Abstract
We report on achieving tuned single mode operation of a multimode semiconductor laser by coupling it to a very-short external cavity with selective feedback. We show that the induced uniform feedback light from the very-short external cavity can induce single-mode oscillation over a broad range of optical feedback. Then by applying selective external to the optimum settings of the single-mode oscillation, we predict tuning of the single-mode output over a wavelength range of ~ 20 nm by detuning the peak wavelength of optical feedback from the central wavelength of the modal gain. The study is based on modeling of the dynamics of multimode semiconductor laser subject to selective optical feedback. The model takes into account mechanisms of both self- and cross-modal gain suppression, and the study is concerned with the very-short external cavity that corresponds to stable continuous-wave (CW) operation.
Highlights
Subjecting semiconductor laser to external optical feedback induces variety of changes in the laser output, ranging between linewidth narrowing to coherence collapse, and from stable CW operation or period-1 oscillations with low noise to chaotic dynamics with noisiest levels [1,2,3,4,5,6,7,8,9,10,11,12,13,14,15]
It was observed in experiments that these modes exhibit hopping, which was attributed to the large value of the linewidth enhancement factor that violates the asymmetric gain suppression (AGS) and competition among these long-wavelength modes [27]
It is motivating to investigate the possibility of achieving stable single-mode oscillation under the predicted stable operation of semiconductor laser coupled with a very-short external cavity
Summary
Subjecting semiconductor laser to external optical feedback induces variety of changes in the laser output, ranging between linewidth narrowing to coherence collapse, and from stable CW operation or period-1 oscillations with low noise to chaotic dynamics with noisiest levels [1,2,3,4,5,6,7,8,9,10,11,12,13,14,15]. They pointed out that the range of feedback that corresponds to single-mode oscillation shifts to weaker values with shortening the external cavity [28]. It is motivating to investigate the possibility of achieving stable single-mode oscillation under the predicted stable operation of semiconductor laser coupled with a very-short external cavity.
Sign-in/Register to view highlights & summary 
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call