Development of fiber optic probes and a dual wavelength laser system for medical applications

Abstract

Optical fibers have been widely used in the past several decades due to their characteristics, such as laser energy transmission, low optical loss and different beam shape. These features make them advantegous for different applications in a number of fields such as telecommunication, imaging, laser cavity systems and medical applications. Fiber optic probes were developed to use optical fiber systems in medicine since they are exible, small in diameter, easy to use and they transmit the laser energy through the target tissue of the body without any additional optical alignment. The tip geometry of the fiber optic probes can be changed so that the laser radiation is emitted with different shapes. Flat-ended, side-firing, radial, double radial and diffusing fiber optic probes, having different beam shapes, were developed by using mechanical polishing and also, CO2 laser polishing technique was demonstrated for fining radial fiber tips for the first time throughout this study. The probes were analyzed in terms of ray tracing, Zemax modelling, fabrication and light de ection. As a result, the spatial distribution of the fabricated probes were optimized. Different beam shapes originating from each fiber optic probe can serve for specific purposes. One of them is to use the diffusing probe as a cladding light stripper (CLS) in the fiber laser cavity since it improves the beam quality of the fiber laser. On the other hand, endovenous laser ablation (EVLA) is one of the operations that at, radial and double radial probes are preferred for ablating the varicose vein re ux, which is a common disease seen in 25% of women and 15% of men in the USA. A dual-wavelength medical laser system (980nm-1470nm), operating both at continuous wave (cw) and pulsed wave (pw), was also developed and characterized in terms of spectrum, power and pulse duration. A whole medical laser system consisting of the home-made radial fiber optic probe and the dual-wavelength medical laser system was assembled. In conclusion, design, development and characterization of the fiber optic probes having different beam shapes were performed and two different applications, namely CLS and a dual-wavelength medical laser system, were presented.