Patent ID: 7505655

Claim:
A white light-emitting device using a fluorescent fiber, comprising: a blue semiconductor light-emitting element for emitting an excitation light; and an optical fiber having a first side end face and a second side end face, the excitation light emitted from the blue semiconductor light-emitting element being made incident to the first side end face to be guided to the second side end face, the optical fiber comprising: a core including a low phonon glass containing therein at least praseodymium ions, as trivalent rare earth ions, for emitting wavelength conversion lights by being excited by the excitation light; and a cladding member having a light emission surface in its peripheral surface, at least a part of optically multiplexed lights, which are obtained by optically multiplexing the wavelength conversion lights and the excitation light, being emitted through the light emission surface, wherein the cladding member of the optical fiber includes a first cladding member formed adjacently to a peripheral surface of the core, and a second cladding member formed adjacently to a peripheral surface of the first cladding member, and a refractive index of the first cladding member is set to one that is smaller than that of the core, but is larger than that of the second cladding member.