Spectral hole burning data storage system and method
AssigneeInternational Business Machines Corporation
InventorsCarl M. Jefferson, Alfred J. Meixner
Life of this patent
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Abstract
Phase modulation is used to record data in a spectral hole burning material. A laser and a phase modulator are used to generate both a reference pulse and a phase modulated data pulse to the material. The data is recorded as spectral holes in the absorption spectrum of the material. In order to read the data, a second reference pulse is generated which creates an echo pulse from the material. This echo pulse is combined with a frequency shifted comparator pulse in order to generate a heterodyne signal. A phase sensitive demodulator detects the phase transitions in the heterodyne signal and generates a digital signal representative of the data recorded.
Claims16
A data storage system comprising:
- an inhomogeneously broadened material;
- a means for generating a reference optical pulse directed at the material;
- a means for generating a phase modulated optical data pulse directed at the material;
- a means for generating a comparison optical pulse;
- an optical detection means for receiving an optical echo pulse from the material and for receiving the comparison optical pulse;
- and
- a phase detection means connected to the optical detection means for generating a data signal.
A data storage system comprising:
- a laser;
- a beamsplitter in optical communication with the laser;
- a first optical gate in optical communication with the beamsplitter;
- an optical phase modulator in optical communication with the first gate;
- a means for controlling the phase modulator responsive to data to be recorded, connected to the phase modulator;
- an inhomogeneously broadened material in optical communication with the optical phase modulator;
- a second optical gate in optical communication with the inhomogeneously broadened material;
- an optical frequency shifter in optical communication with the beamsplitter;
- a beam combiner in optical communication with the second gate and the optical frequency shifter;
- an optical detector in optical communication with the beam combiner;
- and
- a phase detector connected to the optical detector.
A method for data storage comprising the steps of:
- transmitting a reference optical pulse to an inhomogeneously broadened material having spectral holes burned therein as a result of a phase modulated optical data pulse;
- receiving at an optical detector an echo pulse from the material and a comparison optical beam, the comparison optical beam being of a frequency different from the reference pulse, and generating an electrical signal responsive thereto;
- and
- detecting phase transitions in the electrical signal and generating a digital signal.
Dependencies are inferred from the claim text.