An arrangement for secure two-way tactical laser communications between a submarine submerged in an ocean and an airborne platform. During an initital acquisition mode, the airborne transceiver sends a downlink pulse-modulated blue-green laser beam to the ocean surface and below using a predetermined...http://www.google.de/patents/US5038406?utm_source=gb-gplus-sharePatent US5038406 - Secure two-way submarine communication system
