We demonstrate a highly polarized single mode nanobelt laser with a low threshold. Different from the traditional nanobelt lasers, the laser cavity is formed along the lateral direction of the nanobelt and the wavelength is centered at 712.6 nm with a linewidth of about 0.18 nm. The single mode lasing emission is highly polarized with a polarization ratio of about 0.91. Moreover, the threshold is as low as 18 μJ/cm2 which is about an order of magnitude lower than that of the traditional CdSe nanobelt lasers. These low threshold high polarization single mode nanobelt lasers offer great potential as a low cost and energy efficient choice of technology for applications in visible light communications, displays, optical sensing, and environmental monitoring.

Abstract-Optical interconnects require efficient and flexible optical sources. This paper presents results on two technology platforms being developed for realizing these. Integration using wafer bonding technologies is well established now and the focus is on new device types including tunable lasers, multi-wavelength lasers and switching. As an alternative, we also started work on monolithic integration using heteroepitaxy directly on silicon. We here report recent results on low threshold nanowire lasers.Index Terms-III-V on silicon, hetero-epitaxy, wafer bonding, integratd optics, silicon photonics.

The saturable absorption of a double-layer graphene modulator is experimentally demonstrated on a silicon slot waveguide platform. Saturation was found to start at ~0.8W with a maximum saturation depth of 1.9 dB for a 50 pm long graphene modulator.

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Abstract:In this work we present the design, simulation and characterization of a frequency down-converter based on III-V-on-silicon photonic integrated circuit technology. We first demonstrate the concept using commercial discrete components, after which we turn to the use of photonic integrated devices. In the demonstrations five channels in the Ka-band (27.5 GHz to 30 GHz) with 500 MHz bandwidth are down-converted to the L-band (1.5 GHz). The breadboard demonstration shows a conversion efficiency of -20 dB and a flat response over the 500 MHz bandwidth. The simulation of a fully integrated circuit indicates that a conversion gain can be obtained on a millimeter-sized photonic integrated circuit. AbstractIn this work we present the design, simulation and characterization of a frequency down-converter based on III-V-on-silicon photonic integrated circuit technology. We first demonstrate the concept using commercial discrete components, after which we turn to the use of photonic integrated devices. In the demonstrations five channels in the Ka-band (27.5 GHz to 30 GHz) with 500 MHz bandwidth are downconverted to the L-band (1.5 GHz). The breadboard demonstration shows a conversion efficiency of -20 dB and a flat response over the 500 MHz bandwidth. The simulation of a fully integrated circuit indicates that a conversion gain can be obtained on a millimeter-sized photonic integrated circuit.