Optical underwater communications systems employing tunable and fixed frequency laser transmitters

• Main Author: KEELER; R. NORRIS
• Format: Patent
• Language: English
• Published: 19.01.1993
• Subjects: ANALOGOUS ARRANGEMENTS USING OTHER WAVES; BASIC ELECTRIC ELEMENTS; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; DEVICES USING STIMULATED EMISSION; ELECTRIC COMMUNICATION TECHNIQUE; ELECTRICITY; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION ORRERADIATION OF RADIO WAVES; MEASURING; PHYSICS; RADIO DIRECTION-FINDING; RADIO NAVIGATION; TESTING; TRANSMISSION

The present invention uses tunable and fixed frequency lasers as an optical light source in underwater communications systems. This invention provides a high energy, short pulse length laser output which is tunable to or set at a desired wavelength. The tuning is used for performance optimization of the communications systems. An example of performance optimization is the tuning to or setting of the laser at the so-called Jerlov minimum, which is dependent upon the optical characteristics of the particular water used. The system described herein is used as an optical communications downlink employing one or more atomic resonance filter detectors. This invention has the effect of significantly improving the optical signal to noise ratio.