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Optical Fibers and Amplifiers for WDM Systems
MICHAEL J. YADLOWSKY,
MEMBER, IEEE,
EVELYN M. DELISO,
AND
VA L
́
ERIA L. DA SILVA,
MEMBER, IEEE
Invited Paper
The development of optical-fiber amplifiers allowed a dramatic
increase in the capacity of optical transmission systems while
reducing system costs. Capacity increases are possible because
the high output powers afforded by optical-fiber amplifiers support
higher bit rates, while their broad bandwidth and slow gain dynam-
ics allow multichannel operation. This benefit comes at the expense
of having to manage signal-to-noise ratio degradations due to
the accumulation of amplifier noise and dispersion distortions
accumulated over the total system link. Furthermore, nonlinear
optical effects become significant with the use of high power
signals over long lengths of fiber, causing cross talk among the
different channels and increasing signal distortions. To fully exploit
the potential capacity of wavelength division multiplexing systems,
the optical characteristics of the fibers and optical-fiber amplifiers
must be optimized. The optical amplifiers should have low noise
and flat gain, which can be achieved by using 980-nm pump lasers,
optimized fiber glass composition, and gain-flattening filters. The
optical fibers should have a small nonzero dispersion and large
effective area. Both features can be achieved by optimizing the
fiber index profile. This paper summarizes the state of the art in
these components and points to directions for future exploration.
Keywords—
Erbium materials/devices, optical amplifiers, optical
communication, optical communication equipment, optical distor-
tion, optical fiber amplifiers, optical fiber communication, optical
fiber dispersion, optical fibers, optical repeaters, wavelength divi-
sion multiplexing.
I. I
NTRODUCTION
Optical fibers are the medium of choice for telecommuni-
cations systems. They were first deployed by long-distance
carriers for long-haul systems but now are replacing
copper and coaxial cable in local telephone networks,
cable television networks, and local-area networks. The
widespread use of optical fibers is driven by the unique
properties of fibers: very low attenuation (0.2 dB/km),
large potential bandwidth (
1 THz in the 1550-nm band),
and low price. The full exploitation of fiber capacity is not
easy, but tremendous progress has been made over the past
20 years, during which the capacity of long-haul terrestrial
networks doubled every two years. Until recently, increased
capacity was attained through higher bit rates in which
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Optical Fibers and Amplifiers for WDM Systems
MICHAEL J. YADLOWSKY,
MEMBER, IEEE,
EVELYN M. DELISO,
AND
VA L
́
ERIA L. DA SILVA,
MEMBER, IEEE
Invited Paper
The development of optical-fiber amplifiers allowed a dramatic
increase in the capacity of optical transmission systems while
reducing system costs. Capacity increases are possible because
the high output powers afforded by optical-fiber amplifiers support
higher bit rates, while their broad bandwidth and slow gain dynam-
ics allow multichannel operation. This benefit comes at the expense
of having to manage signal-to-noise ratio degradations due to
the accumulation of amplifier noise and dispersion distortions
accumulated over the total system link. Furthermore, nonlinear
optical effects become significant with the use of high power
signals over long lengths of fiber, causing cross talk among the
different channels and increasing signal distortions. To fully exploit
the potential capacity of wavelength division multiplexing systems,
the optical characteristics of the fibers and optical-fiber amplifiers
must be optimized. The optical amplifiers should have low noise
and flat gain, which can be achieved by using 980-nm pump lasers,
optimized fiber glass composition, and gain-flattening filters. The
optical fibers should have a small nonzero dispersion and large
effective area. Both features can be achieved by optimizing the
fiber index profile. This paper summarizes the state of the art in
these components and points to directions for future exploration.
Keywords—
Erbium materials/devices, optical amplifiers, optical
communication, optical communication equipment, optical distor-
tion, optical fiber amplifiers, optical fiber communication, optical
fiber dispersion, optical fibers, optical repeaters, wavelength divi-
sion multiplexing.
I. I
NTRODUCTION
Optical fibers are the medium of choice for telecommuni-
cations systems. They were first deployed by long-distance
carriers for long-haul systems but now are replacing
copper and coaxial cable in local telephone networks,
cable television networks, and local-area networks. The
widespread use of optical fibers is driven by the unique
properties of fibers: very low attenuation (0.2 dB/km),
large potential bandwidth (
1 THz in the 1550-nm band),
and low price. The full exploitation of fiber capacity is not
easy, but tremendous progress has been made over the past
20 years, during which the capacity of long-haul terrestrial
networks doubled every two years. Until recently, increased
capacity was attained through higher bit rates in which
Do Drive thay đổi chính sách, nên một số link cũ yêu cầu duyệt download. các bạn chỉ cần làm theo hướng dẫn.
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