Gte Sylvania Incorporated

Gte Government Systems Corporation

Dan J Radecki

Curt H Chadwick

Frederick W Martin

Paul J Titterton

Robert W Cotterman

Joseph D Tajnai

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 IFF code to identify the transceiver to the submarine. In the preferred embodiment the transmit optics spread the beam out into an elongated elliptically-shaped pattern to maximize coverage of the search area. When the downlink beam energy is within range of the submarine, an optical receiver on the submarine detects the beam, filters out the background light with a very narrow-band filter, and converts the light pulses to equivalent electrical pulse. A signal processor in the submarine receiver decodes the electrical pulses and verifies the IFF code to prevent the submarine from responding to a laser beam from an unfriendly source. If the IFF is verified, the submarine laser transceiver transmits a pulse-modulated uplink beam response at the same wavelength, but timed so that the light pulses are time interleaved with the downlink pulses. The uplink beam power is carefully controlled to the minimum power level required by the airborne receiver to recover the uplink beam. As soon as the airborne receiver verifies the uplink IFF code, communications being over the laser link for the duration of time that the airborne platform receiver is within range of the uplink beam. In one embodiment of this invention, both receivers employ a Cesium filled atomic resonance filter (ARF) to separate the blue-green beam from any background light.

Secure two-way submarine communication system

A method of providing secure tactical communications between a submerged submarine and an airborne platform using a pulse-modulated blue-green laser beam. During an initial acquisition mode, the airborne transceiver sends out a downlink laser beam to the ocean surface and below using a predetermined IFF code to identify the transceiver to the submarine. In the preferred embodiment the transmit optics spread the beam out into an elongated elliptically-shaped pattern to maximize coverage of the search area. When the downlink beam energy is within range of the submarine, an optical receiver on the submarine detects the beam, filters out the background light with a very narrow-band filter, and converts the light pulses to equivalent electrical pulses. A signal processor in the submarine receiver decodes the electrical pulses and verifies the IFF code to prevent the submarine from responding to a laser beam from an unfriendly source. If the IFF is verified, the submarine laser transceiver transmits a pulse-modulated uplink beam response at the same wavelength, but timed so that the light pulses are time interleaved with the downlink pulses. The uplink beam power is carefully controlled to the minimum power level required by the airborne receiver to recover the uplink beam. As soon as the airborne receiver verifies the uplink IFF code, communications begin over the laser link for the duration of time that the airborne platform receiver is within range of the uplink beam. In one embodiment of this invention, both receivers employ a Cesium filled atomic resonance filter (ARF) to separate the blue-green beam from any background light.

Secure two-way communications with submerged submarines

A laser pumping assembly with a housing having a removable heat resistant glass liner or shell enclosing a pump and a laser rod comprises removable glass or quartz plates over opposite ends of the shell together with a heat absorbing shim between each end plate and an adjacent heat conductive support plate attached to the housing. The outside surface of each end plate is coated with a dielectric layer which reflects the desired wavelength of pump lamp radiation inwardly of the shell toward the laser rod and transmits undesired wavelengths to the adjacent shim. The shims are held tightly against the end plates and pass heat from the unreflected pump lamp radiation to the respective support plates for dissipation in the cooling system.

Laser pumping assembly

An improved conductively cooled laser pumping assembly comprises a metallic housing having an elliptically shaped bore in which a pump lamp and laser rod are supported along the respective focal axes of the bore. The laser rod is mounted on the tapered end of a conductively cooled metal body by resilient strap means at opposite ends of the rod and with a relatively low melting temperature solder between the body and the rod to enhance thermal contact with the rod and to accommodate the different thermal expansions of the rod and body, thereby minimizing rod strain. The elliptical bore is coated with a heat absorbing substance and contains a similarly shaped one-piece snugly fitting removable glass liner or shell. The shell has removable glass or quartz end plates backed by heat absorbing shims and both the shell and end plates have a dielectric reflective-transmissive coating on their external surfaces for reflecting pump light toward the laser rod while transmitting radiation having unwanted wavelengths to the adjacent conductively cooled housing. The shell and end plates are resiliently axially biased as a unit within the housing to limit relative movement of these parts.

Growing community of inventors

San Jose, CA, United States of America

Dan J Radecki