Efficient, narrowband LP01↔LP02 mode convertors fabricated in photosensitive fibre: spectral response

Optical switching method based on two diffraction gratings bistable system

“…This method is based on the fast modulation of the continuous wave optical beam pulses in order of picoseconds wide. The first articles presents a solution in which the optical switching threshold for the input signal was in order of hundreds watts [11]. Many works in the field of optical bistability phenomenon and optical switching aimed towards the development of methods for reducing the switching threshold.…”

Adaptive gain equalization on optical amplifiers based on the acousto-optic effect using a single long period grating

“…Since this kind of filter requires transmission characteristics of very low back reflection and wide bandwidth, long period grating (LPG) devices which operate in the transmission mode have found a role in these applications because of their excellent acting [8]. The LPG technology has been used in the development of optical communications devices [9,10] and physical parameters sensors [11,12]. A LPG is a special periodic grating, whose period is chosen in order to couple light from the guided fundamental mode of the fiber into the forward propagating cladding modes.…”

Effect of Ultrasound Acoustic Characteristics in Cattle Liver under Ultrasound Exposure

“…Small variations of these parameters result in significant peak position shifts. LPGs have applications as strain, bend, temperature, and refractive index change sensors [2][3][4], band-pass and bandrejection filters [3], gain equalizers [5], mode converters [6], light diffusers for medical applications [7] and chemical sensors [8]. A simple fibre-optic chemical sensor was constructed by inserting an unmodified fibre core into a capillary glass tubing [9].…”

“…In optical-fibre gratings, the phase-matching condition is described by [6] λ p = n core ef − n clad…”