Experimental stability diagram of a diode laser subject to weak phase-conjugate feedback from a rubidium vapor cell

• Published in: IEEE journal of quantum electronics Vol. 35; no. 4; pp. 577 - 582
• Main Authors: Andersen, O.K., Fischer, A.P.A., Lane, I.C., Louvergneaux, E., Stolte, S., Lenstra, D.
• Format: Journal Article
• Language: English
• Published: New York, NY IEEE 01.04.1999; Institute of Electrical and Electronics Engineers
• Subjects: Bifurcation; Delay; Diode lasers; Exact sciences and technology; Feedback; Four-wave mixing; Frequency; Fundamental areas of phenomenology (including applications); Laser feedback; Laser optical systems: design and operation; Laser stability; Lasers; Locking; Mirrors; Nonlinear optics; Nonlinear Sciences; Optical feedback; Optics; Phase change materials; Phase conjugation, optical mixing, and photorefractive effect; Phase conjugation, optical mixing; photorefractive and kerr effects; Physics; Pump lasers; Relaxation oscillations and long pulse operation; Rubidium; Semiconductor lasers; laser diodes; Spectra; Stability; Frequency locking; Four-wave mixing; Laser feedback; Laser stability; Relaxation oscillation; Experimental study; Rubidium; Laser diodes; Phase conjugation; Semiconductor lasers; Hopf bifurcation; Mirrors; Nonlinear optics
• ISSN: 0018-9197
• DOI: 10.1109/3.753662

We report on a systematic experimental investigation of the dynamical behavior of a diode laser subject to delayed feedback from a phase-conjugating mirror based on nearly-degenerate four-wave mixing in rubidium vapor. We present the first experimental stability diagram for this system. In the weak feedback regime, with feedback levels up to -30 dB, me demonstrate locking to the pump frequency with a reduced linewidth smaller than 8 MHz. In contrast to a laser with external injection, and contrary to predictions made for phase-conjugate feedback, the extent of this locking region is found to be limited. For increased feedback rates, the laser leaves the locking region and enters an unstable region through a series of multiple sidebands spectra. This is associated with self-excitation of the relaxation oscillation, and the observed scenario suggests a series of period-doublings after an initial Hopf bifurcation.