Wavelength sweep light source, drive data generation method for wavelength sweep light source, and optical deflector

摘要

In the SS-OCT apparatus, the intensity of the interference signal increases as the coherence length of light from the wavelength swept light source increases. In the conventional wavelength swept light source in which a constant current is injected into the gain medium, the coherence length cannot be maintained in a long state over the entire wavelength band in which the wavelength is swept. There is a problem that the PSF intensity that directly affects the quality of the output image of the SS-OCT apparatus is lowered. The wavelength swept light source of the present invention maintains the coherence length of the output light in a long state over the entire swept wavelength band. Corresponding to the wavelength sweep, the gain of the gain medium is changed with time, and the coherence length is maintained at the maximum state. The gain of the gain medium is maintained in the vicinity of the oscillation threshold over the entire sweep wavelength band, and the unsaturated gain bandwidth of the gain medium is narrowed. An SOA current waveform data acquisition method for driving while maintaining the coherence length in a long state, a novel coherence length measurement method, and an optical deflector suitable for a wavelength swept light source are also disclosed.