B. Ben Bakir

Electrically driven hybrid Si/III-V Fabry-Pérot lasers based on adiabatic mode transformers.

We report the first Si/III-V Fabry-Perot laser based on adiabatic mode transformers. The investigated device operates under quasi-continuous wave regime. The room temperature threshold current is 100 mA, the side mode suppression ratio is as high as 20dB, and the fiber-coupled output power is ∼7mW.

Amorphous silicon nanowires combining high nonlinearity, FOM and optical stability

We demonstrate optically stable amorphous silicon nanowires with both high nonlinear figure of merit (FOM) of ~5 and high nonlinearity Re(γ) = 1200W(-1)m(-1). We observe no degradation in these parameters over the entire course of our experiments including systematic study under operation at 2 W coupled peak power (i.e. ~2GW/cm(2)) over timescales of at least an hour.We demonstrate optically stable amorphous silicon nanowires with both high nonlinear figure of merit (FOM) of ~5 and high nonlinearity Re(γ) = 1200W -1 m -1 . We observe no degradation in these parameters over the entire course of our experiments including systematic study under operation at 2 W coupled peak power (i.e. ~2GW/cm 2 ) over timescales of at least an hour. References and links 1. J. Leuthold, C. Koos, and W. Freude, “Nonlinear silicon photonics,” Nat. Photonics 4, 535-544 (2010). 2. M. Foster, A. C. Turner, J. E. Sharping, B. S. Schmidt, M. Lipson, and A. L. 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Viktorovitch, “CMOS-compatible ultra-compact 1.55m emitting VCSELs using double photonic crystal mirrors,” IEEE Photon. Technol. Lett. 24, 455 (2012). 29. R. Orobtchouk, S. Jeannot, B. Han, T. Benyattou, J. M. Fedeli, and P. Mur, “Ultra compact optical link made in amorphous silicon waveguide,” Proc. SPIE 6183, conf. on Integrated Optics, Silicon Photonics, and Photonic Integrated Circuits, Strasbourg, paper 618304 (2006). 30. K.-Y. Wang, K. G. Petrillo, M. A. Foster, and A. C. Foster, “Ultralow-power 160-Gb/s all-optical demultiplexing in hydrogenated amorphous silicon waveguides,” in Integrated Photonics Research, Silicon and Nanophotonics, OSA Technical Digest (online), paper IW4C.3 (2012). 31. J. M. Fedeli, M. Migette, L. Di Cioccio, L. El Melhaoui, R. Orobtchouk, C. Seassal, P. Rojo-Romeo, F. Mandorlo, D. Marris-Morini, L. 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Broadband and compact 2-D photonic crystal reflectors with controllable polarization dependence

Two-dimensional (2-D) compact photonic crystal reflectors on suspended InP membranes were studied under normal incidence. We report the first experimental demonstration of 2-D broadband reflectors (experimental stopband superior to 200 nm, theoretical stopband of 350 nm). They are based on the coupling of free space waves with two slow Bloch modes of the crystal. Moreover, they present a very strong sensitivity of the polarization dependence, when modifying their geometry. A compact (50/spl times/50 /spl mu/m/sup 2/) demonstrator was realized and characterized, behaving either as a broadband reflector or as a broadband transmitter, depending on the polarization of the incident wave. Experimental results are in good agreement with numerical simulations.

Low-Loss (

We present a silicon-on-insulator (SOI) polarization-insensitive fiber-to-fiber coupler fabricated on a 200-mm wafer with the standard complementary metal-oxide-semiconductor technology. The coupling losses from a lensed fiber into a 500-nm-wide SOI waveguide were measured to be less than 1 dB in the 1520- to 1600-nm spectral range and below 3 dB between 1300 and 1600 nm.

1 dB) and Polarization-Insensitive Edge Fiber Couplers Fabricated on 200-mm Silicon-on-Insulator Wafers

We report on the design and fabrication of heterogeneous and compact surface-emitting microlasers, optically pumped and operating at 1.5μm at room-temperature. A very low threshold, below 15μW, is achieved. The devices consists of a top two-dimensional InP photonic crystal slab, including four InAsP quantum wells, a SiO2 bonding layer, and a bottom high index contrast Si∕SiO2 Bragg mirror deposited on a Si wafer. The graphitelike photonic crystal lattice is tailored for vertical emission. We theoretically and experimentally demonstrate that the Bragg reflector can strongly enhance the quality factor of the photonic crystal resonant mode, leading to a drastic decrease of the lasing threshold.

Surface-emitting microlaser combining two-dimensional photonic crystal membrane and vertical Bragg mirror

The authors report a compact and highly selective tunable filter using a Fabry-Perot resonator combining a bottom micromachined 3-pair-InP/air-gap Bragg reflector with a top photonic crystal slab mirror. It is based on the coupling between radiated vertical cavity modes and waveguided modes of the photonic crystal. The full-width at half maximum (FWHM) of the resonance, as measured by microreflectivity experiments, is close to 1.5nm (around 1.55 microm). The presence of the photonic crystal slab mirror results in a very compact resonator, with a limited number of layers. The demonstrator was tuned over a 20nm range for a 4V tuning voltage, the FWHM being kept below 2.5nm. Bending of membranes is a critical issue, and better results (FWHM=0.5nm) should be obtained on the same structure if this technological point is fixed.

Highly selective and compact tunable MOEMS photonic crystal Fabry-Perot filter

We demonstrate experimentally all-optical bistable operation in an InP-based two-dimensional photonic crystal slab lying on top of a Bragg reflector. Bistability is obtained around 1550nm, using a low group velocity mode at the band edge of the photonic dispersion characteristic. The origin of the bistable regime is shown to be the fast (275ps relaxation time), electronically induced nonlinear refraction index. A low intensity threshold of 4kW∕cm2 was observed, with a contrast of 65% between the high and low reflectivity states.

All-optical bistable band-edge Bloch modes in a two-dimensional photonic crystal

Long-wavelength vertical-cavity surface-emitting lasers (VCSELs) for photonics-on-complementary metal-oxide-semiconductor (CMOS) integration based on a double set of Si/SiO2 photonic crystal mirrors (PCMs) have been recently fabricated. In the present communication, an extensive overview about modal, polarization, and thermal features of optically pumped demonstrators is presented. Capable of operating continuous-wave up to 43°C at low thresholds, such VCSELs show single-mode polarization-stable operation at 1.55-μm with uncooled output powers in excess of 0.4 mW. This paper aims at singling out notably the device optical features arising from the excellent flexibility of the photonic architecture used. Noticeably, the light molding obtained through the engineering of Si/SiO2 photonic crystals allows for a tailored modal selection and full polarization control. Furthermore, the high-throughput cost-effective Si-based process technology developed is ideally well-suited for perspective industrial development.

Thermal, Modal, and Polarization Features of Double Photonic Crystal Vertical-Cavity Surface-Emitting Lasers

For about ten years, we have been developing InP on Si devices under different projects focusing first on μlasers then on semicompact lasers. For aiming the integration on a CMOS circuit and for thermal issue, we relied on SiO2 direct bonding of InP unpatterned materials. After the chemical removal of the InP substrate, the heterostructures lie on top of silicon waveguides of an SOI wafer with a separation of about 100nm. Different lasers or photodetectors have been achieved for off-chip optical communication and for intra-chip optical communication within an optical network. For high performance computing with high speed communication between cores, we developed InP microdisk lasers that are coupled to silicon waveguide and produced 100μW of optical power and that can be directly modulated up to 5G at different wavelengths. The optical network is based on wavelength selective circuits with ring resonators. InGaAs photodetectors are evanescently coupled to the silicon waveguide with an efficiency of 0.8A/W. The fabrication has been demonstrated at 200mm wafer scale in a microelectronics clean room for CMOS compatibility. For off-chip communication, silicon on InP evanescent laser have been realized with an innovative design where the cavity is defined in silicon and the gain localized in the QW of bonded InP hererostructure. The investigated devices operate at continuous wave regime with room temperature threshold current below 100 mA, the side mode suppression ratio is as high as 20dB, and the fibercoupled output power is ~7mW. Direct modulation can be achieved with already 6G operation.

InP on SOI devices for optical communication and optical network on chip

We report the first Silicon/III-V evanescent laser based on adiabatic mode transformers. The hybrid structure is formed by two vertically superimposed waveguides separated by a 100nm-thick SiO2 layer. The top waveguide, fabricated in an InP/InGaAsP-based heterostructure, serves to provide optical gain, and the bottom Si-waveguides system, which supports all optical functions, is constituted by two tapered rib-waveguides (mode transformers), two distributed Bragg reflectors (DBR), and a surface-grating coupler. The supermode of this hybrid structure is controlled by an appropriate design of the tapers located at the edges of the gain region. In the middle part of the devices, almost all the field resides in the III-V waveguide so that the optical mode experiences maximal gain, while in regions near the III-V facets, mode transformers ensure an efficient transfer of the power flow towards Si-waveguides. The investigated device operates under quasi-continuous wave regime. The room temperature threshold current is 100 mA, the side mode suppression ratio is as high as 20dB, and the fiber-coupled output power is ~7mW.