, and an optical-to-electrical converter to modulate and filter RF signals, reducing signal degradation by generating and selecting sidebands, and downconverting EHF signals to an intermediate frequency with reduced phase noise and chromatic dispersion effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If EHF signals are transmitted over coaxial cable, then signal transmission is achieved, but large attenuation effects occur
Solution Approach 1:
The patent introduces an optical carrier signal as an intermediary medium to transmit EHF signals. Instead of directly transmitting EHF signals over coaxial cable, the system modulates the EHF signal onto an optical carrier, transmits it over optical fiber, and then recovers it. This intermediary optical transmission medium eliminates the large attenuation problems associated with coaxial cable transmission of EHF signals.
2Reliability
If optical heterodyne approaches are used, then EHF signal transmission is achieved, but chromatic dispersion-induced signal fading occurs
Solution Approach 1:
The patent extracts and removes the problematic optical carrier frequency components through optical filtering. By using optical bandpass filters to select specific sidebands and reject the optical carrier and other unwanted frequencies, the system eliminates the chromatic dispersion effects that cause signal fading, while preserving the transmitted EHF information.
3Productivity
If RF devices are used in EHF systems, then signal processing is achieved, but size, weight, and power consumption increase to undesirable levels
Solution Approach 1:
The patent replaces traditional RF electronic processing components with optical processing components. By using optical modulators, optical filters, and optical detectors instead of RF amplifiers, mixers, and frequency synthesizers, the system achieves the same signal processing functions with reduced size, weight, and power consumption, while operating in the optical domain.
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
The solution enables efficient transmission and processing of EHF signals with reduced signal degradation, improved size, weight, and power consumption, and mitigates chromatic dispersion-induced fading, allowing for reliable and efficient communication over long distances.
Implementation Method 1
an optical source configured to generate an optical carrier signal
Implementation Method 2
a modulator, for example, a Mach-Zehnder modulator, coupled to the optical source and configured to modulate the optical carrier signal with an input signal
Implementation Method 3
an optical waveguide coupled to the transmitter device
Implementation Method 4
The receiver device comprises an optical splitter
Implementation Method 5
a first waveguide path coupled to the optical splitter and configured to filter at least one sideband from the modulated optical carrier signal
Implementation Method 6
an optical-to-electrical converter. The optical-to-electrical converter is coupled to the first and second waveguide paths and is configured to generate an output signal comprising a replica of the input signal
Data Source
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AI summary
A communications device includes a transmitter device including an optical source configured to generate an optical carrier signal, and a modulator coupled to the optical source and configured to modulate the optical carrier signal with an input signal having a first frequency, an optical waveguide coupled to the transmitter device, and a receiver device coupled to the optical waveguide. The receiver device includes an optical splitter, a first waveguide path coupled to the optical splitter and configured to filter a sideband from the modulated optical carrier signal, a second waveguide path coupled to the optical splitter and configured to generate a selected sideband from selectable sidebands based upon the modulated optical carrier signal, and an optical-to-electrical converter coupled to the first and second waveguide paths and configured to generate an output signal including a replica of the input signal at a second frequency based upon the selected sideband.