An optical fiber comprising: (i) a central core having a relative refractive index delta _C; (ii) a multi-pedestal region in contact with and surrounding the core, said multi-pedestal region having an outer radius of less than 25 m and at least two pedestals, each of the pedestals being in contact and adjacent to at least one other pedestal, each of the pedestals having a relative refractive index _ped lower than _C, at least one of the pedestals having _ped value higher than 0.2%; and (iii) another region in contact and surrounding the multi-pedestal region, the other region having a relative refractive index delta which is lower than that of any pedestal.