Chip-scale photonics
The goal of our research is to advance the fundamental understanding and technological methods for realizing complex photonic circuits consisting of dozens or hundreds of micro-resonator or interferometric devices on a single chip, and to push the functionality of chip-scale devices for nonlinear and/or quantum applications closer to the ultimate limits of what can be achieved.
We are studying silicon multi-ring resonator circuits [Opt Lett 2010] and have demonstrated record-length (235 rings) coupled-resonator optical waveguides in silicon [Opt Lett 2010]. Such waveguides have been used to enhance the efficiency of four-wave mixing by +16 dB relative to a conventional silicon nanophotonic waveguide [Opt Lett 2011] and to demonstrate telecommunications-band heralded single photons from a CMOS-compatible silicon nanophotonic chip [arXiv].
Using silicon nanophotonic structures, we have designed and demonstrated "giant" birefringence (Δn∼2) in multi-slotted waveguides [Opt Express 2009]. Silicon waveguides can also be used as a compact source of longer wavelength (>2.2 μm) infrared light via four-wave mixing in conjunction with fiber-optical seed sources [Nat Photon 2010].
Nanoscale disorder has a large impact on the performance of in high-index contrast silicon-on-insulator (SOI) photonic resonators, and in particular, on slow wave structures [Opt Lett 2007]. We reported that disorder-induced localization of light in compact SOI CROWs leads to spatially concentrated and locally trapped light in a quasi-one-dimensional waveguide at wavelengths near the band edge [Nat Photon 2008]. Recently, we have demonstrated favorable statistical intensity and group delay distributions of extremely long microring CROWs (coupled-resonator optical waveguides) [Opt Express 2010] and investigated how many hundreds of silicon microrings can be coupled before disorder-induced bandwidth collapse occurs [Opt Lett, 2011]. At the OFC 2011 post-deadline session, we reported a set-and-forget method for tuning silicon nanophotonic microrings and Mach-Zehnder interferometers, achieving 0.002 nm (0.2 GHz) precision in aligning resonances, and zero power consumption after modification to "hold" the tuned state [OFC-PDPC3].
Selected publications
- J. Ong, M. L. Cooper, G. Gupta, W. M. J. Green, S. Assefa, F. Xia, and S. Mookherjea "Low power continuous-wave four-wave mixing in silicon coupled-resonator optical waveguides", Optics Letters, Vol. 36, No. 15, pp. 2964-2966 (2011). [URL]
- M. L. Cooper, G. Gupta, M. A. Schneider, W. M. J. Green, S. Assefa, F. Xia, Y. A. Vlasov, and S. Mookherjea, "Statistics of light transport in 235-ring silicon coupled-resonator optical waveguides" Optics Express Vol. 18, pp. 26505-26516 (2010). [URL]
- S. Zlatanovic, J. S. Park, S. Moro, J. M. Chavez-Boggio, I. B. Divliansky, N. Alic, S. Mookherjea, S. Radic, "Mid-Infrared Wavelength Conversion in Silicon Waveguides using Ultracompact Telecom-Band-Derived Pump Source" Nature Photonics, Vol. 4, 561-564 (2010). [URL]
- S. Mookherjea, J. S. Park, S. H. Yang and P. R. Bandaru, "Localization in silicon nanophotonic slow-light waveguides", Nature Photonics, Vol. 2, No. 2, pp. 90-93 (2008). [DOI] [PDF]