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|1. (WO2018105549) WAVELENGTH-SWEPT LIGHT SOURCE, METHOD FOR GENERATING DRIVE DATA FOR WAVELENGTH-SWEPT LIGHT SOURCE, AND OPTICAL DEFLECTOR|
|Applicants:||NIPPON TELEGRAPH AND TELEPHONE CORPORATION
|Title:||WAVELENGTH-SWEPT LIGHT SOURCE, METHOD FOR GENERATING DRIVE DATA FOR WAVELENGTH-SWEPT LIGHT SOURCE, AND OPTICAL DEFLECTOR|
The present invention address the problem of an SS-OCT device that, while the intensity of an interference signal increases as the coherence length of light from a wavelength-swept light source becomes longer, it has been difficult to maintain a long coherence length state over an entire wavelength band for wavelength-sweeping in the case of a conventional wavelength-swept light source in which temporally constant current injection is performed with respect to a gain medium, resulting in a decrease in the PSF intensity which directly impacts the quality of an output image from the SS-OCT device. In a wavelength-swept light source according to the present invention, a long coherence length state of output light is maintained over an entire swept-wavelength band. In correspondence to the wavelength-sweeping, the gain of the gain medium is varied over time and is maintained in a maximum coherence length state. Over the entire swept-wavelength band, the gain of the gain medium is maintained in a near-oscillation threshold state to narrow the unsaturated gain bandwidth of the gain medium. Also disclosed are an SOA current wavelength data acquisition method for driving while maintaining a long coherence length state, a novel coherence length measuring method, and an optical deflector suitable for a wavelength-swept light source.