Y. A. Vlasov

Engineering nonlinearities in nanoscale optical systems: physics and applications in dispersion-engineered silicon nanophotonic wires

The nonlinear optics of Si photonic wires is discussed. The distinctive features of these waveguides are that they have extremely large third-order susceptibility χ(3) and dispersive properties. The strong dispersion and large third-order nonlinearity in Si photonic wires cause the linear and nonlinear optical physics in these guides to be intimately linked. By carefully choosing the waveguide dimensions, both linear and nonlinear optical properties of Si wires can be engineered. We review the fundamental optical physics and emerging applications for these Si wires. In many cases, the relatively low threshold powers for nonlinear optical effects in these wires make them potential candidates for functional on-chip nonlinear optical devices of just a few millimeters in length; conversely, the absence of nonlinear optical impairment is important for the use of Si wires in on-chip interconnects. In addition, the characteristic length scales of linear and nonlinear optical effects in Si wires are markedly different from those in commonly used optical guiding systems, such as optical fibers or photonic crystal fibers, and therefore guiding structures based on Si wires represent ideal optical media for investigating new and intriguing physical phenomena.

Nonlinear-optical phase modification in dispersion-engineered Si photonic wires

The strong dispersion and large third-order nonlinearity in Si photonic wires are intimately linked in the optical physics needed for the optical control of phase. By carefully choosing the waveguide dimensions, both linear and nonlinear optical properties of Si wires can be engineered. In this paper we provide a review of the control of phase using nonlinear-optical effects such as self-phase and cross-phase modulation in dispersion-engineered Si wires. The low threshold powers for phase-changing effects in Si-wires make them potential candidates for functional nonlinear optical devices of just a few millimeters in length.

A 25 Gbps silicon microring modulator based on an interleaved junction.

A silicon microring modulator utilizing an interleaved p-n junction phase shifter with a V(π)L of 0.76 V-cm and a minimum off-resonance insertion loss of less than 0.2 dB is demonstrated. The modulator operates at 25 Gbps at a drive voltage of 1.6 V and 2-3 dB excess optical insertion loss, conditions which correspond to a power consumption of 471 fJ/bit. Eye diagrams are characterized at up to 40 Gbps, and transmission is demonstrated across more than 10 km of single-mode fiber with minimal signal degradation.

Silicon nanowire active integrated optics

We employ ultranarrow silicon-on-insulator (SOI) waveguides to demonstrate significant Raman gain using low CW pump powers from a diode laser. Starting with measurements based on spontaneous Raman scattering in nanowire SOI waveguides, we obtain the parameters necessary to develop a useful numerical modeling tool for our system. This work shows clearly the feasibility of an SOI-based low-loss, low-power, on-chip Raman amplifier in the silicon nanowire system. We have also developed a rigorous coupled wave model to examine temporal effects in our Raman system.

A figure of merit based transmitter link penalty calculation for plasma-dispersion electro-optic Mach-Zehnder modulators

We present equations that quantify CMOS Mach-Zehnder Interferometer (MZI) modulator impact on non return to zero (NRZ) optical link budget based on modulator extinction ratio (ER), the efficiency-loss figure of merit (FOM), and attainable peak-to-peak drive voltage (Vpp). Our modulator link penalty equations transform modulator FOM into a means of predicting how design and technology choices impact system margin.

Cross-phase modulation in silicon photonic wire waveguides

We demonstrate strong cross-phase modulation in Si photonic wire waveguides using picosecond pulses. We present an all-optical scheme for control of optical pulses, utilizing the tight optical confinement of wire waveguides to enhance the nonlinearity.