1.3 /spl mu/m quantum dot DFB lasers

Using laterally patterned metal gratings, single mode operation of 1.3 /spl mu/m InAs/GaInAs quantum dot lasers has been achieved. At room temperature the lasers exhibit threshold currents as low as 17 mA, output powers of up to 8 mW (cw) and very stable single mode emission with side mode suppression ratios of well above 40 dB.

Introduction

For optical data transmission in local area networks (LAN) semiconductor lasers emitting at 1.3µm are used, because at this wavelength dispersion in fibers is minimal. (Ga)InAs/AlGaAs quantum dot lasers grown on GaAs substrates are a promising alternative to the currently used InGaAsP/InP lasers. In addition to the technological advantages of GaAs based lasers, the special properties of quantum dot lasers such as a weak temperature dependence of the emission wavelength [1] and low threshold current densities [2] are of great significance for telecommunication applications. Since the first realization of GaAs based quantum dot lasers emitting at 1.3 µm by Liu et al. [2], their performance has improved at an enormous rate over a very short period of time [3], [4]. First devices with properties and dimensions suitable for telecommunication purposes have already been demonstrated [5],[6],