Dynamics of multimode diode lasers with strong, frequency-selective optical feedback.
The dynamical behavior of a class of multimode semiconductor diode lasers with emission wavelength around 980 nm is investigated both experimentally and numerically in the presence of strong, frequency-selective optical feedback provided by a fiber Bragg grating. The focus is set on the switching between broad- and narrow-band optical spectra, on chaotic transitions, and on the loss of frequency locking between laser and grating. Laser and feedback parameters are chosen in the typical ranges pertaining to wavelength stabilization in erbium-doped fiber amplifiers for telecommunication applications. An improved set of rate equations, which allows for arbitrary feedback levels and includes experimentally measured gain and linewidth enhancement factor, is studied analytically and numerically.