Ultrawidely tunable single-mode fiber acousto-optic filter

Abstract

A single-mode fiber (SMF) acousto-optic tunable filter (AOTF) with a tuning range of more than 300 nm is demonstrated. The SMF used in the experiment has a ring of symmetric holes within the cladding, which causes a larger mode-index difference between the first and the second higher-order antisymmetric modes than those of a conventional SMF. As a result, the difference in beatlengths between the core mode and the higher-order modes is highly increased, which makes it possible for the SMF AOTF to exhibit a single resonance peak in the transmission spectrum over the wavelength range of 1.3-1.6 μm for given acoustic frequencies of 3.1-3.8 MHz.

Improved time-resolved acousto-optic technique for optical fiber analysis of axial non-uniformities by using edge interrogation

“…A flexural elastic wave propagating along an optical fiber creates a periodic refractive-index perturbation that can cause coupling between the core mode and co-propagating cladding modes [9,10]. In a single-mode fiber, coupling between the core and a cladding mode produces a notch in the spectrum of the light transmitted.…”

Narrowband fast tunable acousto-optic filter based on dispersion-compensating fiber

“…All-fiber acousto-optic tunable filters (AOTFs) 1 have been widely used in many fields, such as tunable lasers [2][3][4] , wavelength division multiplexing (WDM) optical communication [5][6][7] , optical signal processing 8,9 and so on. The all-fiber AOTF is considered to be a good candidate for the tunable add-drop filter (ADF) due to its high tuning speed 10,11 , large wavelength tuning range 12,13 , tunable coupling efficiency 14 , and compatibility with optical fiber system. Many efforts have been made to realize practical acousto-optic add-drop filter (AOADF) with robustness, low insertion loss, and in some cases, zero frequency shift.…”

Acousto‐optic mode coupling excited by superimposed flexural waves in a solid‐core microstructured optical fiber with hexagonal air‐hole array cladding

“…In some early related studies, flexural wave modulation was usually used owing to its relatively simple operation method, in which the acoustic waves are normally applied along the fiber axis to introduce periodic refractive index modulation (RIM) that leads to the formation of acoustically induced equivalent long‐period gratings . Particularly in recent years, with the fabrication technique progress of microstructured optical fibers (MOFs), much efforts have been put in investigations of the unique AO effects in different MOFs, including multimode solid‐core MOF , solid‐core photonic bandgap (PBG) MOF with liquid‐filled air‐hole cladding , hollow‐core PBG MOF , highly birefringent MOF , and single‐mode MOF with ring‐like air‐hole cladding , etc.…”