Pirelli Cavi E Sistemi S.p.a.

Pirelli & C. S. P. A.

Pirelli S.p.a.

Prysmian S.p.a.

Bartolomeo Italo Tirloni

Giacomo Stefano Roba

Davide Sarchi

Francesco Sartori

A half-dispersion-shifted single mode optical transmission fiber (HDSF) having a core and a cladding. The core has an inner core with a first refractive-index difference and a first glass layer surrounding the inner core and having a second refractive-index difference. The HDSF fiber has a peak refractive index difference of less than or equal to about 0.0140, a zero-dispersion wavelength greater than 1450 nm and lower than 1500 nm, a dispersion value of between about 6 and 11 ps/nm/km at an operating wavelength of about 1560 nm and an effective area of at least 60 &#x3bc;m. The cabled HDSF fiber has cutoff wavelength of less than about 1500 nm. An optical transmission line having a first span including at least one single-mode fiber having a negative dispersion at an operating wavelength and a second span coupling to the first span, the second span having at least one HDSF fiber, the positive dispersion of the second span compensating the negative dispersion of the first span such that the cumulative dispersion across the first and second spans is approximately zero.

Optical fiber for WDM transmission

An optical fiber transmission link has a first optical fiber with a high effective area coupled to a second, downstream optical fiber with a low effective area. The downstream fiber has non-zero dispersion and low dispersion slope. Characteristics of the upstream fiber permit the launching of high power channels in a wavelength division multiplexing, and characteristics of the downstream fiber enable Raman amplification along that fiber to extend the transmission distance before a need for discrete amplification. The downstream fiber has a non-zero dispersion in the C-band wavelengths and a low dispersion slope and has low attenuation at the signal and pump wavelengths. Refractive-index profiles include variations of W-type fibers that may include outer rings of positive or negative index. Pumping of the downstream fiber may occur either co-directionally to the signals, counter-directionally to the signals, or in both directions.

Optical transmission link with low slope, raman amplified fiber

An optical transmission fiber has a refractive index profile with an area of increased index of refraction at the inner core of the fiber, an annular region positioned radially outward from the inner core with an index of refraction exceeding the index of the inner core, and at least a low dopant content region in a cross-sectional region between the inner core and the annular region. A low loss cladding layer surrounds the core region. The optical transmission fiber with this segmented core profile provides a high effective area, low non-linearity coefficient, nonzero dispersion, and relatively flat dispersion slope.

Optical fiber having low non-linearity for WDM transmission

An optical transmission fiber for use in a wavelength division multiplexing transmission system is disclosed. The transmission fiber includes an inner core surrounded by a first, second and at least a third glass layer along the length of the fiber. The first glass layer has a depressed refractive-index difference and the second glass layer has a refractive-index difference of substantially zero. The third glass layer has a positive refractive-index difference. The fiber has an improved relationship between dispersion slope and depressed profile volume. The fiber can have a dispersion value of at least 1.5 ps/nm/km and a dispersion slope of less than about 0.07 ps/nm/km over an extended range of carrier wavelengths for the transmission system, such as the range 1450-1650 nm.

Optical fiber for extended wavelength band

An optical transmission fiber for use in a wavelength division multiplexing transmission system is disclosed. The transmission fiber includes an inner core surrounded by a first, second and at least a third glass layer along the length of the fiber. The first glass layer has a depressed refractive-index difference and the second glass layer has a refractive-index difference of substantially zero. The third glass layer has a positive refractive-index difference. The fiber has an improved relationship between dispersion slope and depressed profile volume. The fiber can have a dispersion value of at least 1.5 ps/nm/km and a dispersion slope of less than about 0.07 ps/nm /km over an extended range of carrier wavelengths for the transmission system, such as the range 1450-1650 nm.

An apparatus and method for transmitting an optical signal. The invention is directed to a transmission line having first ( ) and second ( ) spans of single mode fiber. The fiber of the first span has a negative dispersion with an absolute value of between about 2.5 ps/nm/km and 10 ps/nm/km at the operating wavelength. The second span ( ) is connected to the first span ( ) and has a positive dispersion at the operating wavelength. The positive dispersion of the second span compensates for the negative dispersion of the first span such that the cumulative dispersion across the first and second spans is approximately zero. The increased dispersion of the first span coincides with characteristics to lower non-linear effects, permits a longer length of the second span, and helps lower attenuation in the transmission line.

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Bergamo, Italy

Bartolomeo Italo Tirloni