Optical adjustment apparatus, optical adjustment method, and optical device

An optical adjustment apparatus includes a measurement-light irradiation part that has a plurality of second optical fibers and emits, with timings different from each other, a plurality of lights having a single wavelength via the second optical fibers, an optical fiber block that holds exit-side end portions of the first and second optical fibers, a light detection part that receives and detects a plurality of reflected lights via the second optical fibers, a tilt calculation part that compares, with each other, variations with time of intensities of the respective reflected lights and calculates a tilt of the optical fiber block relative to the optical substrate, and a distance calculation part that calculates an inter-end surface distance between the optical substrate and the optical fiber block, based on a variation with time of an intensity of at least one reflected light.