A unified approach to study the thermal dynamics in multilongitudinal modesemiconductor lasers

A unified approach to study the effects of temperature on the static and dy namic characteristics ties of multilongitudinal mode laser diode has been a ttempted by incorporating an analogous heat flow circuit in the electrical equivalent circuit model of the laser diode. The effect of temperature on t he threshold current, longitudinal mode behavior, and the thermal fluctuati ons are analyzed by simulating the circuit for dc sweep and transient condi tions using the circuit analysis program PSPICE. The analysis shows that th e side modes dominate at higher temperatures resulting in a shift in output optical wavelength. The optical output of each mode val-ies with temperatu re in a parabolic fashion. In transient simulations, thermal fluctuations a re found to increase with temperature and decrease with operating frequency . The small signal ac simulation predicts a sharp decrease in the 3dB bandw idth of the device with temperature. Furthermore, the presence of package p arasitics also decreases the bandwidth.