A method for producing an optical fiber, said method comprising: drawing the fiber from a heated glass source at a draw rate of at least 10 m/s, treating the optical fiber by maintaining the optical fiber in a treatment zone while subjecting the optical fiber to an average cooling rate in the treatment zone defined as a fiber entry surface temperature minus a fiber exit surface temperature divided by the total residence time of the optical fiber in the treatment zone of less than 5,000 °C./s, wherein the surface temperature of the optical fiber exiting the treatment zone is at least 1,000 °C; and wherein the steps of drawing the fiber from a heated glass source and treating the fiber in a treatment zone occur along a first pathway characterised in that the method further comprises: contacting the bare optical fiber with a region of fluid in a fluid bearing, said fluid bearing comprising a channel, said channel defined by at least two sidewalls (242,244), the fiber being retained within a region of said channel which is sufficient to cause said fiber to be levitated within the channel substantially as a result of a pressure differential which is present below the fiber within the channel, said pressure differential caused by a higher pressure caused by said fluid being supplied below the fiber within the channel compared to the pressure which is present above the fiber, and redirecting the fiber along a second pathway as said bare optical fiber is drawn across said region of fluid cushion; wherein the length of the treatment zone is at least 5 meters. drawing the fiber from a heated glass source at a draw rate of at least 10 m/s, treating the optical fiber by maintaining the optical fiber in a treatment zone while subjecting the optical fiber to an average cooling rate in the treatment zone defined as a fiber entry surface temperature minus a fiber exit surface temperature divided by the total residence time of the optical fiber in the treatment zone of less than 5,000 °C./s, wherein the surface temperature of the optical fiber exiting the treatment zone is at least 1,000 °C; and wherein the steps of drawing the fiber from a heated glass source and treating the fiber in a treatment zone occur along a first pathway characterised in that the method further comprises: contacting the bare optical fiber with a region of fluid in a fluid bearing, said fluid bearing comprising a channel, said channel defined by at least two sidewalls (242,244), the fiber being retained within a region of said channel which is sufficient to cause said fiber to be levitated within the channel substantially as a result of a pressure differential which is present below the fiber within the channel, said pressure differential caused by a higher pressure caused by said fluid being supplied below the fiber within the channel compared to the pressure which is present above the fiber, and redirecting the fiber along a second pathway as said bare optical fiber is drawn across said region of fluid cushion; wherein the length of the treatment zone is at least 5 meters. contacting the bare optical fiber with a region of fluid in a fluid bearing, said fluid bearing comprising a channel, said channel defined by at least two sidewalls (242,244), the fiber being retained within a region of said channel which is sufficient to cause said fiber to be levitated within the channel substantially as a result of a pressure differential which is present below the fiber within the channel, said pressure differential caused by a higher pressure caused by said fluid being supplied below the fiber within the channel compared to the pressure which is present above the fiber, and redirecting the fiber along a second pathway as said bare optical fiber is drawn across said region of fluid cushion; wherein the length of the treatment zone is at least 5 meters.