Second-order cascading as the origin of large third-order effects in single crystal core fibers

Dug Y. Kim, William E. Torruellas, Christian Bosshard, George I. Stegeman, Petar Vidakovik, Joseph Zyss, W. E. Moerner, R. Twieg, G. Bjorklund

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

One of the largest off-resonant nonlinear effects attributed to a third order nonlinear process has been reported in a DAN single crystal core fiber. Such fiber, designed for efficient second harmonic generation, showed large spectral broadening effects when femtosecond pulses around 625 nm were launched into it. Yamashita et al. compared the observed spectral broadening to that of a standard fused silica fiber and reported an intensity dependent refractive index 17000 times larger than that of fused silica. In this paper we identify the relevant physics of the large nonlinearities observed in the fibers. We have performed nonlinear interferometry measurements on a similar DAN fiber at 1.320 μm, obtaining a comparable magnitude, n2 = -0.8 × 10-3 cm2/GW, with a surprising negative sign. Furthermore, by a modification of the fiber cladding refractive index, it was possible to make second harmonic generation either allowed or forbidden. In our case, a nonlinear phase shift was only present when a second harmonic was also observed. In order to verify a relation between the large nonlinearity and the presence of the second harmonic generation, we performed z-scan measurements on DAN single crystals at 1064 nm. These results, in magnitude and sign, compared favorably with our interferometric measurements at 1319 nm.

Original languageEnglish
Title of host publicationProceedings of the International Quantum Electronics Conference (IQEC'94)
PublisherPubl by IEEE
Pages16-17
Number of pages2
ISBN (Print)0780319737
Publication statusPublished - 1994 Dec 1
EventProceedings of the 21st International Quantum Electronics Conference (IQEC'94) - Anaheim, CA, USA
Duration: 1994 May 81994 May 13

Publication series

NameProceedings of the International Quantum Electronics Conference (IQEC'94)

Other

OtherProceedings of the 21st International Quantum Electronics Conference (IQEC'94)
CityAnaheim, CA, USA
Period94/5/894/5/13

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All Science Journal Classification (ASJC) codes

  • Engineering(all)

Cite this

Kim, D. Y., Torruellas, W. E., Bosshard, C., Stegeman, G. I., Vidakovik, P., Zyss, J., Moerner, W. E., Twieg, R., & Bjorklund, G. (1994). Second-order cascading as the origin of large third-order effects in single crystal core fibers. In Proceedings of the International Quantum Electronics Conference (IQEC'94) (pp. 16-17). (Proceedings of the International Quantum Electronics Conference (IQEC'94)). Publ by IEEE.