Large-signal modulation of MQW long-wavelength lasers
The large signal modulation response of a 1.3 mum InGaAsP 4-well laser of the Fabry-Perot type is investigated The current density is assumed to take the form J = J(O)+J(M)sin(omegat) where J(O) is the steady state current density above threshold and J(M) is allowed to take values such that the modulation depth, m, may not satisfy the condition m < < 1. The time evolution of the photon density shows that the output power may be sinusoidal when m < < 1, i.e. small signal modulation, low and very high frequencies. At intermediate frequencies, in the gigahertz range, the output power is far from sinusoidal and may shou, the characteristic oscillations due to the large signal transients. The resonance frequency is seen to decrease as the modulation depth increases, the worst case being when the nonlinear saturation effects are not included.
lasers semiconductors simulation