Hannover 2010 – scientific programme

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Q: Fachverband Quantenoptik und Photonik

Q 54: Laser Applications: Optical Measurement Technology I

Q 54.5: Talk

Thursday, March 11, 2010, 15:00–15:15, F 342

Measurement of complex optical third-order nonlinearities in waveguides and bulk samples — •Anatoly Sherman, Erik Benkler, and Harald R. Telle — Physikalisch-Technische Bundesanstalt (PTB), Braunschweig, Germany

We demonstrate a novel method for measuring real and imaginary parts of the third-order nonlinear optical susceptibility (χ(3)) in waveguides and bulk samples. Here, the unknown nonlinearity of the device under test is compared, under nearly identical experimental circumstances, with the known value of a reference sample. In order to gain information about both amplitude and phase of χ(3), a four-wave mixing set-up is combined with a phase-sensitive heterodyne detection scheme. The overall phase is calibrated during such measurements using reference sample with negligible two-photon absorption (i. e. fused silica at telecommunication wavelength). From the ratio of both quadrature components of χ(3), one directly deduces the so-called nonlinear figure of merit, which is an important parameter of all-optical circuits. As a source of error, spurious mixing signals generated from the photodiode are eliminated by all-optical methods.