Fabrizio Carbone

Polarization-insensitive wavelength conversion in a lithium niobate waveguide by the cascading technique

In this letter, we present a polarization-insensitive wavelength conversion scheme based on the cascading of two second-order processes. The nonlinear device exploits a double pass configuration in a titanium indiffused waveguide realized on a periodically poled lithium-niobate substrate. Polarization-independent conversion efficiency is obtained by rotating the signal polarization state by means of a Faraday mirror. A polarization sensitivity lower than 0.8 dB is experimentally demonstrated.

Phase-matched nonlinear interactions in a holey fiber induced by infrared super-continuum generation

By coupling 110fs pulses at lambda=1.55µm into a 45cm long holey fiber, we observe the generation of a broadband continuum, followed by the appearance of a sharp blue line at 430nm. Blue light is generated in a high-order mode by a third-harmonic generation process that is phase-matched with the super-continuum component at 1.29µm. Such an interpretation is supported by measurements performed by using 1.29µm pulses and also by simulation. In addition we find that the choice of an input polarization tilted with respect to the fiber-birefringence axis can lead to the generation of new frequencies through a four-wave mixing process that exploits non-diagonal components of the third-order susceptibility.

NONLINEAR PROPAGATION OF ULTRASHORT LASER PULSES IN A MICROSTRUCTURED FIBER

The propagation of ultrashort laser pulses into a microstructured fiber having a large nonlinear coefficient is found to give rise to various nonlinear phenomena. By using an input wavelength in the range 1300–1550 nm, the observed output spectrum presents, besides supercontinuum generation, sharp lines due to third-harmonic generation and four-wave mixing. When the input wavelength is around 800 nm, close to the zero-dispersion wavelength, the solitonic propagation is accompanied by a very intense and narrow-band emission in the blue spectral region.

Carrier frequency hopping for optical pulse transmission in dispersion-managed fiber systems

Abstract We present a fiber transmission system combining dispersion management with periodical hopping of channel frequencies by means of wavelength converters. We show that the signal distortion arising from chirp reversal may be substantially suppressed for optimized dispersion-managed links. We exemplify some potentialities of all-optical frequency conversion to limit the third-order dispersion impairments and timing jitter in long-haul fiber systems based on chirped RZ modulation format.