Mid-infrared supercontinuum generation in silicon-germanium all-normal dispersion waveguides.

We demonstrate coherent supercontinuum generation spanning over an octave from a silicon germanium-on-silicon waveguide using ∼200 pulses at a wavelength of 4 µm. The waveguide is engineered to provide low all-normal dispersion in the TM polarization. We validate the coherence of the generated supercontinuum via simulations, with a high degree of coherence across the entire spectrum.

Sub-wavelength grating interdigitated combs as photonic waveguides.

In this Letter, we demonstrate a new, to the best of our knowledge, kind of photonic waveguide, in which the light propagates in the overlap of sub-wavelength patterned interdigitated combs. We present the fabrication and characterization of this waveguide, along with an adiabatic taper ensuring lossless transition with classical photonic waveguides. Finally, we explore some practical applications of this waveguide, as a bio-photonic sensor or as an optomechanical transduction scheme.

Integrated waveguide PIN photodiodes exploiting lateral Si/Ge/Si heterojunction.

Germanium photodetectors are considered to be mature components in the silicon photonics device library. They are critical for applications in sensing, communications, or optical interconnects. In this work, we report on design, fabrication, and experimental demonstration of an integrated waveguide PIN photodiode architecture that calls upon lateral double Silicon/Germanium/Silicon (Si/Ge/Si) heterojunctions.

Controlling leakage losses in subwavelength grating silicon metamaterial waveguides.

Subwavelength gratings (SWG) are photonic structures with a period small enough to suppress diffraction, thereby acting as artificial dielectric materials, also called all-dielectric metamaterials. This property has been exploited in many high-performance photonic integrated devices in the silicon-on-insulator (SOI) platform. While SWG waveguides are theoretically lossless, they may exhibit leakage penalty to the substrate due to a combination of reduced modal confinement and finite thickness of the buried oxide (BOX) layer.

High-directionality fiber-chip grating coupler with interleaved trenches and subwavelength index-matching structure.

We present the first experimental demonstration of a new fiber-chip grating coupler concept that exploits the blazing effect by interleaving the standard full (220 nm) and shallow etch (70 nm) trenches in a 220 nm thick silicon layer. The high directionality is obtained by controlling the separation between the deep and shallow trenches to achieve constructive interference in the upward direction and destructive interference toward the silicon substrate. Utilizing this concept, the grating directionality can be maximized independent of the bottom oxide thickness.

Compact models for carrier-injection silicon microring modulators.

We propose compact DC and small-signal models for carrier-injection microring modulators that accurately describe the DC characteristics (resonance wavelength, quality factor, and extinction ratio) and the high frequency performance. The proposed theoretical models provide physical insights of the carrier-injection microring modulators with a variety of designs. The DC and small-signal models are implemented in Verilog-A for SPICE-compatible simulations.

Germanium avalanche receiver for low power interconnects.

Recent advances in silicon photonics have aided the development of on-chip communications. Power consumption, however, remains an issue in almost all integrated devices. Here, we report a 10 Gbit per second waveguide avalanche germanium photodiode under low reverse bias.

Demonstration of a heterogeneously integrated III-V/SOI single wavelength tunable laser.

A heterogeneously integrated III-V-on-silicon laser is reported, integrating a III-V gain section, a silicon ring resonator for wavelength selection and two silicon Bragg grating reflectors as back and front mirrors. Single wavelength operation with a side mode suppression ratio higher than 45 dB is obtained. An output power up to 10 mW at 20 °C and a thermo-optic wavelength tuning range of 8 nm are achieved.

Interferometric switching in coupled resonator optical waveguides-based reconfigurable optical device.

Integrated optical devices based on coupled resonator optical waveguides (CROW) for reconfigurable band routing are explored. A reconfiguration principle based on two bus interferometric CROW resonant structures is proposed. This device extends the functionalities of simple add-drop filters, adding more switching features.

Broadband microwave photonic fully tunable filter using a single heterogeneously integrated III-V/SOI-microdisk-based phase shifter.

A broadband microwave photonic phase shifter based on a single III-V microdisk resonator heterogeneously integrated on and coupled to a nanophotonic silicon-on-insulator waveguide is reported. The phase shift tunability is accomplished by modifying the effective index through carrier injection. A comprehensive semi-analytical model aiming at predicting its behavior is formulated and confirmed by measurements.

40 Gbit/s low-loss silicon optical modulator based on a pipin diode.

40 Gbit/s low-loss silicon optical modulators are demonstrated. The devices are based on the carrier depletion effect in a pipin diode to generate a good compromise between high efficiency, speed and low optical loss. The diode is embedded in a Mach-Zehnder interferometer, and a self-aligned fabrication process was used to obtain precise localization of the active p-doped region in the middle of the waveguide.

Chip-to-chip optical interconnections between stacked self-aligned SOI photonic chips.

Photonic silicon devices are key enabling technologies for next generation High Performance Computers. In this paper, we report the possibility to stack and optically interconnect SOI based photonic chips for future System-In-Package photonic architecture. Combining vertical grating couplers and state-of-the-art flip-chip technology, we demonstrated low loss penalties and wide spectral range optical interconnections between stacked photonic chips.

Zero-bias 40Gbit/s germanium waveguide photodetector on silicon.

We report on lateral pin germanium photodetectors selectively grown at the end of silicon waveguides. A very high optical bandwidth, estimated up to 120GHz, was evidenced in 10 µm long Ge photodetectors using three kinds of experimental set-ups. In addition, a responsivity of 0.

10 Gbit/s all-optical NRZ-OOK to RZ-OOK format conversion in an ultra-small III-V-on-silicon microdisk fabricated in a CMOS pilot line.

We report the demonstration of an all-optical, bias free and error-free (bit-error-rate ~10(-12)), 10 Gbit/s non-return-to-zero (NRZ) to return-to-zero (RZ) data format conversion using a 7.5 µm diameter III-V-on-silicon microdisk resonator. The device is completely processed in a 200 mm CMOS pilot line.

Ten Gbit/s ring resonator silicon modulator based on interdigitated PN junctions.

10 Gbit/s silicon modulator based on carrier depletion in interdigitated PN junctions is experimentally demonstrated. The phase-shifter is integrated in a ring resonator, and high extinction ratio larger than 10 dB is obtained in both TE and TM polarizations. VπLπ of about 2.

Optical characterization of a SCISSOR device.

Here, we report on the design, fabrication and characterization of single-channel (SC-) and dual-channel (DC-) side-coupled integrated spaced sequences of optical resonators (SCISSOR) with a finite number (eight) of microring resonators using submicron silicon photonic wires on a silicon-on-insulator (SOI) wafer. We present results on the observation of multiple resonances in the through and the drop port signals of DC-SCISSOR. These result from the coupled resonator induced transparency (CRIT) which appears when the resonator band (RB) and the Bragg band (BB) are nearly coincident.

Ultrafast and bias-free all-optical wavelength conversion using III-V-on-silicon technology.

Using a 7.5 μm diameter disk fabricated with III-V-on-silicon fabrication technology, we demonstrate bias-free all-optical wavelength conversion for non-return-to-zero on-off keyed pseudorandom bit sequence (PRBS) data at the speed of 10 Gbits/s with an extinction ratio of more than 12 dB. The working principle of such a wavelength converter is based on free-carrier-induced refractive index modulation in a pump-probe configuration.

High extinction ratio 10 Gbit/s silicon optical modulator.

High speed and high extinction ratio silicon optical modulator using carrier depletion is experimentally demonstrated. The phase-shifter is a 1.8 mm-long PIPIN diode which is integrated in a Mach Zehnder interferometer.

Silicon-polymer hybrid slot waveguide ring-resonator modulator.

We demonstrate a ring-resonator modulator based on a silicon-polymer hybrid slot waveguide with a tunability of 12.7 pm/V at RF speeds and a bandwidth of 1 GHz, for optical wavelengths near 1550 nm. Our slot waveguides were fabricated with 193 nm optical lithography, as opposed to the electron beam lithography used for previous results.

Low-loss strip-loaded slot waveguides in silicon-on-insulator.

Electro-optic polymer-clad silicon slot waveguides have recently been used to build a new class of modulators, that exhibit very high bandwidths and extremely low drive voltages. A key step towards making these devices practical will be lowering optical insertion losses. We report on the first measurements of low-loss waveguides that are geometrically suitable for high bandwidth slot waveguide modulators: a strip-loaded slot waveguide.

Real-time cancellation of temperature induced resonance shifts in SOI wire waveguide ring resonator label-free biosensor arrays.

A comprehensive investigation of real-time temperature-induced resonance shift cancellation for silicon wire based biosensor arrays is reported for the first time. A reference resonator, protected by either a SU8 or SiO(2) cladding layer, is used to track temperature changes. The temperature dependence of resonators in aqueous solutions, pertinent to biosensing applications, is measured under steady-state conditions and the operating parameters influencing these properties are discussed.

Real-space observation of spectral degeneracy breaking in a waveguide-coupled disk microresonator.

We report on the real-space observation of resonant frequency splitting in a high-Q waveguide-coupled silicon-on-insulator microdisk resonator. Phase sensitive near-field analysis reveals the stationary nature of the two resonant states, and spectral investigations clearly show their orthogonality. These measurements emphasize the role of the coupling waveguide in this splitting phenomenon.

Efficient directional coupling between silicon and copper plasmonic nanoslot waveguides: toward metal-oxide-silicon nanophotonics.

Coupling plasmonics and silicon photonics is the best way to bridge the size gap between macroscopic optics and nanodevices in general and especially nanoelectronic devices. We report on the realization of key blocks for future plasmonic planar integrated optics, nano-optical couplers, and nanoslot waveguides that are compatible both with the silicon photonics and the CMOS microelectronics. Copper-based devices provide for very efficient optical coupling, unexpectedly low propagation losses and a broadband sub-50 nm optical confinement.

Ultrafast all-optical switching in a silicon-nanocrystal-based silicon slot waveguide at telecom wavelengths.

We demonstrate experimentally all-optical switching on a silicon chip at telecom wavelengths. The switching device comprises a compact ring resonator formed by horizontal silicon slot waveguides filled with highly nonlinear silicon nanocrystals in silica. When pumping at power levels about 100 mW using 10 ps pulses, more than 50% modulation depth is observed at the switch output.

NanoSi low loss horizontal slot waveguides coupled to high Q ring resonators.

Si-based horizontal slot waveguides coupled to ring resonators have been fabricated and characterised. The central layer of the slot has been filled by Silicon nanocrystals (Si-nc) obtained by deposition of silicon rich silicon oxide and then thermal annealing. A comparison of various deposition and annealing parameters to form the Si-nc is performed.