Self-referenced locking of optical coherence by single-detector electronic-frequency tagging
AssigneeThe United States of America as represented by the Secretary of the Air Force
InventorThomas M. Shay
Life of this patent
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Abstract
A coherent laser beam combining system wherein the output of a single master oscillator is split into a plurality of signals, the signals are electronically modulated at unique frequencies. One signal is designated a reference signal while the remaining signals are passed through phase adjusters. All signals are optically amplified, aligned and passed through a beam splitter to split off a small sample that is imaged onto a photodetector. The photodetector output is fed to a signal processor that produces phase error signals that drive the phase adjusters resulting in a high-powered optically coherent output signal.
Claims5
A coherent laser beam combining system comprised of:
- a. a master oscillator having a laser output signal;
- b. a 1×N power splitter, whereby the output signal of the master oscillator is split into a plurality of N output signals;
- c. means for modulating each of the N output signals of said power splitter with a unique electronic frequency, wherein one of said N output signals is selected as a reference signal and the modulation frequencies are selected such that a beat note between said reference signal and the remaining (M=N−1) modulated slave signals can be uniquely isolated;
- d. M optical phase adjusting elements for receiving said M modulated slave signals and outputting M phase modulated signals;
- e. means for amplifying said N modulated output signals;
- f. means for optically co-aligning said N amplified signals;
- g. means for sampling said N optically aligned signals;
- h. an imaging system for directing said N sampled signals onto a photodetector;
- i. means for signal processing the output of said photodetector, thereby to isolate and extract phase control signals for each M slave signal and to apply said phase control signals to said M optical phase adjusting elements using negative feedback to cancel the phase difference between each M slave signal and said reference signal, thereby resulting in a high-powered optically-coherent laser beam output.
Dependencies are inferred from the claim text.