Direct continuous-wave measurement of n2 in various types of telecommunication fiber at 155 μm

Abstract

A method for measuring the nonlinear refractive index of optical fibers with an error of less than 5% is demonstrated. The technique is based on measuring the nonlinear phase shift experienced by a dual-frequency beat signal, permitting a simple, highly sensitive, accurate, repeatable, and easily automated measurement procedure and sampling. Measurements of the nonlinear coefficient in standard telecommunication, dispersion-shifted, and a number of dispersion-compensated fibers are presented.

Generalised dispersive phase and its effect on four wave mixing in fibers

“…In CW SPM method, two DFB laser diodes with parallel polarization produce an optical beat signal which is propagated through a test fiber and the non-linear phase shift induced by the self phase modulation effect is measured while the dispersion is neglected [28]. The measurement result is hence independent of the frequency separation of the laser sources.…”

Dual-Wavelength Pumped Dispersion-Compensating Fibre Raman Amplifiers

“…Guided waves in optical fibres are subject to nonlinear optical interactions, such as selfphase modulation, cross-phase modulation and four-wave mixing, all of which increase the bit error rate. Normally the effects are not problematical in a few kilometres of fibre but DCFs have small core diameters and high germania-content glasses, both of which enhance the nonlinear optical processes (Boskovic et al, 1996). Moreover, the Raman gain maintains a higher signal power along the fibre, which is also detrimental in this respect.…”

Nonlinear Optics in Doped Silica Glass Integrated Waveguide Structures

“…By fitting experiments with simulations, a value of = 220 W -1 km -1 was determined, corresponding to a value of n 2 = 1.1 x 10 -19 m 2 /W (A = 2.0 μm 2 ). Similar experiments in single mode fibers (Agrawal, 2006;Boskovic et al, 1996), semiconductors (Siviloglou et al, 2006;Dulkeith et al, 2006), and chalcogenides (Nguyen et al, 2006) were also performed to characterize the Kerr nonlinearity. In comparison, the value of n 2 obtained in doped silica glass is approximately 5 times larger than that found in standard fused silica, consistent with Miller's rule (Boyd, 2008).…”