Programmable frequency reference for laser frequency stabilization, and arbitrary optical clock generator, using persistent spectral hole burning
AssigneeThe Research and Development Institute, Inc.
InventorsPeter B. Sellin, Nicholas M. Strickland, John L. Carlsten, Rufus L. Cone
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Abstract
Techniques for stabilizing a laser (110) at a selectable frequency include splitting an output beam from an electrically adjustable laser into a first beam (369) and a second beam (361). The second beam is transmitted through a modulator (112). Then the second beam is transmitted through a spectral hole burning material (310) onto a detector (120). The laser is electronically adjusted in response to a detector output from the detector which senses the changes in the modulated second beam after it passes through the spectral hole burning material.
Claims22
A method for stabilizing a laser at a selectable frequency, the method comprising the steps of:
- splitting an output beam from an electrically adjustable laser into a first beam and a second beam;
- transmitting the second beam through a modulator;
- after transmitting the second beam through the modulator, transmitting the second beam through a spectral hole burning material onto a detector;
- and
- electronically adjusting the laser in response to a detector output from the detector.
A method for producing light pulses at a beat frequency, the method comprising the steps of:
- producing a first frequency stabilized laser beam at a first frequency, said step of producing the first frequency stabilized laser beam including
- transmitting a first output beam from an electronically adjustable first laser through a first spectral hole burning material with a spectral hole at the first frequency onto a first detector, and
- electronically adjusting the first laser based on a first frequency difference between the first output beam and the first spectral hole, said first frequency difference analyzed from a first detector output from the first detector;
- producing a second frequency stabilized laser beam at a second frequency different from the first frequency by an amount related to the beat frequency, said step of producing the second frequency stabilized laser beam including
- transmitting a second output beam from an electronically adjustable second laser through a second spectral hole burning material with a spectral hole at the second frequency onto a second detector, and
- electronically adjusting the second laser based on a second frequency difference between the second output beam and the second spectral hole, said second frequency difference analyzed from a second detector output from the second detector;
- and
- merging the first and second frequency stabilized laser beams to interfere with each other.
A method for producing light pulses at a beat frequency, the method comprising the steps of:
- producing a set of more than two frequency stabilized beams having a corresponding set of target frequencies, the set of target frequencies selected to produce a predetermined beat pattern, wherein producing each beam of the set of more than two frequency stabilized beams comprises
- transmitting an output beam from an electronically adjustable laser through a spectral hole burning material with a spectral hole at a corresponding frequency of the set of target frequencies onto a detector, and
- electronically adjusting the laser based on a frequency difference between the output beam and the spectral hole, said frequency difference analyzed from a detector output from the detector;
- and
- merging the set of more than two frequency stabilized beams to interfere with each other.
A spectral hole burning material for stabilizing a laser frequency at a target frequency with a target laser line width, wherein
- said material has a set of homogeneous absorption lines;
- a particular line of said set of homogeneous absorption lines has a particular center frequency at the target frequency.
A system for producing a laser beam locked at a selectable frequency with a laser line width, the system comprising:
- an electrically adjustable laser producing an output beam with an output beam frequency;
- a splitter for splitting the output beam into a first beam and a second beam on a second beam axis;
- a modulator on the second beam axis for applying a radio frequency signal to modulate a frequency of the second beam;
- a spectral hole burning material on the second beam axis after said modulator for transmitting a reference beam on a reference beam axis, said spectral hole burning material subject to forming a homogeneous spectral hole at the selectable frequency;
- a detector on the reference beam axis for producing a detector signal related to the reference beam;
- and
- servo electronics for electronically adjusting the output beam frequency based on a difference between the radio frequency signal and the detector signal.
A clock for producing light pulses at a beat frequency, the clock comprising:
- an electrically adjustable first laser producing a first output beam with an first output beam frequency on a first output beam axis;
- a first spectral hole burning material on the first beam axis for transmitting a first reference beam on a first reference beam axis, said first spectral hole burning material subject to forming a homogeneous spectral hole at a first selectable frequency;
- a first detector on the first reference beam axis for producing a first detector signal related to the reference beam;
- first servo electronics for electronically adjusting the first output beam frequency based on a difference between a frequency of the first output beam and the first detector signal;
- an electrically adjustable second laser producing a second output beam with a second output beam frequency on a second output beam axis;
- a second spectral hole burning material on the second beam axis for transmitting a second reference beam on a second reference beam axis, said second spectral hole burning material subject to forming a homogeneous spectral hole at a second selectable frequency different from the first selectable frequency by the beat frequency;
- a second detector on the second reference beam axis for producing a second detector signal related to the reference beam;
- second servo electronics for electronically adjusting the second output beam frequency based on a difference between the second output beam frequency and the second detector signal;
- and
- a optical joint for combining the first output beam with the second output beam.
Dependencies are inferred from the claim text.