Active mode locking of broadband quantum cascade lasers

• Published in: IEEE journal of quantum electronics 2004-07, Vol.40 (7), p.844-851
• Main Authors: Soibel, A., Capasso, F., Gmachl, C., Peabody, M.L., Sergent, A.M., Paiella, R., Hwang, H.Y., Sivco, D.L., Cho, A.Y., Liu, H.C., Jirauschek, C., Kartner, F.X.
• Format: Article
• Language: English
• Subjects: Chemical lasers; Chemical technology; Exact sciences and technology; Fundamental areas of phenomenology (including applications); Laser mode locking; Laser optical systems: design and operation; Lasers; Modulation, tuning, and mode locking; Nonlinear optics; Optical design; Optical pulse generation; Optical pulses; Optics; Physics; Quantum cascade lasers; Semiconductor lasers; Semiconductor lasers; laser diodes; Space vector pulse width modulation; Ultrafast optics; Ultrafast processes; optical pulse generation and pulse compression
• ISSN: 0018-9197; 1558-1713
• DOI: 10.1109/JQE.2004.830186

Active mode locking in broadband quantum cascade (QC) lasers with a repetition rate of about 14.3 GHz has been achieved through the modulation of the laser bias current. At low driving currents, the active mode locking in broadband QC lasers resembles the active mode locking in single-wavelength QC lasers, while at high driving currents, the mode locking properties are governed by the broad spectral gain of these lasers. At high bias currents, the active modulation excites Fabry-Perot modes across the entire gain spectrum from 6.7 to 7.4 /spl mu/m, with clear evidence of mode locking. The spectral width of the optical gain in the broadband QC lasers exceeds 2 THz and indicates the potential for generating subpicosecond pulses.