Intrinsic performance-limiting instabilities in two-level class-B broad-area lasers

Stabilization of class-B broad-area laser emission by external optical injection

“…Specifically, with widely used top-hat pumping profile output emission turns to be intrinsically driven to the filamentary state due to the high sensitivity to boundaries [10][11][12][13][14]. We examine the impact of external optical injection on these effects in the next section.…”

“…We fix for definiteness the following parameter values identical to those previously used in [10] Pumping level r0 and frequency detuning δ were considered to be the control parameters.…”

“…In considered Maxwell-Bloch equations such inherent instabilities are especially well-pronounced in class-B case resulting in filamentary dynamics even in boundaries-free cavity [10]. The solitary class-B lasers exhibit the traveling-wave instability that emerges at nonzero, but even very small values of frequency detuning and initiates the filamentary behavior of the laser output.…”

“…We also take for the characteristic parameters of the unstable modes the next estimates [10]: for the unstable wavenumbers With allowance for these assumptions and splitting real and imaginary parts in (A1), we get the expressions for the unstable branch of the dispersion curve at the lowest order of magnitude: …”

“…It was also found that in broad-area class-B lasers filamentary instabilities become especially wellpronounced. Specifically, class-B broad-area lasers were shown to exhibit two main types of intrinsic transverse instability mechanisms leading to the filamentary dynamics of the laser output [10]. Firstly, the homogeneous output profile turns to be intrinsically unstable in class-B limit due to the bulk instability even in the absence of the phase-amplitude coupling in the active medium and independently from the boundary conditions.…”