Stability of pulse emission and enhancement of intracavity second-harmonic generation in self-mode-locked quantum cascade lasers

Author

Soibel, Alexander ; Capasso, Federico ; Gmachl, Claire ; Peabody, Milton L. ; Sergent, A.Michael ; Paiella, Roberto ; Sivco, Deborah L. ; Cho, Alfred Y. ; Liu, H.C.

Author_Institution

Bell Labs., Lucent Technol., Murray Hill, NJ, USA

Volume

40

Issue

3

fYear

2004

fDate

3/1/2004 12:00:00 AM

Firstpage

197

Lastpage

204

Abstract

We report the observation of stable pulse emission and enhancement of intracavity second-harmonic generation (SHG) in self-mode-locked quantum cascade (QC) lasers. Down-conversion of the detector signal by heterodyning with an RF signal allows the direct observation of the pulsed laser emission in the time domain and reveals a stable train of pulses characteristic of mode-locked lasers. The onset of self-mode locking in QC lasers with built-in optical nonlinearity results in a significant increase of the SHG signal. A pulse duration of ∼12 ps is estimated from the measured increase of the SHG signal in pulsed emission compared to the power expected for the SHG signal in CW emission. This value is in good agreement with the pulse duration deduced from the optical spectral width.

Keywords

heterodyne detection; laser cavity resonators; laser mode locking; laser stability; optical harmonic generation; optical pulse generation; quantum cascade lasers; spectral line breadth; CW emission; RF signal; SHG; built-in optical nonlinearity; detector signal downconversion; heterodyning; intracavity second-harmonic generation; mode-locked lasers; nonlinear optics; optical spectral width; pulse duration; pulse emission stability; pulse generation; pulsed laser emission; self-mode-locked quantum cascade lasers; semiconductor lasers; time domain emission; ultrafast optics; Laser mode locking; Laser stability; Optical harmonic generation; Optical mixing; Optical pulse generation; Optical pulses; Pulse measurements; Quantum cascade lasers; RF signals; Stimulated emission;

fLanguage

English

Journal_Title

Quantum Electronics, IEEE Journal of

Publisher

ieee

ISSN

0018-9197

Type

jour

DOI

10.1109/JQE.2003.823036

Filename

1271351