A method and apparatus for rapidly cooling optical fiber comprising passing optical fiber through an enclosure having a flat black internal surface, the walls of said enclosure having symmetrically oriented perforations or other symmetrically oriented means of passing cryogenic gas through the walls to contact optical fiber within the enclosure, the enclosure surrounded by a gas plenum to which gas is supplied to facilitate the symmetrical passage of cryogenic gas through the walls, whereby the cryogenic gas symmetrically contacts and cools the optical fiber and also serves to cool the walls of the enclosure.