An optical fiber production system includes an annealing furnace having a furnace inlet, a furnace outlet, and a process tube extending between the furnace inlet and the furnace outlet, the process tube having a process tube wall and a heating zone including at least one heating element. The optical fiber production system also includes a gas distribution assembly fluidly coupled to the furnace outlet and structurally configured to induce gas flow from the gas distribution assembly into the process tube such that gas flows within the process tube in an upflow direction.

An optical fiber production method includes: drawing an optical fiber from an optical fiber preform; and cooling the optical fiber. When in the cooling process, the optical fiber is passed through a plurality of annealing furnaces and Equation (1) is held. A time constant of relaxation of a structure of glass forming a core in the optical fiber is (T.sub.n). A temperature of the optical fiber at a point in time when the optical fiber is delivered into an nth annealing furnace from an upstream side is T.sub.n. A fictive temperature of glass forming the core at the point in time when the optical fiber is delivered is T.sub.fn. A fictive temperature of glass forming the core after a lapse of time t from the point in time when the optical fiber is delivered is T.sub.f.

20 C.<T.sub.fT.sub.n=(T.sub.fnT.sub.n)exp(t/T(T.sub.n))<100 C.(1)

A method for producing an optical fiber includes heating and melting an optical fiber preform and drawing the optical fiber preform. In this method for producing an optical fiber, the optical fiber is formed to include a core, a surrounding cladding surrounding a periphery of the core, and an outer cladding surrounding the surrounding cladding. In the drawn optical fiber, a maximum compressive stress of at least 100 MPa or more is applied to an optical waveguide region including at least the core.

There is provided a method for producing a low-loss alkali metal-doped silica core optical fiber having excellent hydrogen resistance. The method for producing the optical fiber according to the present invention includes a drawing step of drawing an optical fiber preform in a drawing furnace to produce a silica glass-based optical fiber including a core region containing an alkali metal with an average concentration of 0.5 atomic ppm or more and a cladding region that surrounds the core region and a heating step of heating the optical fiber in a heating furnace through which the optical fiber drawn from the drawing furnace passes.

According to some embodiments a method of processing an optical fiber comprises the steps of: (i) drawing the fiber at a drawing rate of at least 30 m/sec; and (ii) cooling the drawn fiber in a gas at an average cooling rate less than 5000 C./s, such that said cooling reduces the temperature of the fiber from an entering temperature in the range between 1500 C. and 1700 C. to another temperature in the range between 1200 C. and 1400 C., the gas being at a temperature between 800 C. and 1500 C.; and the thermal conductivity of the gas being not greater than 1.510.sup.4 cal/cm-s-K for at least one temperature within a range of 800 C. to 1500 C. at one atm (atmosphere) pressure absolute.

A portable computing device includes a processor, a memory, and a portable computing device case that encloses one or more integrated circuits, including at least the processor and the memory. The case includes a molded fiber-reinforced polymer (FRP) material that includes a polymer material and elongated fibers that adhere to the polymer material and that have a property that varies over a length of the fibers along an elongation axis of the fibers, wherein an adhesion strength between the fibers and the polymer is determined at least in part by a property of the fibers that varies over a length of the fibers along the elongation axis.

A single mode optical fiber having a core made from silica and less than or equal to about 6.5 weight % germania and having a maximum relative refractive index .sub.1MAX. The optical fiber also has an inner cladding surrounding the core and having a minimum relative refractive index .sub.2MIN. A difference between a softening point of the core and a softening point of the inner cladding is less than or equal to about 20 C., and .sub.1MAX>.sub.2MIN. The single mode optical fiber may also have an outer cladding surrounding the inner cladding made from silica or SiON. The outer cladding has a maximum relative refractive index .sub.3MAX, and .sub.3MAX>.sub.2MIN. A method for manufacturing an optical fiber includes providing a preform to a first furnace, the preform, drawing the optical fiber from the preform, and cooling the drawn optical fiber in a second furnace.

There is provided a manufacturing method for an optical fiber that easily reduces transmission losses in the optical fiber. The method includes a drawing process P1 of drawing an optical fiber from an optical fiber preform 1P in a drawing furnace 110; and a slow cooling process P3 of slowly cooling the optical fiber having been drawn in the drawing process P1 in an annealing furnace 121. The temperature of the optical fiber to be delivered into the annealing furnace 121 is a temperature of 1,300 C. or more and 1,650 C. or less. The temperature of the optical fiber to be delivered out of the annealing furnace 121 is a temperature of 1,150 C. or more and 1,400 C. less.

A single mode optical fiber having a core made from silica and less than or equal to about 6.5 weight % germania and having a maximum relative refractive index .sub.1MAX. The optical fiber also has an inner cladding surrounding the core and having a minimum relative refractive index .sub.2MIN. A difference between a softening point of the core and a softening point of the inner cladding is less than or equal to about 20 C., and .sub.1MAX>.sub.2MIN. The single mode optical fiber may also have an outer cladding surrounding the inner cladding made from silica or SiON. The outer cladding has a maximum relative refractive index .sub.3MAX, and .sub.3MAX>.sub.2MIN. A method for manufacturing an optical fiber includes providing a preform to a first furnace, the preform, drawing the optical fiber from the preform, and cooling the drawn optical fiber in a second furnace.

A portable computing device includes a processor, a memory, and a portable computing device case that encloses one or more integrated circuits, including at least the processor and the memory. The case includes a molded fiber-reinforced polymer (FRP) material that includes a polymer material and elongated fibers that adhere to the polymer material and that have a property that varies over a length of the fibers along an elongation axis of the fibers, wherein an adhesion strength between the fibers and the polymer is determined at least in part by a property of the fibers that varies over a length of the fibers along the elongation axis.