Optical underwater communications systems employing tunable and fixed frequency laser transmitters
AssigneeKaman Aerospace Corporation
InventorR. Norris Keeler
Life of this patent
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Abstract
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.
Claims30
A method for underwater communication between a first above water location and a second underwater location, the first location including a laser transmitter positioned to transmit laser light toward the second location, comprising:
- tuning or setting the operational wavelength of the laser transmitter to a selected wavelength, said selected wavelength being selected so as to optimize the performance of said laser transmitter with at least one of (1) the depth of the water at the second location and (2) the Jerlov Class of the water at the second location;
- generating short pulses of light from the laser transmitter in accordance with a selected message to be communicated;
- projecting said short pulses of light toward the underwater location and at first filter receiver means associated with the underwater location;
- detecting said pulses of light using said first filter receiver mans;
- and
- converting said detected pulses of light to said selected message.
An apparatus for underwater communication between a first above water location and a second underwater location, the first location including a laser transmitter positioned to transmit laser light toward the second location, comprising:
- means for tuning or setting the operational wavelength of the laser transmitter to a selected wavelength, said selected wavelength being selected so as to optimize the performance of said laser transmitter with at least one of (1) the depth of the water at the second location and (2) the Jerlov Class of the water at the second location;
- means for generating short pulses of light from the laser transmitter in accordance with a selected message to be communicated;
- means for projecting said short pulses of light toward the underwater location and at first filter receiver means associated with the underwater location;
- means for detecting said pulses of light using said first filter receiver means;
- and
- means for converting said detected pulses of light to said selected message.
Dependencies are inferred from the claim text.