EFFECT OF OCEAN SURFACE ON LASER COMMUNICATION LINK FROM GROUND TO SUBMARINE.

Normal communication link with submerged bodies in the VLF range has serious practical limitations besides providing limited bandwidth capabilities. Optical communication links are thus being studied as an alternative possibility. It is now known that a window exists in the blue/green region of the optical spectrum, where the ocean water attenuation factors are very low. The ground-submarine link via a satellite has to necessarily contend with propagation through the atmosphere, ocean and air-water interface. The vagaries of the air-water interface on the reliability of the optical communication link have been studied both theoretically and experimentally and the results presented. It is observed that as long as the diameter of the optical beam incident on the interface is comparable to the ocean wavelength, the attenuation of the received underwater optical intensity is never more than 50 percent of what it would have been without ocean waves.