Optoelectronic Oscillator Feedback Loop for Side-Mode Noise Suppression
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Solution Overview
Problem
Existing optoelectronic oscillators with band-pass filters and feedback loops suffer from increased phase noise due to the electrical oscillator created by the band-pass filter and feedback loop, which is not present in optoelectronic oscillators alone.
Innovation Solution
Incorporating a feedback loop in the electric section of the optoelectronic oscillator with a band-pass filter, where the amplification of the entire loop is set to be less than 1, and using a quality multiplier with a band-pass filter to suppress oscillation, while allowing phase noise reduction by adjusting the amplification and phase settings within the feedback loop.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a band-pass filter with feedback loop is added to form an electrical oscillator, then the oscillator loop is stabilized and mode selection is improved, but the phase noise increases
Solution Approach 1:
The system is divided into two separate oscillators: an optical oscillator and an electrical oscillator. The optical oscillator generates the main signal while the electrical oscillator (band-pass filter with feedback loop) acts as a separate mode-selection element. This segmentation allows each oscillator to perform its specialized function without the harmful interactions that cause phase noise in a single combined oscillator.
Solution Approach 2:
An intermediary coupling mechanism is introduced between the optical and electrical oscillators. The electrical oscillator does not directly drive the optical oscillator but instead couples to it through a controlled interaction, allowing the electrical oscillator to provide mode selection stability while minimizing its direct influence on the optical oscillator's phase noise characteristics.
2Reliability
If the amplification of the feedback loop is increased to stabilize oscillation, then the oscillation stability is improved, but the phase noise from the electrical oscillator increases further
Solution Approach 1:
The system employs dynamic coupling where the interaction strength between the optical and electrical oscillators can be adjusted. By dynamically controlling the coupling mechanism, the system can achieve stable oscillation when needed while minimizing the electrical oscillator's phase noise contribution during critical signal generation phases.
Solution Approach 2:
The coupling parameters between the optical and electrical oscillators are optimized to achieve the desired balance. By adjusting parameters such as coupling strength and phase relationship, the system achieves stable oscillation output while minimizing the harmful phase noise from the electrical oscillator section.
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 configuration reduces phase noise to a level closer to that of a standalone optoelectronic oscillator, achieving a narrower bandwidth and lower insertion loss, while maintaining the stability of the oscillation mechanism.
Implementation Method 1
a band-pass filter with a feedback loop
Implementation Method 2
A light source 1 which is selected as a laser, for instance, generates a signal carrier 2 of an optoelectronic oscillator to be transferred via optical delay line
Implementation Method 3
By means of the photo detector 7 said carrier 2 is removed from the signal 6 of the optoelectronic oscillator
Data Source
Figure 1~2
AI summary
The present invention refers to a device for optoelectronic oscillator side-mode suppression, comprising an optical section, an electric section, and a band-pass filter with a feedback loop. According to the present invention is provided that a feedback loop (12) which is connected in parallel to a band-pass filter (9) in an electric section (E) comprises means (13) for coupling signal, means (14) for dividing signal, and means (15) for signal processing, wherein the amplification of a loop provided by the filter (9) and the feedback loop (12) is less than "1"