Structural design and fabrication of hollow optical fiber for transmitting mid-infrared and visible light

Hollow optical fiber is an important means for transmitting mid-infrared laser radiations (e.g. 10.6 μm CO2 laser) in medical surgery applications. Presently it's still a challenge to establish a flexible, low-cost hollow fiber that can transmit the invisible mid-infrared light and the visible indicator light simultaneously. In this work, we selected flexible acrylonitrile butadiene styrene (ABS) plastic tubing and polymethylmethacrylate (PMMA) plastic optical fiber to fabricate a PMMA/ABS plastic tube-based hollow optical fiber. The ABS plastic tube with Ag/AgI plating on the inner surface was used to transmit CO2 laser. The PMMA plastic optical fibers integrated around the output end of the ABS tube-based Ag/AgI hollow fiber was used to deliver visible light. The results show that the CO2 laser transmission loss of this hollow fiber goes up from 0.74 to 1.22 dB/m as the bending angle increases from 0° to 120°. The 5-watt CO2 laser can be transmitted continuously for at least 6 minutes. The illumination of visible light transmitted through the PMMA plastic optical fibers can reach 1171 lux. Compared with conventional silica glass tube-based dualcore hollow fiber, the PMMA/ABS plastic tube-based hollow fiber is more robust, flexible and easy to couple. The PMMA/ABS plastic tube-based hollow optical fiber provides new ideas for transmitting invisible mid-infrared light and the visible indicator light simultaneously, which is expected to build a new laser surgery medical equipment.