The average price for a kilometer of fiber-optic cable critical for Russian battle drones has more than doubled in China, with some spot markets putting the increase as high as 400 percent, a major Russian business magazine reported on Thursday. Loaded onto a spool and unwinding behind a drone as it flies in battle, this high-tech component is made primarily of pure silicon. It is calibrated for ultra-fast data transmission between the drone and its operator and is impervious to jamming. JOIN