Opto mechanics of standard fibers: Sensing crosstalk and oscillations

by Avi Zadok

at Quantum optics seminar

Thu, 11 May 2017, 15:30
Physics building (#54) room 207

Abstract

We all know that optical fibers guide light Much less attention is drawn to the fact that optical fibers also support guided sound waves The propagation of light in the fiber may stimulate the oscillations of these acoustic modes The sound waves in turn may scatter light waves and couple power between optical fields Although the phenomenon is known since the 1980 s it has found little role in fiber optics technology to date Guided acoustic modes of optical fibers do give us however a property that guided light cannot: the transverse profiles of guided sound waves are not confined to the inner core Instead they spread across the entire cladding cross section and reach the outer cladding boundary Our group has been investigating the coupling between light and sound in fibers over the last two years In this talk I will present several implications of such coupling which might appear surprising at first On top of their fundamental interest the results are of practical significance in the contexts of fiber sensors telecommunication and microwave photonics: 1 Acoustic wave scattering allows us to take measurements of substances outside the cladding boundary of a standard unmodified fiber where light does not reach We are therefore able to listen where we cannot look The mechanical impedance of surrounding media is measured with 1 accuracy The protocol has been recently extended to distributed analysis 2 Acoustic wave scattering induces cross talk among the different cores of multi core fibers even when the direct coupling of optical power is entirely negligible 3 Lastly guided acoustic waves scattering can lead to opto electro mechanic oscillations at radio frequencies in standard fiber

Created on 05-05-2017 by Bar Lev, Yevgeny (ybarlev)
Updaded on 05-05-2017 by Bar Lev, Yevgeny (ybarlev)