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Quasi-light Storage for Optical Data Packets
Published on: February 6, 2014
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Modulator-free quadrature amplitude modulation signal synthesis
Zhixin Liu1, Joseph Kakande2, Brian Kelly3
1Optoelectronics Research Centre, University of Southampton, Southampton SO17 1BJ, UK.
Nature Communications
|December 20, 2014
Summary
Directly modulating semiconductor lasers with optical injection locking overcomes frequency chirp limitations. This enables high-speed, complex modulation formats for advanced telecommunication systems.
Area of Science:
- Optoelectronics
- Telecommunications Engineering
- Laser Physics
Background:
- Direct modulation of semiconductor lasers for high-speed telecommunication signals was explored in the 1960s.
- Progress led to 2.5 Gbit/s fiber optic systems, but frequency chirp hindered higher speeds.
- External modulators were required for 10 Gbit/s systems and are prohibitive for >100 Gbit/s coherent systems using complex modulation formats.
Purpose of the Study:
- To investigate optical injection locking of directly modulated semiconductor lasers.
- To generate complex modulation format signals overcoming limitations of direct modulation.
- To demonstrate advantages over current and researched solutions for high-speed telecommunications.
Main Methods:
- Utilized optical injection locking technique.
- Employed directly modulated semiconductor lasers.
- Generated complex modulation formats for telecommunication signals.
Main Results:
- Successfully generated complex modulation format signals.
- Demonstrated distinct advantages over existing solutions.
- Overcame the detrimental frequency chirp issue associated with direct modulation.
Conclusions:
- Optical injection locking is a viable method for high-speed laser modulation.
- This technique enables complex modulation formats for future telecommunication systems.
- Offers a promising alternative to external modulators for >100 Gbit/s coherent systems.
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