摘要:
An optical fiber preform (1) serving as a material of an optical fiber has a shoulder portion (12) thrusting beyond a middle portion (M) in a base end region (K) which is on the upper side when the optical fiber preform is suspended for a drawing process. The optical fiber preform (1) of this configuration can be easily produced by appropriately setting the heating condition, etc. for the sintering step in the production process. Thus, it is possible to omit the elongating step after the sintering step, thereby simplifying the production process. Further, in the prior-art technique, turbulence is generated in the gas flow in the furnace of the drawing apparatus toward the end of the drawing step, making it impossible to draw in a stable manner. In contrast, in this embodiment, due to the shoulder portion (12), there is a small gap between the inner wall surface of the furnace and the optical fiber preform; due to this small gap, the gas flow is regulated, and the drawing can be conducted in a stable manner even toward the end of the drawing step.
摘要:
An optical fiber having optical characteristics that systematically vary along its length is made by inserting a plurality of cylindrical tablets into a cladding glass tube and overcladding the tube with particles of cladding glass. Each tablet contains a core region, and it optionally contains a layer of cladding glass Adjacent tablets are capable of forming optical fiber sections having different optical properties. Prior to consolidating the glass particles, chlorine flows through the tube and over the tablets. When the tube begins to sinter, the chlorine flow is stopped and the sintering particles generate an inwardly directed force that causes the tube to collapse inwardly onto the tablets which concurrently become fused to each other. The resultant draw blank can be drawn into a low loss optical fiber. This method is particularly useful for making dispersion managed single-mode optical fibers.
摘要:
The present invention relates to an optical fiber comprising a structure enabling WDM transmissions by utilizing the whole wavelength range of 1300 nm to 1625 nm as a signal wavelength band. In the optical fiber according to the present invention, the transmission loss is 0.4 dB/km or less at a wavelength of 1310 nm, 0.4 dB/km or less at a wavelength of 1383 nm, and 0.3 dB/km or less at a wavelength of 1550 nm. The chromatic dispersion is 0.1 ps/nm/km or more but 5.5 ps/nm/km or less at a wavelength of 1383 nm, and 0.1 ps/nm/km or more but 16.5 ps/nm/km or less in the wavelength range of 1530 nm to 1565 nm. The cut off wavelength at a length of 22 m is 1300 nm or less, and the absolute value of dispersion slope in the wavelength range of 1300 nm to 1625 nm is 0.1 ps/nm2/km or less.
摘要:
There are disclosed a method for producing an optical fiber base material ingot comprising depositing a soot on a starting core member, and subjecting the soot to dehydration, vitrification by sintering, and then cylindrical grinding, wherein the cylindrical grinding is performed while a core portion central axis is brought into line with a rotation axis of cylindrical grinding machine, and an optical fiber base material ingot produced by the method. According to the present invention, there are provided an optical fiber base material ingot having excellent ingot roundness and excellent core portion eccentricity, and a production method capable of producing the optical fiber base material ingot in a short period of time.
摘要:
In an optical fiber of this invention, the MFD is increased to effectively suppress the influence of nonlinear optical effects. A method of manufacturing the optical fiber effectively prevents bubble occurrence in a transparent preform, deformation of the preform, and flaws on the preform surface during the manufacture. The optical fiber has, from its center to the peripheral portion, a first core having a first refractive index n1, a second core having a second refractive index n2 ( n3,
摘要:
A sintered dense glass, alumina-doped optical fiber preform is stretched and is then heated to a temperature of 1490-1495° C. to remove bubbles without causing crystallization. Thereafter, the stretched glass body is either drawn directly into an optical fiber or overclad and then drawn into a fiber.
摘要:
An optical fiber having optical characteristics that vary along its length is made by assembling a plurality of cylindrical glass or soot tablets into or along a glass tablet alignment device, then fused into monolithic assembly. If desired, additional glass may be applied to the assembly before or after the fusing step. A vacuum is preferably applied during the fusing step. Each tablet preferably contains a core region, and it optionally contains a layer of cladding glass. Adjacent tablets are capable of forming optical fiber sections having different optical properties. Prior to consolidating the glass particles, chlorine preferably flows through or around the tablets and alignment device. The resultant draw blank can be drawn into a low loss optical fiber having short transition regions between adjacent areas of fiber. This method is particularly useful for making dispersion managed single-mode optical fibers.
摘要:
A method for drawing a glass ingot into a rod having a given outer diameter is described. The method is characterized in that when the glass ingot is fed into a heating zone at a final tapered portion thereof, a temperature in the heating zone is decreased so that the final tapered portion is prevented from being drawn in excess owing to the heat from the heating zone.
摘要:
The present invention aims to provide a dispersion-shifted fiber which can effectively restrain nonlinear optical effects from occurring and has a configuration suitable for long-haul light transmission. The dispersion-shifted fiber has, as various characteristics at a wavelength of 1,550 nm, a dispersion level of 1.0 to 4.5 ps/nm/km in terms of absolute value, a dispersion slope not greater than 0.13 ps/nm.sup.2 /km in terms of absolute value, an effective core cross-sectional area not less than 70 .mu.m.sup.2, and a transmission loss not greater than 0.25 dB/km with respect to light in a 1.55-.mu.m wavelength band.
摘要:
A dispersion compensating fiber is provided which is capable of reducing the birefringence of the core caused in spinning to suppress an increase in polarization mode dispersion due to the birefringence of the core even though the surface of the core rod is ground to shape the profile of the core during manufacturing. A silica glass cladding 2 doped with fluorine is disposed to surround a silica glass core 1 doped with germanium. The variation in circumferential concentration of germanium at the periphery of the core 1 is set at 0.05% or smaller in relative refractive index difference value.