Experimental demonstration of fractional order differentiation using a long-period grating-based in-fiber modal interferometer

POVEDA-WONG, LUIS; CRUZ, JOSE LUIS; CUADRADO LABORDE, CHRISTIAN; CARRASCOSA, ANTONIO; ANDRES BOU, MIGUEL

OPTICS COMMUNICATIONS

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2016 vol. 380 p. 35 - 40

0030-4018

In this work we demonstrate both, experimentally and theoretically, thata long-period grating-based in-fiber modal interferometer can perform an all-opticalarbitrary-order fractional differentiation. Experimentally, we fractionallydifferentiated to the 0.5th order a secant hyperbolic-like pulse of 23 ps timewidth provided by a 1039.5 nm emission wavelength modelocked fiber laser, witha chirp parameter of −30. An analytical expression relating the fractionalorder of differentiation n with the characteristicsof the modal interferometer was also derived, with the purpose to simplify thedesign procedure. The proposal was corroborated also numerically. This devicemay find applications in real time phase recovery.