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High-speed laser modulation beyond the relaxation resonance frequency limit
Wesley D Sacher1, Eric J Zhang, Brett A Kruger
1Department of Electrical and Computer Engineering and the Institute for Optical Sciences, University of Toronto, Toronto, Ontario M5S 3G4, Canada. wesley.sacher@utoronto.ca
Optics Express
|April 15, 2010
Summary
Coupling modulated lasers (CMLs) overcome traditional bandwidth limits by modulating the output coupler, not the pump rate. This allows for significantly higher modulation speeds, demonstrated with an erbium-doped fiber laser at 1 Gb/s.
Area of Science:
- Optics and Photonics
- Laser Physics
- Nonlinear Optics
Background:
- Conventional lasers are limited in modulation bandwidth by relaxation resonance frequency.
- Modulating the pump rate is the standard method for laser modulation.
- This limitation restricts high-speed optical communication applications.
Purpose of the Study:
- To investigate circumventing the relaxation resonance frequency limit in lasers.
- To explore the potential of coupling modulated lasers (CMLs) for high-speed modulation.
- To demonstrate a proof-of-principle for CMLs in a practical laser system.
Main Methods:
- Proposing and analyzing coupling modulated lasers (CMLs) where the output coupler is modulated.
- Developing theoretical framework for modulation response in CMLs.
- Experimentally demonstrating CML operation with an erbium-doped fiber laser.
Main Results:
- The relaxation resonance frequency limit to laser modulation bandwidth can be circumvented using CMLs.
- The modulation response of CMLs is limited solely by the properties of the output coupler.
- An erbium-doped fiber laser was successfully modulated at 1 Gb/s, exceeding its relaxation resonance frequency by over 10,000 times.
Conclusions:
- CMLs offer a novel approach to significantly enhance laser modulation bandwidth.
- The modulation speed of CMLs is primarily dependent on the output coupler's characteristics.
- CMLs show promise for high-speed optical communication, particularly in microcavity applications.
