Hollow core anti-resonant fiber with split cladding

Abstract

An improved design for hollow core anti-resonant fibers (HAFs) is presented. A split cladding structure is introduced to reduce the fabrication distortion within design tolerance. We use numerical simulations to compare the Kagome fibers (KFs) and the proposed split cladding fibers (SCFs) over two normalized transmission bands. It reveals that SCFs are able to maintain the desired round shape of silica cladding walls, hence improving the confinement loss (CL) compared to the KF and is comparable to that of the nested antiresonant nodeless fiber (NANF) with the same core size. In addition, the SCF allows stacking multiple layers of cladding rings to control the CL. The influences of the number of cladding layers and the cladding gap width on the CL of the SCFs have been studied. SCF with three cladding rings is fabricated by the stack-and-draw technique. A measured attenuation spectrum matches well with the calculation prediction. The measured near field mode patterns also prove the feasibility of our fiber design.

Single-mode, low loss hollow-core anti-resonant fiber designs

“…Contrarily to HC-PBGs, surface modes can easily be suppressed in HC-AR fibers [32] and, thus, SSL can be reduced by one order of magnitude [6,29]. In order to control the modal content and attenuation, several types of HC-AR fibers have been proposed, investigated, and fabricated, including HC-AR fibers with circular anti-resonant tubes [4,10,[38][39][40][41], "ice-cream cone" shape anti-resonant tubes [41,42], elliptical anti-resonant tubes [43], nested anti-resonant tubes [5,6,11], as well as cladding tubes with even more complex shapes [44]. Recently, Debord et al [38] demonstrated a single ring HC-AR fiber with 8 non-touching circular tubes with a propagation loss of 7.7 dB/km at 750 nm and a bend loss of 0.03 dB/turn at a bend radius of 15 cm.…”

Function of second cladding layer in hollow core tube lattice fibers

“…The simplified structure features a negative core curvature, a non-touching core boundary and one tube cladding layer 16, 19, 22, 23 , thus often being named as Tube Lattice Fiber (TLF) 24–26 . The negative curvature is found to enhance the coupling inhibition between the core and cladding modes 27–29 while the non-touching core boundary helps to reduce a loss caused by the Fano-resonance 21, 30 . Moreover, the simple one ring cladding is proven sufficient to offer efficient light guidance 18, 31 .…”

A Method to Process Hollow-Core Anti-Resonant Fibers into Fiber Filters

“…The other type of HC-PCF is the so-called Hollow-Core Anti-Resonant Fibers (HC-ARFs), the guiding property relies of which on the combination of anti-resonance and inhibited coupling to low density of states cladding modes [7,8]. The HC-ARF has received ever-increasing interest thanks to its multiple broad transmission bands [7,9], simple and flexible cladding structures [10][11][12][13] and relatively low transmission loss [8,[14][15][16]. The HC-ARFs show promising prospects in applications such as delivering light with a wide spectral range from ultra violet to mid-infrared [17,18], an optofluidic system [19,20] and light gas interaction [21].…”