Lidija Sekaric

Bio: Lidija Sekaric is an academic researcher from IBM. The author has contributed to research in topics: Nanowire & Silicon. The author has an hindex of 29, co-authored 80 publications receiving 5941 citations. Previous affiliations of Lidija Sekaric include Cornell University & GlobalFoundries.

Ultracompact optical buffers on a silicon chip

Abstract: On-chip optical buffers based on waveguide delay lines might have significant implications for the development of optical interconnects in computer systems. Silicon-on-insulator (SOI) submicrometre photonic wire waveguides are used, because they can provide strong light confinement at the diffraction limit, allowing dramatic scaling of device size. Here we report on-chip optical delay lines based on such waveguides that consist of up to 100 microring resonators cascaded in either coupled-resonator or all-pass filter (APF) configurations. On-chip group delays exceeding 500 ps are demonstrated in a device with a footprint below 0.09 mm2. The trade-offs between resonantly enhanced group delay, device size, insertion loss and operational bandwidth are analysed for various delay-line designs. A large fractional group delay exceeding 10 bits is achieved for bit rates as high as 20 Gbps. Measurements of system-level metrics as bit error rates for different bit rates demonstrate error-free operation up to 5 Gbps.

Ultra-compact, low RF power, 10 Gb/s silicon Mach-Zehnder modulator.

Abstract: Silicon p(+)-i-n(+) diode Mach-Zehnder electrooptic modulators having an ultra-compact length of 100 to 200 mum are presented. These devices exhibit high modulation efficiency, with a V(pi)L figure of merit of 0.36 V-mm. Optical modulation at data rates up to 10 Gb/s is demonstrated with low RF power consumption of only 5 pJ/bit.

Stable SRAM cell design for the 32 nm node and beyond

Abstract: SRAM cell stability will be a primary concern for future technologies due to variability and decreasing power supply voltages. 6T-SRAM can be optimized for stability by choosing the cell layout, device threshold voltages, and the /spl beta/ ratio. 8T-SRAM, however, provides a much greater enhancement in stability by eliminating cell disturbs during a read access, thus facilitating continued technology scaling. We demonstrate the smallest 6T (0.124/spl mu/m/sup 2/ half-cell) and full 8T (0.1998/spl mu/m/sup 2/) cells to date.

Ultra-compact high order ring resonator filters using submicron silicon photonic wires for on-chip optical interconnects

Abstract: Ultra-compact 5(th) order ring resonator optical filters based on submicron silicon photonic wires are demonstrated. Out-of-band rejection ratio of 40dB, 1dB flat-top pass band of 310GHz with ripples smaller than 0.4dB, and insertion loss of only (1.8+/-0.5)dB at the center of the pass band are realized simultaneously, all within a footprint of 0.0007mm(2) on a silicon chip.

Measurement of mechanical resonance and losses in nanometer scale silicon wires

Abstract: We present data on nanofabricated suspended silicon wires driven at resonance. The wires are electrostatically driven and detected optically. We have observed wires with widths as small as 45 nm and resonant frequencies as high as 380 MHz. We see a strong dependence of the resonant quality factor on the surface to volume ratio.

Cavity Optomechanics

Abstract: We review the field of cavity optomechanics, which explores the interaction between electromagnetic radiation and nano- or micromechanical motion This review covers the basics of optical cavities and mechanical resonators, their mutual optomechanical interaction mediated by the radiation pressure force, the large variety of experimental systems which exhibit this interaction, optical measurements of mechanical motion, dynamical backaction amplification and cooling, nonlinear dynamics, multimode optomechanics, and proposals for future cavity quantum optomechanics experiments In addition, we describe the perspectives for fundamental quantum physics and for possible applications of optomechanical devices

Electromechanical Resonators from Graphene Sheets

Abstract: Nanoelectromechanical systems were fabricated from single- and multilayer graphene sheets by mechanically exfoliating thin sheets from graphite over trenches in silicon oxide. Vibrations with fundamental resonant frequencies in the megahertz range are actuated either optically or electrically and detected optically by interferometry. We demonstrate room-temperature charge sensitivities down to 8 × 10 –4 electrons per root hertz. The thinnest resonator consists of a single suspended layer of atoms and represents the ultimate limit of two-dimensional nanoelectromechanical systems.

Silicon optical modulators

Abstract: Optical technology is poised to revolutionize short-reach interconnects. The leading candidate technology is silicon photonics, and the workhorse of such an interconnect is the optical modulator. Modulators have been improved dramatically in recent years, with a notable increase in bandwidth from the megahertz to the multigigahertz regime in just over half a decade. However, the demands of optical interconnects are significant, and many questions remain unanswered as to whether silicon can meet the required performance metrics. Minimizing metrics such as the device footprint and energy requirement per bit, while also maximizing bandwidth and modulation depth, is non-trivial. All of this must be achieved within an acceptable thermal tolerance and optical spectral width using CMOS-compatible fabrication processes. This Review discusses the techniques that have been (and will continue to be) used to implement silicon optical modulators, as well as providing an outlook for these devices and the candidate solutions of the future.

Silicon microring resonators

Abstract: An overview is presented of the current state-of-the-art in silicon nanophotonic ring resonators. Basic theory of ring resonators is discussed, and applied to the peculiarities of submicron silicon photonic wire waveguides: the small dimensions and tight bend radii, sensitivity to perturbations and the boundary conditions of the fabrication processes. Theory is compared to quantitative measurements. Finally, several of the more promising applications of silicon ring resonators are discussed: filters and optical delay lines, label-free biosensors, and active rings for efficient modulators and even light sources.

Device Requirements for Optical Interconnects to Silicon Chips

Abstract: We examine the current performance and future demands of interconnects to and on silicon chips. We compare electrical and optical interconnects and project the requirements for optoelectronic and optical devices if optics is to solve the major problems of interconnects for future high-performance silicon chips. Optics has potential benefits in interconnect density, energy, and timing. The necessity of low interconnect energy imposes low limits especially on the energy of the optical output devices, with a ~ 10 fJ/bit device energy target emerging. Some optical modulators and radical laser approaches may meet this requirement. Low (e.g., a few femtofarads or less) photodetector capacitance is important. Very compact wavelength splitters are essential for connecting the information to fibers. Dense waveguides are necessary on-chip or on boards for guided wave optical approaches, especially if very high clock rates or dense wavelength-division multiplexing (WDM) is to be avoided. Free-space optics potentially can handle the necessary bandwidths even without fast clocks or WDM. With such technology, however, optics may enable the continued scaling of interconnect capacity required by future chips.