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Ultrafast switch-on dynamics of frequency-tuneable semiconductor lasers
Iman Kundu1, Feihu Wang2, Xiaoqiong Qi3
1School of Electronic and Electrical Engineering, University of Leeds, Leeds, LS2 9JT, UK. I.Kundu@leeds.ac.uk.
Nature Communications
|August 8, 2018
Summary
Researchers observed ultrafast switching in frequency-tuneable semiconductor lasers on picosecond timescales. This reveals fundamental limits on frequency switching, crucial for optical communications and integrated circuits.
Area of Science:
- Optoelectronics
- Semiconductor Lasers
- Photonics
Background:
- Monolithic frequency-tuneable semiconductor lasers are vital for optical communications and photonic integrated circuits.
- Previous studies on ultrafast switching dynamics were limited to nanosecond timescales, hindering understanding of frequency cross-talk reduction.
Purpose of the Study:
- To investigate ultrafast switch-on dynamics, mode competition, and frequency selection in monolithic frequency-tuneable lasers.
- To observe and analyze mode hopping on picosecond timescales and the transition from transient multi-mode to steady-state single-mode emission.
Main Methods:
- Utilized coherent time-domain sampling of laser emission for high-resolution measurements.
- Employed a comprehensive multi-mode, temperature-dependent carrier and photon transport model to explain observed phenomena.
Main Results:
- Observed picosecond-timescale hopping between lasing modes.
- Characterized the temporal evolution from transient multi-mode to steady-state single-mode emission.
- Demonstrated that frequency-switching timescales are fundamentally limited by the laser cavity's Vernier alignment.
Conclusions:
- Coherent time-domain sampling provides unprecedented insight into ultrafast laser dynamics.
- Understanding these picosecond dynamics is essential for optimizing laser performance and minimizing frequency cross-talk in advanced optical systems.
- The Vernier alignment critically influences the ultimate speed of frequency switching in these lasers.
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