Olesya Bondarenko

Electrically pumped sub-wavelength metallo-dielectric pedestal pillar lasers

Electrically driven subwavelength scale metallo-dielectric pedestal pillar lasers are designed and experimentally demonstrated. The metallo-dielectric cavity significantly enhances the quality factor (Q > 1500) of the wavelength and subwavelength scale lasers and the pedestal structure significantly reduces the threshold gain (< 400 cm(-1)) which can potentially enable laser operation at room temperature. We observed continuous wave lasing in 750 nm gain core radius laser at temperatures between 77 K and 140 K with a threshold current of 50 μA (at 77 K). We also observed lasing from a 355 nm gain core radius laser at temperatures between 77 K and 100 K.

Etch-free low loss silicon waveguides using hydrogen silsesquioxane oxidation masks

An etch-free fabrication technique for creating low loss silicon waveguides in the silicon-on-insulator material system is proposed and demonstrated. The approach consists of local oxidation of a silicon-on-insulator chip covered with a e-beam patterned hydrogen silsesquioxane mask. A single oxidation step converts hydrogen silsesquioxane to a glass-like compound and simultaneously defines the waveguides, bypassing the need for any wet or dry etching steps. The spectral response of ring resonators fabricated using this technique was used to characterize the waveguide losses. Intrinsic Q-factors as high as 1.57 × 10(6), corresponding to a waveguide loss of 0.35 dB/cm, were measured.

Subwavelength semiconductor lasers for dense chip-scale integration

Metal-clad subwavelength lasers have recently become excellent candidates for light sources in densely packed chip-scale photonic circuits. In this review, we summarize recent research efforts in the theory, design, fabrication, and characterization of such lasers. We detail advancements of both the metallo-dielectric and the coaxial type lasers: for the metallo-dielectric type, we discuss operation with both optical pumping and electrical pumping. For the coaxial type, we discuss operation with all spontaneous emission coupled into the lasing mode, as well as the smallest metal-clad lasers to date operating at room temperature. A formal treatment of the Purcell effect, the modification of the spontaneous emission rate by a subwavelength cavity, is then presented to assist in better understanding the quantum effects in these nanoscale semiconductor lasers. This formalism is developed for the transparent medium condition, using the emitter-field-reservoir model in the quantum theory of damping. We show its utility through the analysis and design of subwavelength lasers. Finally, we discuss future research directions toward high-efficiency nanolasers and potential applications, such as creating planar arrays of uncoupled lasers with emitter densities near the resolution limit.

Wafer bonded distributed feedback laser with sidewall modulated Bragg gratings

We demonstrate an optically pumped hybrid III-V/Si distributed feedback laser with a small footprint, using sidewall modulated Bragg gratings for optical feedback. Our approach provides high overlap between lasing mode and gain medium and may enable hybrid lasers with improved efficiency, reduced threshold, and minimal size. We fabricate the structure using plasma-assisted wafer bonding, followed by self-aligned lithography and etching. The latter allows us to avoid alignment errors. This approach is a promising avenue toward ultracompact, energy efficient, and scalable monolithically integrated photonic circuits.

Wafer Bonded Subwavelength Metallo-Dielectric Laser

Light sources that are compatible with the silicon photonics platform are the key elements needed for photonic integrated circuits on silicon. Here, we report optically pumped wafer bonded metallodielectric lasers, subwavelength in all three dimensions (250-nm gain core radius) operating at 77 K, as well as near-subwavelength (450-nm gain core radius) operating at room temperature.

Temperature effects in metal-clad semiconductor nanolasers

Abstract As the field of semiconductor nanolasers becomes mature in terms of both the miniaturization to the true sub-wavelength scale, and the realization of room temperature devices, the integrated treatment of multiple design aspects beyond pure electromagnetic consideration becomes necessary to further advance the field. In this review, we focus on one such design aspect: temperature effects in nanolasers. We summarize recent efforts in understanding the interplay of various temperature-dependent parameters, and study their effects on optical mode and emission characteristics. Building on this knowledge, nanolasers with improved thermal performance can be designed, and their performance evaluated. Although this review focuses on metal-clad semiconductor lasers because of their suitability for dense chip-scale integration, these thermal considerations also apply to the broader field of nanolasers.

Silicon nanophotonic devices for chip-scale optical communication applications [Invited]

This paper reviews recent work in the area of silicon photonic devices and circuits for monolithic and heterogeneous integration of circuits and systems on a chip. In this context, it presents fabrication results for producing low-loss silicon waveguides without etching. Resonators and add-drop distributed filters utilizing sidewall modulation fabricated in a single lithography and etching step are demonstrated. It also presents an optical pulse compressor that monolithically integrates self-phase modulation and anomalous dispersion compensation devices on a silicon chip. As an example of heterogeneous integration, we demonstrate vertical emitting metallo-dielectric nanolasers integrated onto a silicon platform. Future research directions toward large-scale photonic circuits and systems on a chip also are discussed.

Electrically pumped subwavelength metallo-dielectric laser with low threshold gain

An electrically pumped subwavelength metallo-dielectric laser with a low threshold gain is demonstrated. To achieve low threshold gain, we selectively etch InP electrical channel diameter. Lasing operation is observed for temperatures up to 180 K.

Nanophotonic devices and circuits

Advances in nanoscale fabrication techniques in dielectric and metallic material systems has opened up new opportunities in photonics and plasmonics for solving long standing problems in information systems and telecommunication systems. In this talk, we discuss some of the metamaterials and devices that recently have been demonstrated in our lab. These include metamaterials with space variant polarizability to realize on-chip, frequencyselective resonators and Bragg gratings, as well as metal-semiconductor-dielectric nanolasers.

Room temperature lasing from subwavelength metal-insulator-semiconductor structures

We report pulsed room temperature lasing from optically pumped subwavelength metal-insulator-semiconductor structures. The lasers consist of InGaAsP gain disks embedded in a SiO2/ aluminum bi-layer. Lasing at 1520nm from a 730nm gain core is demonstrated.