Abstract
We study the use of nonlinear self-phase modulation (SPM) in coupled optical microresonators for ultrasensitive refractive index sensing. SPM leads to a positive feedback enhancement of the resonance frequency shift caused by a perturbation of the index of refraction in a resonator. Moreover, the use of two resonators coupled through input and output waveguides leads to a further improvement in the sensitivity owing to constructive interference and feedback via the waveguides. For parameters based on Si microresonators, the sensitivity is more than larger than a single resonator without SPM leading to a minimum detectable index change of with resonator -factors of . We show that the nonlinearly enhanced system is robust with respect to laser noise when operated at input powers below the onset of bistability.
© 2013 Optical Society of America
Full Article | PDF ArticleMore Like This
A. Giorgini, S. Avino, P. Malara, G. Gagliardi, M. Casalino, G. Coppola, M. Iodice, P. Adam, K. Chadt, J. Homola, and P. De Natale
Opt. Lett. 38(11) 1951-1953 (2013)
Chao Wang and Christopher P. Search
Opt. Lett. 39(15) 4376-4379 (2014)
Chunyu Lu, Hamed Nikbakht, Mustafa Karabiyik, Musa Alaydrus, and B. Imran Akca
Opt. Express 29(25) 42215-42224 (2021)