Researchers at the University of New Mexico in Albuquerque have fabricated quantum-dash lasers of InAs and InP that display pulsed output at 1.6 to 1.66 µm at room temperature. The devices feature threshold current densities as low as 410 A/cm2 and may find applications in long-haul telecommunications systems.The researchers, who reported their findings in the August issue of IEEE Photonics Technology Letters, employed solid-source molecular beam epitaxy to grow the 300-nm-long dashes on an N-type InP substrate in one-, three- and five-stack designs. The wavelength increased with the number of stacks, which they attribute to an increase in the size of the dashes as stacks are added.