Rare earth-doped fiber optic device for emitting or amplifying a signal in the “S” band

A device comprising:

• a photonic band gap optical fiber including a solid core made up of a rare earth-doped silica glass with a refraction index of nc, surrounded by an optical cladding including N pairs of silica layers around the core, in which N is a whole number greater than 2, each pair being made up of a first inner layer of silica, the first inner layer having a thickness di, and a refraction index ni, the refraction index ni of the first inner layer being greater than the refraction index nc of the core, the first inner layer being covered by a second outer layer in contact with the first inner layer, the second outer layer being made of silica, the second outer layer having a thickness de and a refraction index ne, the refraction index ne of the second outer layer being less than the refraction index ni of the first inner layer, the photonic band gap optical fiber configured to create signal propagation losses in order to attenuate signals within C and L bands which enables amplification of at least one signal within an S band over the entire length of the photonic band gap optical fiber.