Fiber Fuse

Light-Induced Continuous Breakdown of Silica Glass Optical Fiber

verfasst von: Shin-ichi Todoroki

Verlag: Springer Japan

Buchreihe : NIMS Monographs

Enthalten in: Springer Professional "Wirtschaft+Technik" , Springer Professional "Technik"

Einloggen, um Zugang zu erhalten

Über dieses Buch

This book describes the fiber fuse phenomenon that causes a serious problem for the present optical communication systems. High-power light often brings about catastrophic damage to optical devices. Silica glass optical fibers with ultralow transmission loss are not the exception. A fiber fuse appears in a heated region of the fiber cable delivering a few watts of light and runs toward the light source destroying its core region. Understanding this phenomenon is a necessary first step in the development of future optical communication systems. This book provides supplementary videos and photographs to help understand what occurs in the fiber, including the classification of its propagation mode and self-pumping effect. These findings are good references for other optical devices exposed to ultrahigh-power light such as laser emitters.

Inhaltsverzeichnis

Frontmatter

Chapter 1. Silica Glass Optical Fiber and Fiber Fuse

Abstract

There is serious concern in the telecommunication industry that the transmission capacity limit may be reached in the near future. One reason for this is the fiber fuse phenomenon, which is the continuous self-destruction of silica glass optical fiber induced and fed by propagating light. This phenomenon imposes an inevitable limit on the light power that can be handled by a fiber and prevents us from increasing the transmission capacity growth of optical communication. This chapter briefly reviews the basics of silica glass optical fibers and the fiber fuse phenomenon. The initiation of a fiber fuse is caused by the generation of a thermally decomposed product of silica glass. Its high absorbance results in a confined plasma (or optical discharge) propagating along the fiber core. This is due to the excellent heat resistance and low thermal conductivity of silica glass.

Shin-ichi Todoroki

Chapter 2. Fiber Fuse Propagation Modes

Abstract

The main challenge for experimenters on fiber fuses is that they move. This motion has been examined using ultrahigh-speed photography and the precise measurement of propagation speed for typical single-mode fibers. As a result, three propagation modes are defined depending on the plasma volume per pump beam diameter. In cylindrical and unimodal modes, the confined plasma fully occupies the core region and leaves periodic discrete voids or indiscrete thin voids, respectively. In the unstable mode, the cross-sectional area of the plasma is smaller than that in the other two modes and decreases with the pump power.

Shin-ichi Todoroki

Chapter 3. Periodic Void Formation

Abstract

Periodicity is the most impressive feature of fiber fuse damage. However, the damaging action wears a veil of blinding light emission. Therefore, periodic void formation process is reproduced as an animation of fused damage photographs. In cylindrical mode, periodic separation of a small void from the hollow silica melt behind the traveling plasma and successive asymmetric compression makes the void bullet-like shape. In addition, two types of periodic voids are seen in unstable mode. They are brought about by transient structural variation of the plasma tail.

Shin-ichi Todoroki

Chapter 4. Delayed Response of Silica Melt to Pump Modulation

Abstract

Periodic void formation has the function of a built-in clock made of silica melt, and its frequency is expected to shift with changes in pump power. Thus, the variation in the periodic void interval along the fiber length is precisely measured to determine the relationship with the pump power modulation. This analysis revealed the sub-millisecond order delayed response of the silica melt. Moreover, a large power jump suspends the clock and leave a void-free segment or a long void until the melt restores its state of thermal equilibrium.

Shin-ichi Todoroki

Chapter 5. Conclusion

Abstract

For a quarter of a century since its discovery, the fiber fuse has been recognized as a moving point without an internal structure as briefly summarized in Chap. 1. Through the discussions provided in the subsequent three chapters, a better model is proposed consisting of a hollow silica glass melt confining plasma and is found to be effective in describing fiber fuse propagation and void formation in typical single-mode fibers.

Shin-ichi Todoroki

Backmatter

Titel: Fiber Fuse
verfasst von: Shin-ichi Todoroki
Verlag: Springer Japan
Electronic ISBN: 978-4-431-54577-4
Print ISBN: 978-4-431-54576-7
DOI: https://doi.org/10.1007/978-4-431-54577-4