A He-Ne laser beam is coupled into 50/125 micrometers monofil optical fiber with the aid of the free lens coupler, after that it entered into the laser pin through the fiber-optic connector. The attenuate coefficient of the lens coupler is adjusted continuously, from 0.5 dB to (infinity) . The laser pin is composed of inside pipe and outside pipe that they are all stainless steel pipe. The inside pipe pierce into the outside pipe. In the inside pipe there is a large core fiber, they are stuck to together to each other. In order to observe back blood, there is a hole of 0.3 mm in diameter on the flank of the outside pipe. When the laser pin stab into a vein, the blood is irradiated directly by the He-Ne laser beam. The laser pin can be used only once, for the price of the fiber-optic connector is lower.
|