An optical fiber includes a core and a cladding, said cladding having a refractive index nc a first coating directly contacting the cladding of said fiber, said coating having a thickness of less than 10 microns, said coating having a refractive index delta %=100×(ni2−nc2)/2ni2 less than −1 percent. In another aspect, an optical fiber includes a core and a cladding, said cladding having a refractive index nc, a first coating directly contacting the cladding of said fiber, said fiber comprising a glass diameter less than 100 microns, said coating having a thickness of at least 8 microns, said coating having a refractive index delta %=100×(ni2−nc2)/2ni2 less than −1 percent.