Gas source MBE growth of Tl-containing semiconductors and their application to temperature-insensitive wavelength laser diodes

TlInGaAs/InP system was proposed to fabricate the temperature-insensitive wavelength laser diodes (LDs), which are important in the WDM optical fiber communication system. They were grown by gas source MBE. It was confirmed that the temperature coefficient of the refractive index for TlInGaAs is reduced by the addition/increase of Tl composition in TlInGaAs at both below and above the direct band-gap E₀ edge. It was also confirmed that the temperature coefficient of the E₀ edge is reduced. Current injection pulsed laser operation was obtained up to 310 K. Threshold current density and lasing wavelength at room temperature were 7 kA/cm² and 1665 nm, respectively. We have observed the small temperature variation of the longitudinal-mode peak wavelength as small as 0.06 nm/K, which is smaller than that for the InGaAsP/InP DFB LDs.