Temperature dependence of threshold current density Jth and differential efficiency ηd of high-power InGaAsP/GaAs (λ=0.8 μm) lasers

Abstract

An experimental and theoretical study on temperature dependence of the threshold current density Jth and differential efficiency ηd for the InGaAsP/GaAs laser diodes emitting at λ=0.8 μm was performed. Threshold current density Jth increases and differential efficiency ηd decreases as temperature is increased mainly because of thermal broadening of the gain spectrum. However, the measured temperature dependence of Jth and ηd could not be explained when only this effect was considered. In this letter, the temperature dependence of momentum relaxation rate ℏ/τ of carriers was investigated by performing the photoluminescence study. At high temperature, increase of the momentum relaxation rate ℏ/τ leads to reduction of the gain and mobility and increase of the optical loss, causing higher Jth and lower ηd as experimentally observed. The resulting theoretical model provides a good explanation for the mechanism of the increase of Jth and decrease of ηd.

Thermal Investigation of GaN-Based Laser Diode Package

“…Also, the high junction temperature degrades the optical performance. Thus, it causes a certain problem in potential device failure and reliability [4]- [6]. The high temperature in GaN LDs may stem from Manuscript received January 20, 2006; revised April 9, 2007.…”

Internal cooling in a semiconductor laser diode

“…The average carrier transport energy with respect to the quasi-Fermi energy is given by (1) where the "differential" conductivity gives the contribution of a carrier at energy to the overall conductivity [8].…”

“…EAT MANAGEMENT can be a critical issue in diode laser design, due to the strong temperature dependencies of threshold current, quantum efficiency, and device lifetime [1], [2]. Existing methods for temperature stabilization typically involve placing an external Peltier cooler in the vicinity of the device, either by mounting the device on a heat sink or by fabricating a surface cooler [3].…”

Comparison of gain and threshold current density for InGaAsP/GaAs (λ=808 nm) lasers with different quantum well thickness

“…Detailed fabrication procedures were reported elsewhere. 2,3,7 Laser diodes with cavity lengths varying from 200 to 2700 m were prepared without mirror coating and light-current characteristics were recorded in short pulse operation ͑pulse width 100-400 ns, repetition rate 5-2.5 kHz͒ using an integrating sphere with a Si photodiode. Figure 2 shows threshold current density ͑J th ͒ as a function of cavity length (L).…”

“…10 The optical gain spectrum ͑stimulated emission spectrum͒ strongly depends on the intraband momentum relaxation rate. 7 Since spontaneous emission is broadened in the same physical mechanism ͑momentum relaxation͒ as the stimulated emission, measurement of the former can give the information about how the latter is broadened. In the previous work the spontaneous emission spectrum obtained from photoluminescence was used to extract the momentum relaxation time ϭ0.04 ps in the 300 Å QW structures by comparison with the theoretical calculation.…”