In this paper, we summarize the fundamental properties and review the latest developments in high power fiber lasers. The review is focused primarily on the most common fiber laser configurations and the associated cladding pumping issues. Special attention is placed on pump combination techniques and the parameters that affect the brightness enhancement observed in single-mode and multimode high power fiber lasers. The review includes the major limitations imposed by fiber nonlinearities and other parasitic effects, such as optical damage, transverse modal instabilities and photodarkening. Finally, the paper summarizes the power evolution in continuous-wave and pulsed ytterbium-doped fiber lasers and their impact on industrial applications.

High Power Fiber Lasers: A Review

* The only book describing applications of nonlinear fiber optics * Two new chapters on the latest developments: highly nonlinear fibers and quantum applications* Coverage of biomedical applications* Problems provided at the end of each chapterThe development of new highly nonlinear fibers - referred to as microstructured fibers, holey fibers and photonic crystal fibers - is the next generation technology for all-optical signal processing and biomedical applications. This new edition has been thoroughly updated to incorporate these key technology developments.The book presents sound coverage of the fundamentals of lightwave technology, along with material on pulse compression techniques and rare-earth-doped fiber amplifiers and lasers. The extensively revised chapters include information on fiber-optic communication systems and the ultrafast signal processing techniques that make use of nonlinear phenomena in optical fibers.New material focuses on the applications of highly nonlinear fibers in areas ranging from wavelength laser tuning and nonlinear spectroscopy to biomedical imaging and frequency metrology. Technologies such as quantum cryptography, quantum computing, and quantum communications are also covered in a new chapter.This book will be an ideal reference for: RD scientists involved with research on fiber amplifiers and lasers; graduate students and researchers working in the fields of optical communications and quantum information. * The only book on how to develop nonlinear fiber optic applications* Two new chapters on the latest developments; Highly Nonlinear Fibers and Quantum Applications* Coverage of biomedical applications

Applications of nonlinear fiber optics

Multiprotocol label switching (MPLS) is rapidly emerging as an Internet Engineering Task Force (IETF) standard intended to enhance the speed, scalability, and service provisioning capabilities in the Internet. MPLS uses the technique of packet forwarding based on labels, to enable the implementation of a simpler high-performance packet forwarding engine. This also decouples packet forwarding from routing, facilitating the provision of varied routing services independent of the packet forwarding paradigm. The authors track the evolution of this technology in relation to other existing technologies. Then an overview of the MPLS architecture and design is provided. In addition, some of the work that was a precursor to MPLS is discussed, as well as related issues and debates.

Evolution of multiprotocol label switching

Distributed optical fibre sensing, employing either Rayleigh, Raman, or Brillouin scattering, is the only physical-contact sensor technology capable of accurately estimating physical fields with spatial continuity along the fibre. This unique feature and the other features of standard optical fibre sensors (e.g., minimal invasiveness and lightweight, remote powering/interrogating capabilities) have for many years promoted the technology to be a promising candidate for geo-hydrological monitoring. Relentless research efforts are being undertaken to bring the technology to complete maturity through laboratory, physical models, and in-situ tests. The application of distributed optical fibre sensors to geo-hydrological monitoring is here reviewed and discussed, along with basic principles and main acquisition techniques. Among the many existing geo-hydrological processes, the emphasis is placed on those related to soil levees, slopes/landslide, and ground subsidence that constitute a significant percentage of current geohazards.

A Review of Distributed Fibre Optic Sensors for Geo-Hydrological Applications

We demonstrate the cascaded coherent collinear combination of a seed-split triplet of 1178nm high-power narrow-band (sub-1.5MHz) SBS-suppressed CW Raman fibre amplifiers via nested free-space constructive quasi-Mach-Zehnder interferometry, after analysing the combination of the first two amplifiers in detail. Near-unity combination and cascaded-combination efficiencies are obtained at all power levels up to a maximum P(1178) > 60W. Frequency doubling of this cascaded-combined output in an external resonant cavity yields P(589) > 50W with peak conversion efficiency eta(589) ~85%. We observe no significant differences between the SHG of a single, combined pair or triplet of amplifiers. Although the system represents a successful power scalability demonstrator for fibre-based Na-D(2a)-tuned mesospheric laser-guide-star systems, we emphasise its inherent wavelength versatility and consider its spectroscopic and near-diffraction-limited qualities equally well suited to other applications.

50W CW visible laser source at 589nm obtained via frequency doubling of three coherently combined narrow-band Raman fibre amplifiers

In this letter, we demonstrate that all-optical network subsystems, offering intelligence in the optical layer, can be constructed by functional integration of integrated all-optical logic gates and flip-flops. In this context, we show 10-Gb/s all-optical 2-bit label address recognition by interconnecting two optical gates that perform xor operation on incoming optical labels. We also demonstrate 40-Gb/s all-optical wavelength-switching through an optically controlled wavelength converter, consisting of an integrated flip-flop prototype device driven by an integrated optical gate. The system-level advantages of these all-optical subsystems combined with their realization with compact integrated devices, suggest that they are strong candidates for future packet/label switched optical networks

/pdf/all-optical-network-subsystems-using-integrated-soa-based-296vrtfywe.pdf

All-optical network subsystems using integrated SOA-based optical gates and flip-flops for label-swapped networks

Demonstration of all-optical packet switching at 160 Gb/s over a total of 110-km field installed optical fiber link is reported. The packet switch architecture is based solely on photonic circuits: an optical filter as label processor, an all-optical flip-flop as memory element and an ultrafast wavelength converter as router. Both flip-flop and wavelength converter uses semiconductor optical amplifiers which allows for photonic integration. The switch operates at low power levels and shows potential scalability. Error-free operation is shown without forward error correction technology.

160-Gb/s All-Optical Packet Switching Over a 110-km Field Installed Optical Fiber Link

Passive optical combiners have an unwanted 3-dB loss. This is avoided with optical switches, but these need control functions to synchronize with the optical signals. A nonlinear Mach-Zehnder interferometer can provide the combiner function without control signals. In the experiment reported here, this combiner was realized with a fiber component. Semiconductor optical amplifiers (SOAs) acted as the nonlinear phase shifting elements. Thus a proof-of-principle for the self-routing combiner is obtained: optical signals on either of the two input ports are guided to one and the same output port without any control mechanism in the interferometer. The nonlinear effect used is self-phase modulation, caused by carrier depletion in the SOAs as they approach saturation. The optical power at which the nonlinear switching occurred was about -2 dBm. The residual combiner loss was only 0.7 dB.

https://pure.tue.nl/ws/files/2301328/Metis145983.pdf

A Mach-Zehnder-interferometer-based low-loss combiner

The routing functionality by all-optically interconnecting semiconductor-based all-optical logic gates and flip-flops is demonstrated in the frame of an all-optical label swapping (AOLS) network. We experimentally show that the output of the all-optical 2-bit correlator is capable of toggling the states of the integrated flip-flop every 2.5 ns via an adaptation stage. High extinction ratios are obtained at the output of the flip-flop, which can be used to feed a high-speed wavelength converter to complete the routing functionality of the AOLS node. The potential integration of these semiconductor optical amplifier integrated Mach-Zehnder interferometer-based devices make the proposed approach a very interesting solution for future packet switched optical networks.

All-Optical Processing Based on a Logic xor Gate and a Flip-Flop Memory for Packet-Switched Networks

The routing functionality by all-optically intercon- necting semiconductor-based all-optical logic gates and flip-flops is demonstrated in the frame of an all-optical label swapping (AOLS) network. We experimentally show that the output of the all-optical 2-bit correlator is capable of toggling the states of the integrated flip-flop every 2.5 ns via an adaptation stage. High extinction ratios are obtained at the output of the flip-flop, which can be used to feed a high-speed wavelength converter to com- plete the routing functionality of the AOLS node. The potential integration of these semiconductor optical amplifier integrated Mach-Zehnder interferometer-based devices make the proposed approach a very interesting solution for future packet switched optical networks. Index Terms—Address recognition, all-optical signal processing, Mach-Zehnder interferometer (MZI), optical flip-flop, optical label swapping, packet switching, semiconductor optical amplifier (SOA).

http://ieeexplore.ieee.org/iel5/68/4285684/04287012.pdf

Yongzhi Liu

Papers

All-optical network subsystems using integrated SOA-based optical gates and flip-flops for label-swapped networks

160-Gb/s All-Optical Packet Switching Over a 110-km Field Installed Optical Fiber Link

A Mach-Zehnder-interferometer-based low-loss combiner

All-Optical Processing Based on a Logic xor Gate and a Flip-Flop Memory for Packet-Switched Networks

All-Optical Processing Based on a Logic XOR Gate and a Flip-Flop Memory for