Effect of gain saturation on the current-power characteristic of semiconductor laser (original) (raw)

A theoretical investigation of the characteristic temperature T0 for semiconductor lasers

IEEE Journal of Selected Topics in Quantum Electronics, 2003

The temperature dependence of the characteristic temperature T 0 of semiconductor quantum-well lasers is investigated using detailed simulations. The critical-temperature-dependent processes are the optical gain and the nonradiative recombination. The gain model is based on k p theory with the multiple quantum wells in the active layer represented by a superlattice. The Auger process is assumed to be thermally activated. It is shown that, with inclusion of the continuum state filling and interband mixing, the most important features experimentally observed in the temperature dependence of the T 0 value can be explained. The continuum state filling and band nonparabolicity cause a significant deviation from the ideal linear carrier density versus temperature relation for quantum wells. The results are compared to experiment for broad area devices lasing at 980 nm and 1.3, and 1.55 m, and show good agreement over a broad range of temperature.

Nonlinear gain suppression in semiconductor lasers due to carrier heating

IEEE Photonics Technology Letters, 2000

We present a simple model for carrier heating in semiconductor lasers from which the temperature dynamics of the electron and hole distributions can be calculated. Analytical expressions for two new contributions to the nonlinear gain coefficient e are derived, which reflect carrier heating due to stimulated emission and free carrier absorption. In typical cases, carrier heating and spectral holeburning are found to give comparable contributions to nonlinear gain suppression. The results are in good agreement with recent measurements on InGaAsP laser diodes.

Gain saturation in InP∕GaInP quantum-dot lasers

Applied Physics Letters, 2005

We have measured the gain-current and gain-quasi-Fermi level separation characteristics for InP / AlGaInP quantum-dot-laser structures. Saturation of the gain-current characteristics is apparent even though photoluminescence excitation spectroscopy measurements indicate that the 2D states are energetically distant from the dot states. The gain is reduced from the maximum value by the distribution of carriers in the excited dot states, the states in smaller dots and the 2D states.

Carrier heating effects in dynamic-single-frequency GaInAsP-InP laser diodes

IEEE Journal of Quantum Electronics, 1995

The fully self-contained model of a laser diode (LD) under the carrier heating conditions based on the description of a nonequilibrium carrier-phonon-photon system excited by an injection in a P-1-N double heterostructure @I%) is presented. It combines the microscopic approach to the lightcarrier interaction with the macroscopic treatment of the device characteristics and does not for example involve any empirical formulation of nonlinear gain. This model is used to investigate the carrier heating effects in the CW operation, small-signal modulation response and nonlinear picosecond (ps) dynamics of a single-frequency GaInAsP-InP laser. The carrier heating induced suppression of the material gain and enhancement of the intracavity losses are shown to be important for all operational modes. In the CW performance, these effects are found to cause the saturation of lasing and blue shift of the generation wavelength. In the high-frequency response, they are established to ensure an additional mechanism of dynamical carrier-photon coupling and therefore m d i y the modulation behavior of an LD. For nonlinear dynamics, the carrier heating induced perturbation of the gain and losses are shown to lead to deep pulse modulation on a ps timescale. AU the numerical estimations and modeling examples are given for 1.55 pm distributed feedback (DFB) laser operating at mom temperature. It is concluded that carrier heating effects are unwelcome phenomena for CW operation, but they can be engaged to improve the modulation behavior of an LD. AL bandgap narrowing [8]-[lo], and so the carrier heating effects have to be especially significant in the long-wavelength GaInAsP-InP lasers. Carrier heating influence on lasing is frequently described in terms of nonlinear gain [11]-[13], when the mode gain coefficient at a frequency w is written as T~ = Tw,$h(Ne)(l-awNw) [111, [I21 or ^lw = Tu,th(Ne)/(l-k CwNw) [I319 Manuscript