Christopher C. Gregory

Hollow sapphire fibers for the delivery of CO(2) laser energy.

Hollow sapphire tubing has been used to deliver nearly single-mode CO(2) laser energy. The hollow single-crystal A1(2)O(3) fiber has an n < 1 cladding at 10.6 microm. Measured losses at 10.6 microm are as low as 0.49 dB/m, and the minimum bend radius of the 580, microm x 380 microm fiber is 14 cm. Bending losses are shown to vary as 1/R, and essentially only the HE(11) mode propagates in the bent guide.

Attenuation, modal, and polarization properties of n<1, hollow dielectric waveguides

The attenuation coefficients for hollow sapphire and lead-based, oxide glass waveguides are calculated using an approximate formalism from Marcatili and Schmeltzer [Bell Syst. Tech. J. 43, 1783-1809 (1964)]. These results are compared with an exact calculation, and the agreement is found to be excellent for bore diameters greater than 100 µm. Although the hollow lead glass waveguides have measured losses in agreement with theory, the hollow sapphire waveguides have losses greater than those calculated for the lowest-order mode. This excess loss is due to roughness of the inner surface of the sapphire. The hollow dielectric waveguides are also shown to preserve polarization and the single mode as do some of the hollow metallic waveguides.

High peak power CO 2 laser transmission by hollow sapphire waveguides

High peak power transverse excitation atmospheric CO(2) laser pulses are transmitted through flexible hollow sapphire waveguides with losses of 0.84 dB/m and no damage to the waveguides.

Hollow Waveguides For CO2 Laser Delivery Systems

A hollow waveguide made from alumina, ceramic tubing has been developed for use in delivering CO2 laser power in laser surgical applications. This hollow fiber is rigid and can deliver in excess of 70 watts of power with spot sizes less than 1 mm. The output beam is nearly TEMoo. with a full divergence angle of less than 3°. The attenuation of the hollow fibers varies from 0.4 to 1.5 dB/m depending on bore size. Using a special coupler, we attach the waveguides to the articulated arm of a CO2 laser. The fiber is then inserted into an endoscope for delivering power into the body.

Properties Of Alkali Halide Optical Fibers

Polycrystalline alkali halide fibers were fabricated using a hot extrusion technique. Core/clad fibers of KBr/KC1 had losses as low as 0.1 dB/m at 10.6 μm, but the average loss for 800/1000 μm fiber was 0.69 ± .32 dB/m. The salt fibers were coated with teflon to mini-mize surface fracture from microcleavage cracks and to protect the fiber from contamination. The maximum output power we have obtained from the fiber is 67 watts of cw CO2 laser power. This corresponds to a power density of 13.3 kW/cm2. The 1000 μsalt fiber has been bent into a 12 cm diameter circle with a 5% reduction in transmission.

Hollow sapphire fiber system for high-power CO2 lasers

Hollow sapphire fibers have been used to deliver up to 1500 W of CO2 laser power for industrial laser applications. These hollow waveguides incorporate a water jacket to prevent overheating. The fibers are about 110 cm in length and they have been bent to 90 degree(s). The bending loss for the large 1070-micrometers bore fiber is less than 15% of the straight loss.

Hollow curved Al2O3 waveguides for CO2 laser surgery

Alumina waveguides are bent to specific shapes by high temperature creep. Sapphire waveguides are mechanically bent, and both are plated with metal to form curved small diameter delivery systems for surgical CO2 laser radiation. The optical properties of these bent waveguides are presented as well as potential surgical uses including percutaneous laser discectomy.

Hollow alumina fibers for CO2 laser delivery systems

An articulated arm containing hollow-alumina waveguides has been developed for use with surgical, carbon-dioxide lasers. It has been demonstrated that this arm has excellent pointing ability and it can be used with micromanipulators, handpieces, and endoscopic-waveguides. This arm incorporates lower cost materials and much shorter assembly and alignment times than conventional articulated arms. A separate system has been developed for the combining of a carbon-dioxide laser beam delivered by an articulated arm with a Nd:YAG laser beam delivered by a fiber and the launching of the combined beams into an endoscopic alumina waveguide. This system can deliver more then 85% of the CO2 and over 40% of the Nd:YAG radiation to tissue.

Hollow Waveguides For CO[sub]2[/sub] Laser Delivery Systems

A hollow waveguide made from alumina, ceramic tubing has been developed for use in delivering CO2 laser power in laser surgical applications. This hollow fiber is rigid and can deliver in excess of 70 watts of power with spot sizes less than 1 mm. The output beam is nearly TEMoo. with a full divergence angle of less than 3°. The attenuation of the hollow fibers varies from 0.4 to 1.5 dB/m depending on bore size. Using a special coupler, we attach the waveguides to the articulated arm of a CO2 laser. The fiber is then inserted into an endoscope for delivering power into the body.

Hollow Waveguides For CO 2 Laser Delivery Systems

A hollow waveguide made from alumina, ceramic tubing has been developed for use in delivering CO2 laser power in laser surgical applications. This hollow fiber is rigid and can deliver in excess of 70 watts of power with spot sizes less than 1 mm. The output beam is nearly TEMoo. with a full divergence angle of less than 3°. The attenuation of the hollow fibers varies from 0.4 to 1.5 dB/m depending on bore size. Using a special coupler, we attach the waveguides to the articulated arm of a CO2 laser. The fiber is then inserted into an endoscope for delivering power into the body.