OPTICAL DEVICE

摘要

An optical device comprises a substrate (310) having at least one light-guiding core (320) and cladding material (330) surrounding the core; a cladding-modifying element (340) disposed alongside, at least in part, a portion of the light-guiding core, the cladding-modifying element being formed of a material different to the cladding material so that the refractive index difference between the material of the cladding-modifying element and the cladding material is dependent upon the temperature of the cladding-modifying element; and a heating and/or cooling arrangement for altering the temperature of the cladding-modifying element. A portion of the light-guiding core (320) is narrowed.