4.3.3 Population and the Laser Analog Model
in the Quasi-Stationary Mode
The structures of the laser analog model (Figs. 4.7 and 4.13) show that the pumping
system is the system of the negative feedback with inertia for the control or
restriction of the oscillation amplitude of the field strength taking into consideration
the laser power E
2
0n ¼ Re E n E
Ã
n
Â
Ã
. At that, the following expression is true for the
population:
Fig. 4.13 (a) The structure of the laser model with the closed loop of the positive feedback and the
active medium (OA). The optical oscillations of the field strength E L. in affect to the OA input. After
amplification we have in the optical OA output E L. out . (b) The laser analog model in quasistationary mode presented with the help of the control operator transfer function
K L ( p 00 ) ¼ E L. out /E L. in and the nonlinear element S(E n ). (c) The laser analog model in the dipole
approximation in the quasi-stationary small-signal mode
158
4 Semiclassical Theory and Laser Differential Equations for Optoelectronic. . .