Quantum-dot laser with a metal-coated waveguide under continuous-wave operation at room temperature

We fabricated and characterized Fabry-Perot quantum-dot lasers with metal-coated waveguides. Lasing action at room temperature under continuous-wave operation was observed, contrary to the belief that metal is too lossy to serve as the waveguide material at optical frequencies. We extracted the optical gain and group index from the amplified spontaneous emission spectra. A high group index of about 4.2 has been observed from these metal-coated devices, which is much larger than a value of 3.2 measured from an uncoated quantum-dot laser. It is believed that the metal coating contributes to the high group index in these devices. (C) 2009 American Institute of Physics. [doi: 10.1063/1.3272687]