Lasers in Surgery and Medicine 30:184±190 2002) Review Article Diode-Pumped Fiber Lasers: A New Clinical Tool? Stuart D. Jackson, PhD* and Antonio Lauto, MSc Optical Fibre Technology Centre, Australian Photonics CRC, The University of Sydney, 206 National Innovation Centre, Australian Technology Park, Eveleigh, 1430, Sydney, Australia Background and Objective: Diode-pumped ®ber lasers are a compact and an ef®cient source of high power laser radiation. These laser systems have found wide recogni- tion in the area of lasers as a result of these very practical characteristics and are now becoming important tools for a largenumberofapplications.Inthisreview,weoutlinethe basic physics of ®ber lasers and illustrate how a number of clinical procedures would bene®t from their employment. Study Design/Materials and Methods: The pump mechanisms, the relevant pump and laser transitions between the energy levels, and the main properties of the output from ®ber lasers will be brie¯y reviewed. The main types of high power ®ber lasers that have been demon- strated will be examined along with some recent medical applications that have used these lasers. We will also provide a general review of some important medical specialties, highlighting why these ®elds would gain from the introduction of the ®ber laser. Results/Conclusion: It is established that while the ®ber laser is still a new form of laser device and hence not commercially available in a wide sense, a number of im- portant medical procedures will bene®t from its general introduction into medicine. With the number of medical and surgical applications requiring high power laser radiation steadily increasing, the demand for more ef- ®cient and compact laser systems providing this capacity will grow commensurately. The high power ®ber laser is one system that looks like a promising modality to meet this need. Lasers Surg. Med. 30:184±190, 2002. ß 2002 Wiley-Liss, Inc. Key words: photocoagulation; medical lasers INTRODUCTION The requirements of the output from lasers used for medical and surgical applications are manifold. Apart from the important and well-recognised attributes such as the power or pulse energy) and the wavelength, other practical qualities such as the size, the maintenance level, and the input power requirements are especially vital if a new laser is going to receive widespread support from the medical community. Indeed, other laser characteristics, for exam- ple,thebeamqualitywhicheffectsthetightnessofthefocus of the output, may also be important for applications requiring a high degree of spatial discrimination. The primary lasers used in clinical applications are the argon ion, the CO 2 , and the Nd:YAG in either of the 1.064 mm, 1.319 mm, or 532 nm modes of output) and more recently, the Ho:YAG and Er:YAG lasers. All of these lasers are generally quite large in size and require water- cooling and sometimes three-phase power to operate. In addition, the Nd:YAG, Ho:YAG, and Er:YAG lasers use ¯ashlamps or arclamps for optical excitation; pump sources which generally require frequent replacement. Lasers based on lamp excitation, therefore, have regular periods of downtime. The relatively recent use of diode lasers as pump sources for some of these lasers, however, has signi®cantly reduced the level of non-activity of the medical laser. Of the large number of recent developments in laser technology, one of the more promising for direct applica- tion,isthehighpower®berlaser[1,2].Thesesystemshave the core of an optical ®ber doped with an ion that has a characteristic ¯uorescence when excited i.e., pumped). These lasers are highly ef®cient and compact. The high ef®ciency arises from the fact that the intense pump and laser ®elds are con®ned and co-propagate within the ®ber. A high degree of spatial con®nement and spatial overlap between the laser mode and the excited ion population over the entire length of low-loss) ®ber results in low thresholds and high slope ef®ciencies, and consequently, the input power consumption is comparatively low for a given level of output power. When diode lasers are used as the pump source for the ®ber laser, the overall system ef®ciency and compactness is very high and no water- cooling of the ®ber itself is required even when operated at very high power. In this paper, we describe and elucidate the important physical characteristics of the various types of ®ber lasers that have high potential in surgical and medical applications. We seek, with this review, to stimu- late the interest of physicians and medical researchers in these novel laser sources. Contract grant sponsor: Australian Research Council. *Correspondence to: Stuart D. Jackson, PhD, Optical Fibre Technology Center, Australian Phtonics CRC, The University of Sydney, 206 National Innovation Centre, Australian Technology Park, Eveleigh, Australia. E-mail: s.jackson@oftc.usyd.edu.au Accepted 6 November 2001 Published online in Wiley Interscience www.interscience.wiley.com). DOI 10.1002/lsm.10023 ß 2002 Wiley-Liss, Inc.