REFRACTIVE INDEX MEASURING METHOD AND REFRACTIVE INDEX MEASURING DEVICE

摘要

PROBLEM TO BE SOLVED: To readily measure at high accuracy a refractive index of a liquid at a near infrared by auxiliarily providing a waveguide passage interferometer having a groove, of which a light passage length is increased or decreased by a constant quantity on a plurality of waveguide passages. SOLUTION: A wedge-shaped groove 30 is provided on a plurality of array waveguide passages 23. The groove 30 has a form, in which a light passage length (groove width) in the groove is increased, by a constant quantity (δ1) with respect to a direction that a length of each array waveguide passage 23 is increased. An output light from a light source 40 is inputted to an input waveguide passage 21 of an array waveguide lattice type wavelength wave distributor (AWG) 20 through an optical fiber 41. A light inputted through an input waveguide passage 21 and passed through the array waveguide passage 23, a slab waveguide passage 24 and an output waveguide passage 25 is made incident to a spectrum analyzer 50 which calculates a refractive index of a liquid to be measured by measuring a wavelength of a light when the groove 30 is hollow and the liquid to be measured is filled in the groove 30.