Optical element using one-dimensional photonic crystal and spectroscopic device using the same

A spectroscopic device comprising an optical element using one-dimensional photonic crystal, including:

• a multilayer structure containing a periodic structural portion as at least one region, said periodic structural portion being regarded as a one-dimensional photonic crystal having repetition of a predetermined period, said multilayer structure having two end surfaces substantially perpendicular to layer surfaces of said multilayer structure and used as a light input surface and a light output surface respectively, wherein:
• said light output surface inclined at an inclination angle to said light input surface;
• and
• directions of propagation of input beams incident onto said light input surface, beams propagating in said multilayer structure and output beams emerging from said light output surface are perpendicular to a periodic direction of said periodic structural portion;
• a light input optical system for inputting a wavelength division multiplexing optical signal to a light input surface of said optical element, and
• a light output optical system for discriminating optical signals spectroscopically output from said optical element in accordance with wavelength.