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Parity-time-symmetric optoelectronic oscillator.
1Microwave Photonics Research Laboratory, School of Electrical Engineering and Computer Science, University of Ottawa, Ottawa, Ontario K1N 6N5, Canada.
Science Advances
|June 12, 2018
Summary
Optoelectronic oscillators (OEOs) generate low-phase noise microwave signals. A novel parity-time (PT) symmetry approach achieves stable single-mode oscillation, simplifying OEO implementation without narrow filters.
Area of Science:
- Physics
- Electrical Engineering
- Photonics
Background:
- Optoelectronic oscillators (OEOs) generate high-frequency, low-phase noise microwave signals using a feedback loop.
- Long optical fibers in OEOs improve signal quality but lead to closely spaced oscillation modes, requiring complex filters for single-mode operation.
- Existing ultranarrowband filters for mode selection are difficult to implement and lack stability.
Purpose of the Study:
- To achieve stable single-mode oscillation in OEOs without using ultranarrowband optical filters.
- To overcome the challenge of mode selection in OEOs for simplified implementation.
- To generate ultralow phase noise microwave signals.
Main Methods:
- Utilized a novel concept based on parity-time (PT) symmetry.
- Implemented two identical feedback loops, one with gain and the other with a matched loss.
- Analyzed the PT-symmetric OEO theoretically and verified its performance through experimentation.
Main Results:
- Achieved stable single-mode oscillation in the OEO.
- Demonstrated ultralow phase noise microwave signal generation.
- Successfully eliminated the need for ultranarrowband optical filters for mode selection.
Conclusions:
- Parity-time (PT) symmetry provides an effective method for achieving single-mode oscillation in OEOs.
- This PT-symmetric approach simplifies OEO design and implementation.
- The method enables robust generation of ultralow phase noise microwave signals.
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