Publications

2016
Yoshitomo, Okawachi, Mengjie Yu, Kevin Luke, Daniel O. Carvalho, Michal Lipson, and Alexander L. Gaeta. “Quantum random number generator using a microresonator-based Kerr oscillator.” Opt. Lett. 41 (2016): 4194–4197. Publisher's Version Abstract
We demonstrate an all-optical quantum random number generator using a dual-pumped degenerate optical parametric oscillator in a silicon nitride microresonator. The frequency-degenerate bi-phase state output is realized using parametric four-wave mixing in the normal group-velocity dispersion regime with two nondegenerate pumps. We achieve a random number generation rate of 2 MHz and verify the randomness of our output using the National Institute of Standards and Technology Statistical Test Suite. The scheme offers potential for a chip-scale random number generator with gigahertz generation rates and no postprocessing.
ol-41-18-4194.pdf
2015
Okawachi, Yoshitomo, Mengjie Yu, Kevin Luke, Daniel O. Carvalho, Sven Ramelow, Alessandro Farsi, Michal Lipson, and Alexander L. Gaeta. “Dual-pumped degenerate Kerr oscillator in a silicon nitride microresonator.” Opt. Lett. 40 (2015): 5267–5270. Publisher's Version Abstract
We demonstrate a degenerate parametric oscillator in a silicon nitride microresonator. We use two frequency-detuned pump waves to perform parametric four-wave mixing and operate in the normal group-velocity dispersion regime to produce signal and idler fields that are frequency degenerate. Our theoretical modeling shows that this regime enables generation of bimodal phase states, analogous to the chi(2)-based degenerate OPO. Our system offers potential for realization of CMOS-chip-based coherent optical computing and an all-optical quantum random number generator.
okawachi_dual_pumped_kerr.pdf
2014
Okawachi, Yoshitomo, Michael R. E. Lamont, Kevin Luke, Daniel O. Carvalho, Mengjie Yu, Michal Lipson, and Alexander L. Gaeta. “Bandwidth shaping of microresonator-based frequency combs via dispersion engineering.” Optics Letters 39 (2014): 3535-3538. Publisher's Version Abstract
We investigate experimentally and theoretically the role of group-velocity dispersion and higher-order dispersion on the bandwidth of microresonator-based parametric frequency combs. We show that the comb bandwidth and the power contained in the comb can be tailored for a particular application. Additionally, our results demonstrate that fourth-order dispersion plays a critical role in determining the spectral bandwidth for comb bandwidths on the order of an octave. (C) 2014 Optical Society of America
okawachi_bw_shaping_combs_ol_2014.pdf