PHOTONIC CRYSTAL WAVEGUIDE, HOMOGENEOUS MEDIUM WAVEGUIDE, AND OPTICAL DEVICE

摘要

A photonic crystal waveguide and a homogeneous medium waveguide for enabling a steep bend and arrangement at an arbitrary angle with low propagation loss. A photonic crystal waveguide (200) has a core formed by a photonic crystal (50) having periodicity in the Y-direction. Electromagnetic wave is propagated by a band on the Brillouin zone boundary of the photonic band structure of the core. A side face of the core parallel to the Y-direction is in contact with a homogeneous medium having a refractive index of n s , and the condition of » 0 /n s >a » /(» 2 /4+a 2 ) 0.5 is satisfied when the wavelength in vacuum of the electromagnetic wave is represented by » 0 , the period of the photonic crystal is represented by a, and the period in the XZ-plane direction of the wave propagated through the core is represented by ». This condition is a minimum requirement for preventing leakage of light from the side face of the photonic crystal waveguide 200. By satisfying this condition, the wave propagated through the core can be confined by the side face when the propagation angle Æ is zero degrees.