The effect of the temperature for cw DH(Double Heterojunction) GaAs/GaAlAs diode laser is investigated by measuring the spectral output in a spectrometer and the total output power in a power-meter.
The dependence of temperature on the threshold current is described by $J_th=J_0exp(T/θ_0)$,$(θ_0=288.3 k)$ and experimentally confirmed. As the temperature increases from -5℃ to 45℃, the threshold current increases almost linearly from 77 mA to 85.2 mA.
The spectral output is analyzed by using Czerny Turner spectrometer. Above the threshold current, the wavelength of the mode of maximum power does not shift through the injection current increases. But the wavelength of the mode of maximum power does increase linearly in accordance with the experimentally obtained equation Δλ/ΔT=2.7A/℃.
Below the threshold current, the net gain coefficient is obtained by the measurement of the ratio of the maximum to minimum of the Fabry-Perot resonance of the spontaneous emission. As the injection current increases, the net gain coefficient increases and the gain profile becomes more broad. As the temperature increases, the net gain coefficient decreases and the gain profile moves to long wavelength.