Abstract: Described herein is a method for making a depressed index cladding for the inner cladding of an optical fiber. The method involves making the depressed index cladding in two steps. The innermost portion of the inner cladding is produced using a soot method, thereby deriving the advantages of the soot method for the region of the cladding that carries the most optical power, then forming the remaining portion of the inner cladding layer using a rod-in-tube step. This method effectively marries the advantages and disadvantages of both methods.

Abstract: Described herein is a method for making a depressed index cladding for the inner cladding of an optical fiber. The method involves making the depressed index cladding in two steps. The innermost portion of the inner cladding is produced using a soot method, thereby deriving the advantages of the soot method for the region of the cladding that carries the most optical power, then forming the remaining portion of the inner cladding layer using a rod-in-tube step. This method effectively marries the advantages and disadvantages of both methods.

Abstract: The specification describes an improved optical fiber produced by a hybrid VAD/MCVD process. The core of the fiber is produced using VAD and the inner cladding layer has a depressed index and is produced using MCVD. In preferred embodiments, the optical power envelope is essentially entirely contained in VAD produced core material and the MCVD produced depressed index cladding material. Optical loss is minimized by confining most of the optical power to the VAD core where OH presence is low, as well as by maximizing the optical power in the un-doped silica region. The MCVD substrate tube material is essentially devoid of optical power.

Abstract: The specification describes a method for addressing defects in the center of the core of an optical fiber that are formed during high temperature steps associated with collapsing a hollow core fabricated by the MCVD, PCVD, or OVD methods. These defects form absorption centers and impair the optical transmission properties of the optical fiber. The defects are reduced or eliminated according to the invention by forming a buffer layer as the last deposited layer before collapse. The buffer layer is undoped, or lightly doped, and provides a diffusion barrier to prevent or slow a change in the oxide glass stoichiometry. The result is that fewer dopant and oxygen atoms exit from the core layers through the free surface during collapse, resulting in fewer defects and lower fiber attenuation.

Abstract: The specification describes an improved optical fiber design in which the criteria for high performance in a Raman amplified optical system, such as moderate effective area, moderate dispersion, low dispersion slope, and selected zero dispersion wavelength, are simultaneously optimized. In preferred embodiments of the invention, the dispersion characteristics are deliberately made selectively dependent on the core radius. This allows manufacturing variability in the dispersion properties, introduced in the core-making process, to be mitigated during subsequent processing steps.

Abstract: An improved optical fiber design has been found to exhibit a relatively low attenuation at the wavelength of 1385 nm (the “water peak”), allowing for Raman amplification to be efficient and effective at wavelengths in the S-band range of 1460 to 1530 nm. An ultra-dry process is used to mate an inner core rod (core plus surrounding trench) with a cladding tube (ring region plus cladding layers) and provide a water peak loss on the order of 0.325 dB/km. The low water peak is combined with appropriate dispersion values and zero dispersion wavelength to form a fiber that supports transmission and Raman amplification in the S-, C- and L-bands of interest for optical transmission systems.

Abstract: An inverse dispersion fiber having a large effective area and a transmission system that incorporates the fiber for providing dispersion and dispersion slope compensation in a transmission fiber. The large-effective-area inverse dispersion optical fiber (IDF) has a negative dispersion and a negative dispersion slope. The effective area, Aeff, of the IDF preferably is greater than approximately 31 micrometers squared (&mgr;m2) at a transmission wavelength of approximately 1550 nm. The large-effective-area IDF is suitable for use with super-large-effective-area (SLA) transmission fiber for compensating dispersion in the SLA transmission fiber while reducing nonlinear effects between wavelength channels and cabling loss, which is especially advantageous in transoceanic and long-haul terrestrial systems. These nonlinear effects are inversely related to the effective area of the fiber (i.e., nonlinearities ˜1/Aeff).

Abstract: The specification describes an improved optical fiber design in which the criteria for high performance in a Raman amplified optical system, such as moderate effective area, moderate dispersion, low dispersion slope, and selected zero dispersion wavelength, are simultaneously optimized. In preferred embodiments of the invention, the dispersion characteristics are deliberately made selectively dependent on the core radius. This allows manufacturing variability in the dispersion properties, introduced in the core-making process, to be mitigated during subsequent processing steps.

Abstract: The specification describes an improved optical fiber design in which the criteria for high performance in a Raman amplified optical system, such as moderate effective area, moderate dispersion, low dispersion slope, and selected zero dispersion wavelength, are simultaneously optimized. In preferred embodiments of the invention, the dispersion characteristics are deliberately made selectively dependent on the core radius. This allows manufacturing variability in the dispersion properties, introduced in the core-making process, to be mitigated during subsequent processing steps.