Mode locking methods and apparatus
AssigneeMassachusetts Institute of Technology
InventorsRobert Huber, Kenji Taira, James Fujimoto
Life of this patent
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Abstract
In one aspect the invention relates to a frequency varying wave generator. The generator includes a gain element adapted to amplify a wave having a wavelength; a time varying tunable wavelength selective filter element in communication with the gain element, the tunable filter element adapted to selectively filter waves during a period T; and a feedback element in communication with the tunable filter element and the gain element, wherein the tunable wavelength selective filter element, the gain element and the feedback element define a circuit such that the roundtrip time for the wave to propagate through the circuit is substantially equal to a non-zero integer multiple of the period T.
Claims139
A frequency varying wave generator comprising:
- a gain element adapted to amplify a wave having a wavelength;
- a time varying tunable wavelength selective filter element being adjustably tunable over a given periodic time T, and in communication with the gain element, the tunable filter element adapted to selectively filter waves;
- and
- a feedback element in communication with the tunable filter element and the gain element,
- wherein the tunable wavelength selective filter element, the gain element and the feedback element define a circuit such that the roundtrip time for the wave to propagate through the circuit is substantially equal to a non-zero integer multiple of the periodic time T.
An apparatus adapted for generating waves having temporally varying frequencies, the apparatus comprising:
- a gain element adapted for amplifying waves having different wavelengths;
- a time varying tunable wavelength selective filter element configured to be adjustably tunable over a given periodic time T;
- a feedback element in communication with the gain element and the tunable filter element
- the tunable filter element, gain element and feedback element defining a circuit such that the roundtrip time of the wave substantially equals a non-zero integer multiple of a periodic time T during which the tunable filter element is tuned.
A method of frequency sweeping a wave generator comprising a gain element, a tunable filter in communication with the gain element and a feedback element in communication with the tunable filter and the gain element, the tunable filter, gain element and feedback element defining a circuit, the method comprising the steps of:
- generating waves;
- and
- periodically tuning a tunable filter being adjustably tunable over a given periodic time T, such that the waves travel from the filter element through the circuit and back to the filter element during a time which is a non-zero integer multiple of time T.
A laser for generating light having time varying wavelengths, the laser comprising:
- a gain element having a spectral bandwidth;
- a time varying, tunable optical bandpass filter being adjustably tunable over a given period time T and having an optical pass band that is varied during the periodic time T;
- and
- a feedback element in communication with the gain element and the filter, forming a laser resonator, wherein the roundtrip time of the optical waves in the resonator is substantially equal to a non-zero integer multiple of the time T.
A laser for generating light having time varying frequencies, the laser comprising:
- a gain element having a spectral bandwidth;
- a tunable Fabry Perot filter having an optical passband that is tunable over a given periodic time T;
- and a feedback element in communication with the gain element and the filter, forming a laser resonator,
- wherein a roundtrip time of optical waves in the resonator is substantially equal to a non-zero integer multiple of the periodic time T.
A frequency varying wave generator comprising:
- a gain element adapted to amplify a wave having a frequency;
- a time varying tunable frequency selective filter element, including independently adjustable minimum and maximum frequency and adjustable tuning speed, in communication with the gain element, the tunable filter element adapted to selectively filter waves, where the filter element is tuned over a given period time T;
- and
- a feedback element in communication with the tunable filter element and the gain element, wherein the tunable frequency selective filter element, the gain element and the feedback element define a circuit such that the roundtrip time for the wave to propagate through the circuit is substantially equal to a non-zero integer multiple of the period T.
A frequency variable light source comprising:
- an optical gain element;
- a time varying tunable frequency selective filter element with adjustable temporal tuning characteristics in communication with the gain element, the tunable filter element adapted to selectively filter waves, where the filter element is tuned over a given periodic time T;
- and
- a feedback element in communication with the tunable filter element and the gain element, wherein the tunable frequency selective filter element, the gain element and the feedback element define a circuit such that the roundtrip time for the wave to propagate through the circuit is substantially equal to a non-zero integer multiple of the period T.
A frequency variable light source comprising:
- an optical gain element;
- a time varying tunable frequency selective filter element with adjustable temporal tuning characteristics in communication with the gain element, the tunable filter element adapted to selectively filter waves, where the filter element is tuned over a given periodic time T;
- and
- a feedback element in communication with the tunable filter element and the gain element, wherein the tunable frequency selective filter element, the gain element and the feedback element define a circuit such that the roundtrip time for the wave to propagate through the circuit is substantially equal to a non-zero integer multiple of the period T with a timing error of less than 0.01% of the period T.
A frequency variable light source comprising:
- an optical gain element;
- a time varying tunable frequency selective filter element with adjustable temporal tuning characteristics in communication with the gain element, the tunable filter element adapted to selectively filter waves, where the filter element is tuned over a given periodic time T;
- and
- a feedback element in communication with the tunable filter element and the gain element, wherein the tunable frequency selective filter element, the gain element and the feedback element define a circuit such that the roundtrip time for the wave to propagate through the circuit is substantially equal to a non-zero integer multiple of the period T with a timing error smaller than the period T times the filter bandwidth divided by the tuning range.
A frequency varying wave generator comprising:
- a gain element adapted to amplify a wave having a frequency;
- a time varying tunable frequency selective filter element being adjustably tunable over a given period time T, and in communication with the gain element;
- and
- a feedback element in communication with the tunable filter element and the gain element, wherein the tunable frequency selective filter element, the gain element and the feedback element define a circuit such that the roundtrip time for the wave to propagate through the circuit is approximately, but not equal to a non-zero integer multiple of the period T.
Dependencies are inferred from the claim text.