Welcome to the new version of CaltechAUTHORS. Login is currently restricted to library staff. If you notice any issues, please email coda@library.caltech.edu
Published September 2008 | Published
Journal Article Open

All-Optical Modulation in a Silicon Waveguide Based on a Single-Photon Process


All-optical, low-power modulation is a major goal in photonics. Because of their high mode-field concentration and ease of manufacturing, nanoscale silicon waveguides offer an intriguing platform for photonics. So far, all-optical modulators built with silicon photonic circuits have relied on either two-photon absorption or the Kerr effect. Both effects are weak in silicon, and require extremely high (~5 W) peak optical power levels to achieve modulation. Here, we describe an all-optical Mach-Zehnder modulator based on a single-photon absorption (SPA) process, fabricated entirely in silicon. Our SPA modulator is based on a process by which a single photon at 1.55 mum is absorbed and an apparently free-carrier-mediated process causes an index shift in silicon, even though the photon energy does not exceed that of silicon's bandgap. We demonstrate all-optical modulation with a gate response of 1deg/mW at 0.5 Gb/s. This is over an order of magnitude more responsive than typical previously demonstrated devices. Even without resonant enhancement, further engineering may enable all optical modulation with less than 10 mW of gate power required for complete extinction, and speeds of 5 Gb/s or higher.

Additional Information

© 2008 IEEE. Reprinted with permission. Manuscript received January 8, 2008. Current version published October 3, 2008. [Current Version Published: 2008-09-30] This work was supported in part by the National Science Foundation in part by the Defense Advanced Research Projects Agency (DARPA) under the Electronic and Photonic Integrated Circuits (EPIC) Program HR-04-1-0054, and in part by the Air Force Office of Scientific Research Young Investigator Program under Grant FA9550-08-0101. The authors acknowledge J. Huang, B. Penkov, and A. Homyk for assistance with the measurements and imaging. They also acknowledge Prof. S. Dunham for a number of useful discussions. Device fabrication was performed at the Cornell Nanoscale Facility.

Attached Files

Published - BAEieeejstqe08.pdf


Files (1.7 MB)
Name Size Download all
1.7 MB Preview Download

Additional details

August 22, 2023
March 5, 2024