Patent ID: 7668211

Claim:
A gain guided index antiguided fiber laser comprising: one single gain guided index antiguiding fiber having a refractive index crossover at a wavelength between a pump wavelength and a laser emission wavelength, the fiber having a core and a cladding, the refractive index crossover condition requiring core and cladding material be selected for a refractive index of the cladding material less than the core material at the wavelength of optical pumping radiation and the refractive index of the core material being less than the refractive index of the cladding material at the laser emission wavelength; and a pumping system to produce a pump light having a pump wavelength, the pump light pumped into the refractive index crossover gain guided-index antiguided fiber, wherein the refractive indices of the core material and cladding material of the one single gain guided index antiguiding fiber are selected so that the laser light at the laser emission wavelength is guided by the gain guiding process in the core and the pump light at the pump wavelength that is different than the laser emission wavelength propagating in the fiber is effectively coupled into the core via an index guiding process.