Photonic Link Third-Order Distortion Suppression
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Solution Overview
Problem
Conventional photonic links are limited by harmonic distortion and noise figure, which restrict their dynamic range and operational effectiveness, especially in extreme conditions such as lightning strikes, and fail to concurrently suppress intermodulation distortion and noise.
Innovation Solution
A photonic link system comprising an optical emitter, a modulator, a phase shifter, and a controller that splits light into two paths, where the modulator modulates one path based on a radio frequency signal and the phase shifter adjusts the phase of the other path, with the controller determining bias and control signals to maintain specific phase angles and voltages to suppress third-order intermodulation distortion and reduce noise figure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional photonic links are used, then basic signal transmission is achieved, but third-order intermodulation distortion and noise figure limit the dynamic range
Solution Approach 1:
The optical signal is divided into two separate paths: a signal path carrying the modulated optical signal and a local oscillator path carrying the unmodulated optical signal. This segmentation allows independent optimization of each path and enables precise control of the mixing process at the photodetector, thereby suppressing intermodulation distortion while maintaining signal integrity
Solution Approach 2:
A phase shifter is introduced as an intermediary component in the local oscillator path to precisely control the phase relationship between the signal and local oscillator signals. This intermediary element enables accurate phase matching, which is critical for minimizing third-order intermodulation distortion products generated during optical mixing
2Reliability
If conventional photonic links are used, then basic signal transmission is achieved, but noise figure limits the operational effectiveness
Solution Approach 1:
The local oscillator signal is prepared in advance in a separate path with controlled phase and amplitude characteristics before combining with the signal path. This preliminary preparation ensures that the mixing process occurs under optimal conditions, minimizing noise figure and maximizing signal-to-noise ratio in the recovered RF signal
3Power
If high signal gain is applied, then signal strength is improved, but third-order intermodulation distortion increases
Solution Approach 1:
The harmful third-order intermodulation distortion products are extracted and removed from the signal path through precise phase control of the local oscillator. By taking out the phase control function into a separate phase shifter component, the system can selectively eliminate distortion products while preserving the desired signal and fundamental frequency components
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 system effectively suppresses third-order intermodulation distortion and noise figure, enhancing the dynamic range of the photonic link, even under high signal gain conditions, thereby improving its operational performance and reliability.
Implementation Method 1
transmitting light using an optical emitter
Implementation Method 2
a modulator configured to modulate the light transmitted along the first path based on a radio frequency signal
Implementation Method 3
a phase shifter configured to modify a phase of light transmitted along the second path based on a bias voltage
Implementation Method 4
a photodetector coupled to an output of the output coupler
Data Source
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AI summary
Systems, methods, and devices are disclosed for implementing photonic links. Methods include transmitting light using an optical emitter, splitting, using an input coupler, the light into a first path and a second path, the first path being provided to a modulator, and the second path being provided to a phase shifter, and combining, using an output coupler, an output of the modulator and an output of the phase shifter. Methods further include identifying a modulator phase angle that reduces a third order distortion at an output of the output coupler, applying a first bias voltage to a modulator to maintain the identified modulator phase angle, and applying a control signal to the phase shifter to maintain a phase difference between an output of the modulator and an output of a phase shifter.