Patent ID: 8442372

Claim:
A microstructured optical fibre including a core surrounded by a cladding, the cladding comprising a background material having a refractive index (n1) and several inclusions of at least two different types, a first type of inclusions having a refractive index (n2) that is higher than the refractive index (n1) of the background material, and a second type of inclusions having a refractive index (n3) that is lower than the refractive index (n1) of the background material, said fibre enabling guidance by means of photonic forbidden bands of a fundamental mode of the light, characterized in that the inclusions of the cladding are arranged and dimensioned in such a way as to enable guidance by total internal reflection (RTI) of a fundamental mode of the light, centred on a wavelength λ RTI , and to enable guidance of a fundamental mode of the light in a first photonic forbidden band (BG1), centred on a wavelength λ BG1 that is lower than this wavelength λ RTI of the fundamental mode guided by total internal reflection (RTI), and wherein the wavelength λ RTI of the fundamental mode guided by total internal refection (RTI) is situated outside of the wavelength range of the fundamental mode guided in the first forbidden band (BG1).