Antiresonant hollow core fiber with seven nested capillaries

Abstract

Abstract:We report an antiresonant hollow core fiber formed of 7 non-touching capillaries with inner tubes. The fiber has a core diameter of ~33µm and a core wall of ~780nm of thickness. We demonstrate robust single mode operation at 1064nm and broad transmission bandwidth.

Polarization-filtering and polarization-maintaining low-loss negative curvature fibers

“…The maximum number of antiresonant or resonant layers in any azimuthal direction is specified since a simple structure with fewer layers is easier to fabricate. Currently, nested negative curvature fibers, which have been fabricated, only have at most two glass layers in any azimuthal direction [31][32][33]. The fiber core shape is also compared because a circular core shape is easier to draw due to surface tension in the fiber drawing process.…”

“…Although the birefringence in our proposed structure is lower than in other fiber designs in Table 1, these other designs require either three glass layers in any azimuthal direction or a non-circular core shape. The feasibility of fabricating these more complex structures has not yet been demonstrated [31][32][33].…”

“…Figure 1(b) shows a negative curvature fiber structure with two nested tubes in the y-direction using a wall thickness close to the resonance condition. Negative curvature fibers with one nested tube in each major tube have been fabricated [31][32][33]. With proper design, the effective indices and mode profiles of the glass modes will be different for the x-and y-polarizations.…”

Record Low-Loss 1.3dB/km Data Transmitting Antiresonant Hollow Core Fibre

“…Similar fibres with <8 dB/km 8 have since been reported, an impressive loss level, but still too high for most data transmission applications It is now well known, that by adding a set of smaller nested tubes the loss of the fibre can theoretically be considerably reduced 9 . Various groups have reported good progress towards the realisation of such a Nested Antiresonant Nodeless Fibre (NANF), but all have so far failed to achieve the required structure/symmetry necessary for low loss 10,11 . Recently, a significant step towards the demonstration of a low loss ARF was reported using a modification of the NANF concept, where additional radial double reflections were obtained by inserting glass sheets in the stack 12 .…”

Recent Advancement of Anti-Resonant Hollow-Core Fibers for Sensing Applications

“…Finally, the suspended capillary tubes are optimized to be nested structures, as displayed in Figure 3c,d. In this way, the number of coherent reflections at the air-silica interface is increased and, thus, confinement loss is reduced, which is the latest HC-NANF [31,32]. All these AR-HCFs utilize the negative curvature effect in the surrounding region of the central core to reduce attenuation and promote longer propagation distance, so they are also referred to as negative curvature fibers (NCF).…”