39 results about "Chip-scale atomic clock" patented technology

A chip scale atomic clock is disclosed that provides a low power atomic time / frequency reference that employs direct RF-interrogation on an end-state transition. The atomic time / frequency reference includes an alkali vapor cell containing alkali atoms, preferably cesium atoms, flex circuits for physically supporting, heating, and thermally isolating the alkali vapor cell, a laser source for pumping alkali atoms within the alkali vapor cell into an end resonance state by applying an optical signal along a first axis, a photodetector for detecting a second optical signal emanating from the alkali vapor cell along the first axis, a pair of RF excitation coils for applying an RF-interrogation signal to the alkali atoms along a second axis perpendicular to the first axis, a pair of bias coils for applying a uniform DC magnetic field along the first axis, and a pair of Zeeman coils for applying a Zeeman interrogation signal to the alkali atoms and oriented and configured to apply a time-varying magnetic field along the second axis through the alkali vapor cell. Another flex circuit is used for physically supporting the laser source, for heating the laser source, and for providing thermal isolation of the laser source. The laser source can be a vertical cavity surface emitting laser (VSCEL). The bias coils can be Helmholtz coils.

A method of making alkali-metal vapor cells by first forming microscale-wax micropackets with alkali metals inside allows fabrication of vapor cells at low cost and in a batch fabricated manner. Alkali metals are enclosed in a chemically inert wax to preform alkali metal-wax micropackets, keeping the alkali metals from reacting with the ambient surroundings during the vapor cell fabrication. This enables the deposition of precise amounts of pure alkali metal inside the vapor cells. Laser ablation of the alkali metal-wax micropackets provides a simple and effective way of releasing the enclosed metal. The method reduces the cost of making chip-scale atomic clocks and allows shipping of alkali vapor packets without contamination issues, thereby creating a technology for alkali-metal vendors to provide small packets of alkali metals.

A system and method for routing digital audio data synchronized where the source and destination units are synchronized to individual, local chip-scale atomic clocks. A source unit receives audio data and digitizes the data in synchronization to a local atomic clock. The data is transmitted via a communications network to at least one destination unit that receives the network transmitted data, decodes and reconstructs the data in synchronization with its own local atomic clock, and outputs the data to an audio destination.

A method of synchronizing the transmission and receipt of messages by radios within a wireless communications network. It is assumed that the radios have chip scale atomic clocks, which are externally synchronized, such as by GPS, but only at the beginning of a mission. Each radio defaults to a sleep mode, in which its receive and transmit circuitry is inactive. Each radio stores a channel plan of pre-determined base transmit times, and calculates a worst case time drift between clocks and a propagation delay value between combinations of radios. At each base transmit time, if a radio has an outgoing message to transmit, it subtracts propagation delay from the base transmit time, and transmits only at that time. Also, for each base transmit time, each radio subtracts time drift, thereby determining a receive time window during which it listens for messages from other radios.