Fiber delivery of intense laser radiation is important for a broad range of application sectors, from medicine through to industrial laser processing of materials, and offers many practical system benefits relative to free space solutions. In recent years, photonic crystal fiber technology has revolutionized the dynamic field of optical fibers, bringing with them a wide range of novel optical properties that make them ideally suited to power delivery with unparalleled control over the beam properties. The DTI funded project: Photonic Fibers for Industrial beam DELivery (PFIDEL), aims to develop novel fiber geometries for use as a delivery system for high power industrial lasers and to assess their potential in a range of "real" industrial applications. In this paper we review, from an industrial laser user perspective, the advantages of each of the fibers studied under PFIDEL. We present results of application demonstrations and discuss how these fibers can positively impact the field of industrial laser systems and processes, in particular for direct write and micromachining applications.
Fiber delivery of intense laser radiation is important for a broad range of application sectors, from medicine through to industrial laser processing of materials, and offers many practical system design and usage benefits relative to free space solutions. Optical fibers for high power transmission applications need to offer low optical nonlinearity and high damage thresholds. Single-mode guidance is also often a fundamental requirement for the many applications in which good beam quality is critical. In recent years, microstructured fiber technology has revolutionized the dynamic field of optical fibers, bringing with them a wide range of novel optical properties. These fibers, in which the cladding region is peppered with many small air holes, are separated into two distinct categories, defined by the way in which they guide light: (1) index-guiding holey fibers (HFs), in which the core is solid and light is guided by a modified form of total internal reflection, and (2) photonic band-gap fibers (PBGFs) in which guidance in a hollow core can be achieved via photonic band-gap effects. Both of these microstructured fiber types offer attractive qualities for beam delivery applications. For example, using HF technology, large-mode-area, pure silica fibers with robust single-mode guidance over broad wavelength ranges can be routinely fabricated. In addition, the ability to guide light in an air-core within PBGFs presents obvious power handling advantages. In this paper we review the fundamentals and current status of high power, high brightness, beam delivery in HFs and PBGFs, and speculate as to future prospects.
In order to change the way that school children view physics, OSA's University of Southampton Student Chapter has developed an optic roadshow. By taking simple optics experiments and demonstrations to primary schools we aim to dispel the negative image of classroom science and help teachers to convey the fascination of physics.
The combination of wavelength-scale features and design flexibility offered by holey fibers leads to a significanlty broader range of optical properties than is possible in conventional optical fibers. Of particular interest, holey fibers offer the combination of broadband single mode guidance and large mode areas, and such fibers are promising for high power delivery applications such as including laser welding and machining, and for fiber lasers and amplifiers. Holey fiber technology has now reached the point that km-lengths of polymer-coated fiber with less than 1 dB/km loss at 1550nm are possible. As well as being of fundamental scientific interest, the novel guidance properties of holey fibers can be exploited to develop technologically important devices. Here recent advances in holey fibers will be presented, with a particular focus on recent results in developing holey fiber-based lasers.