Fourier domain mode locking: method and apparatus for control and improved performance
AssigneeMassachusetts Institute of Technology
InventorsRobert A. Huber, James G. Fujimoto, Desmond C. Adler
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Abstract
A control system for improving and stabilizing Fourier domain mode locking (FDML) operation. The control system may also provide regulation of FDML operational parameters such as filter tuning, laser gain, polarization, polarization chromaticity, elliptical polarization retardance, and/or dispersion. The control system may be located internal to or external from the FDML laser cavity.
Claims24
A system to modify a wavelength swept waveform, the system comprising:
- a separating optical element to separate the wavelength swept waveform into at least two portions;
- a delay element to introduce a time delay between the at least two portions;
- and
- a recombination element to recombine the at least two portions upon introduction of the time delay, and
- wherein the time delay introduced by the delay element is selected so that the recombination element recombines at least the two portions of the wavelength swept waveform substantially without an overlap.
An FDML laser for generating light that is swept in a stepwise manner over a discrete series of optical frequencies, the FDML laser comprising:
- a gain element configured to amplify a wave having a wavelength;
- a time varying adjustably tunable wavelength selective filter element in communication with the gain element, the tunable filter element configured to selectively filter waves, the filter element being tuned in a time-varying, repetitive, periodic manner with a period T;
- an auxiliary wavelength selective filter element in communication with the tunable wavelength selective filter element, the auxiliary filter element configured to filter waves in a selectable manner, the auxiliary filter element having a plurality of transmission maxima within a gain bandwidth of the gain element;
- a feedback element in communication with the auxiliary filter element and the gain element;
- and
- a circuit including the time varying adjustably tunable wavelength selective filter element, the auxiliary wavelength selective filter element, the gain element, and the feedback element in a configuration in which the roundtrip time for the wave to propagate through the circuit is substantially equal to a non-zero integer multiple of the period T.
Dependencies are inferred from the claim text.