Dispersive self-Q-switching in self-pulsating DFB lasers

• Published in: IEEE journal of quantum electronics Vol. 33; no. 2; pp. 211 - 218
• Main Authors: Sartorius, B., Mohrle, M., Reichenbacher, S., Preier, H., Wunsche, H.-J., Bandelow, U.
• Format: Journal Article
• Language: English
• Published: New York, NY IEEE 01.02.1997; Institute of Electrical and Electronics Engineers
• Subjects: Current density; Dispersion; Distributed feedback devices; Exact sciences and technology; Frequency; Fundamental areas of phenomenology (including applications); Heating; Laser feedback; Laser optical systems: design and operation; Laser tuning; Lasers; Optical devices; Optical tuning; Optics; Physics; Q-switching; Reproducibility of results; Semiconductor lasers; laser diodes; Pulse generation; Reflectors; Semiconductor lasers; Experimental study; Self-pulsing; Q switched laser
• ISSN: 0018-9197; 1558-1713
• DOI: 10.1109/3.552261

Self-pulsations reproducibly achieved in newly developed lasers with two distributed feedback sections and with an additional phase tuning section are investigated. The existence of the dispersive self-Q-switching mechanism for generating the high-frequency self-pulsations is verified experimentally for the first time. This effect is clearly distinguished from other possible self-pulsation mechanisms by detecting the single-mode type of the self-pulsation and the operation of one section near the transparency current density using it as a reflector with dispersive feedback. The operating conditions for generating this self-pulsation type are analyzed. It is revealed that the required critical detuning of the Bragg wavelengths of the two DFB sections is achieved by a combination of electronic wavelength tuning and current-induced heating. The previous reproducibility problems of self-pulsations in two-section DFB lasers operated at, in principle, suited current conditions are discussed, and the essential role of an electrical phase-control section for achieving reproducible device properties is pointed out. Furthermore, it is demonstrated that phase tuning can be used for extending the self-pulsation regime and for optimizing the frequency stability of the self-pulsation. Improved performance of the devices applied as optical clocks thus can be expected.