Tunable acoustic gratings in solid-core photonic bandgap fiber

Abstract

We investigate acousto-optic long period grating resonances in a fluid-filled solid-core photonic bandgap fiber (PBGF). The acoustic grating design enables electrically tunable notches in each of the PBGF transmission bands, where both the center frequency and depth of the resonances can be varied. The measured intermodal beat length and resonance bandwidth are in good agreement with numerical simulations based on multipole method. We show that the highly dispersive nature of PBGF modes results in very narrow-band rejection for a given grating pitch.

Combined effects of optical and acoustic birefringence on acousto-optic mode coupling in photonic crystal fiber

“…In recent years, many reports have been made for PCF-based AO devices with interesting filter properties using flexural acoustic wave traveling along the fiber. [9][10][11]. One of the undesirable features observed in these AO filters was that the spectral shape of the filters was distorted having multiple resonance peaks [11,12].…”

“…[9][10][11]. One of the undesirable features observed in these AO filters was that the spectral shape of the filters was distorted having multiple resonance peaks [11,12]. Since the distortion of the filter spectrum will severely limit the practical applications of the filters, it is important to determine the origin of the phenomena and find ways to control it.…”

Long-period gratings based on Photonics crystal fibers and applications

“…However, the single material property of PCFs leads to non-photosensitivity to UV light, therefore FBGs and LPGs cannot normally be formed in PCFs by use of the conventional UV-written technique, unless a PCF with a Ge-doped photosensitive core is used [26]. Recently, several alternative methods for making LPGs in PCFs with non-photosensitive cores were introduced, including glass structure change [27], periodic structural and/ or residual stress relaxation induced by arc discharge or a CO 2 laser [28][29][30][31][32], refractive index modulation by periodically applied mechanical pressure [33] or by the use of an acoustic wave [34,35], and periodic drilling micro-holes with a femto-second laser [36].…”

Analysis on Transition between Index- and Bandgap-guided Modes in Photonic Crystal Fiber

“…All-solid photonic bandgap fiber (ASPBGF) is a type of bandgap-guiding PCF. This has been made of high refractive index material (HRIM) inserts embedded in a PCF preform or filled into PCF afterwards [8][9][10][11][12][13][14]. Unusual dispersive properties have been also observed in the fiber, so the ASPBGFs were often applied to femtosecond laser and amplifier developments [15][16][17].…”