Fiber Fuse Propagation and Its Suppression in Hole-Assisted Fibers

Abstract

SUMMARYWe examined the characteristics of fiber fuse propagation in hole-assisted fibers (HAF). The fiber fuse propagated in the same way as in conventional single-mode fiber (SMF) when the diameter of an inscribed circle linking the air holes (c) was much larger than the diameter of the melted area (D melted ). The melted area is caused by fiber fuse propagation and D melted is assumed to be almost the same size as the plasma. However, when c was much smaller than D melted , the fiber fuse did not propagate in HAF with input powers above 15 W at 1480 and 1550 nm. This result indicates that the threshold power of fiber fuse propagation in HAF can be at least 10 times larger than that in conventional SMF in the optical communication band. We also observed the dynamics of fiber fuse termination at a splice point between HAF and a conventional fiber by using a high-speed camera, when c was much smaller than D melted . We consider that the reduction in gas density caused by the air holes results in fiber fuse termination. When c was almost the same as D melted , we observed a new propagation mode and its dynamics for a fiber fuse with a damage track whose period was approximately 30 times longer than that in conventional SMF. We also made the first observation of a new threshold power (upper threshold) for a fiber fuse. key words: hole-assisted fiber (HAF), fiber fuse, high power

Fiber Fuse Propagation Behavior

“…Thus, it is possible to use this fiber to make a fiber fuse terminator. Kurokawa & Hanzawa (2011) observed a fuse termination in situ at a splice point between PCF and conventional fiber. Ha et al (2011) proposed another terminator using a hollow optical fiber.…”

Simulation of Fiber Fuse Phenomenon in Single-Mode Optical Fibers

“…Similarly, Kurokawa and Hanzawa investigated the power dependence of both the propagation velocity v f for the SMF and L p for HAF2 at λ 0 = 1.48 µm [46]. When a laser light of P 0 = 8.1 W was input into HAF2, the observed v f for the SMF was 1.1 m/s and L p for HAF2 was ≃ 80 µm.…”

“…The constant D melted value (about 20-22 µm) was almost equal to the D hole value (21.2 µm) of HAF2 + in the P 0 range of 2.0-8.1 W. Therefore, an increase in penetration length observed in HAF2 + for P 0 ≤ 2 W was considered to be induced by the reduction of plasma size. On the other hand, D melted of an SMF increased monotonously with increasing P 0 in the P 0 range of 4-14 W [46].…”

“…Several researchers observed the dynamics of fiber fuse termination near a splice point between a HAF and an SMF by using a high-speed camera [42], [46], [48], [51].…”

“…The fiber fuse propagation in a HAF is affected by both the diameter of an inscribed circle linking the air holes (D hole ) and the diameter of the air hole (d h ) (see Figure 2). No propagation of fiber fuse was observed in HAFs with d h = r c = 4.5 µm and a ratio R h of the D hole to the core diameter (2 r c ) of 2 or less when the laser power P 0 of 13.5 and/or 15.6 W at λ 0 = 1.48 + 1.55 µm was incident to HAFs [43], [45], [46].…”