| 摘要 |
PROBLEM TO BE SOLVED: To solve such problems that in a waveguide type variable dispersion compensator having a line symmetry structure by conventional technology, narrowing in a transmission band is theoretically unavoidable, that optical axis of an optical path of a light signal having a wavelength in a longer wavelength side of the center wavelengthλ<SB>0</SB>and of an optical path of a light signal having a wavelength in a shorter wavelength side of the center wavelength are bent at a condensed point in slab waveguide disposed on the axis of line symmetry, and that an increase in the theoretical coupling loss at a marginal wavelength is unavoidable, even when a phase difference is imparted by use of a phase modulation element. SOLUTION: A variable dispersion compensator is provided, in which two array waveguides having equal angle dispersion values are disposed in a point symmetry position and optical coupling between the two array waveguides is carried out by parallel beams in a slab waveguide that connects the two array waveguides. By coupling with parallel beams, optical coupling between the array waveguides is achieved without bending an optical path regardless to the wavelength of optical signals. Thereby, narrowing in the transmission band can be prevented. COPYRIGHT: (C)2009,JPO&INPIT |
