Photonic RF Transceiver for Millimeter-Wave Phase Stability
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Solution Overview
Problem
Current RF equipment is inadequate for managing transmission and reception of wireless signals across a wide frequency range, leading to insufficient capacity in mobile networks, particularly with the underutilization of the millimeter-wave band due to technical limitations such as unstable high RF oscillators and limited transmission range.
Innovation Solution
A radio frequency signal transceiver utilizing a mode-locked laser, optical splitter, and photonic components to generate and process RF signals, enabling phase-stable transmission and reception without noisy analog up- and down-conversions, allowing for high phase stability and resolution across various carrier frequencies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If electronic RF oscillators are used to generate high-frequency signals, then transmission range can be extended, but phase stability deteriorates due to oscillator instability
Solution Approach 1:
The patent replaces electronic RF oscillators with a photonic system using mode-locked lasers to generate RF signals. The laser generates optical frequencies that are converted to RF through optical-to-electrical conversion, eliminating the need for unstable electronic oscillators at high frequencies while maintaining phase stability through the inherent properties of mode-locked laser operation
Solution Approach 2:
The patent changes the frequency generation approach from direct electronic oscillation to photonic generation followed by optical-to-electrical conversion. This parameter change allows access to higher frequency ranges (millimeter-wave band) while maintaining phase stability through the optical domain where such instability does not exist
2Reliability
If separate RF transceivers are used for each communication bandwidth, then signal transmission quality can be maintained, but device complexity increases
Solution Approach 1:
The patent creates a universal photonic-based RF transceiver that can operate across multiple frequency ranges (from sub-3 GHz to millimeter-wave band) using a single mode-locked laser system. The system can be reconfigured for different bandwidths and applications without requiring separate dedicated transceivers, reducing overall system complexity while maintaining transmission quality
Solution Approach 2:
The patent implements a dynamic, reconfigurable transceiver system where the mode-locked laser can be tuned to generate different RF frequencies and bandwidths as needed. This dynamic capability allows a single transceiver to perform multiple functions across different communication standards and frequency bands, eliminating the need for multiple static transceiver units
3Reliability
If photonic solutions with mode-locked lasers are used to generate RF signals, then phase stability is improved, but manufacturing complexity increases
Solution Approach 1:
The patent uses optical copying techniques where the mode-locked laser generates optical signals that are then converted to electrical RF signals. This copying process from optical to electrical domain allows the system to benefit from the stability of optical generation while delivering electrical signals suitable for RF transmission, managing the complexity through established photonic integration techniques
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 solution enhances system sensitivity, reduces the number of required base stations, and enables gigabit-per-second transmissions in the millimeter-wave band while maintaining compatibility with existing systems, offering flexibility and reconfigurability in cellular communication systems.
Implementation Method 1
an optical amplifier arranged to receive the optical signal from the mode-locked laser and amplify at least two of the modes
Implementation Method 2
a mode-locked laser arranged to output an optical signal having a plurality of phase-locked modes
Implementation Method 3
an optical filter arranged to filter the amplified optical signal to select a first mode and a second mode of the amplified optical signal
Implementation Method 4
a first optical modulator arranged to modulate the first mode and the second mode of the amplified optical signal to generate a pair of phase modulated optical signals
Implementation Method 5
a first photodetector arranged to convert the pair of phase modulated optical signals into a pair of electrical signals
Implementation Method 6
The second optical modulator is arranged to modulate the receiver optical signal with the received radio frequency signal
Implementation Method 7
The optical splitter is arranged to power split the optical signal into a transmitter optical signal and a receiver optical signal
Data Source
AI summary
An RF signal transceiver comprising a mode-locked laser to output an optical signal having a plurality of phase-locked modes, an optical splitter to power split the optical signal into a transmitter optical signal and a receiver optical signal; a transmitter apparatus to receive the transmitter optical signal and comprising an optical filter to select two of the modes, an optical modulator to modulate a part of the transmitter optical signal to form at least one phase modulated optical signal, and a photodetector to heterodyne the phase modulated optical signal with one of the modes without a corresponding phase modulation to form an RF signal for transmission; and a receiver apparatus arranged to receive an RF signal and the receiver optical signal and comprising an optical modulator to modulate the receiver optical signal with the received RF signal; and an optical to electrical signal conversion apparatus to convert the modulated receiver optical signal into a corresponding electrical signal.