ABSTRACT
In the present paper, the problem amplification techniques of ultra dense wavelength division multiplexing (UDWDM) in
nonlinear optical networks are investigated through five transmission techniques. The impact of tailoring of chirped
pulses of different temporal waveforms is investigated in a normal dispersion fiber. The set of multiplexed signals are
tailored in a different a subset to assure approximately the same output level of power to hold the signal-to-noise ratio at
the same level. Moreover, three different transmission techniques, namely, soliton propagation, maximum time division
multiplexing (MTDM) and ìShannonî capacity, are employed where successive section of alternating dispersion are
used as a technique to manage the dispersion. Distributed ìRamanî amplifiers as well as Erbium doped fiber amplifier
are engaged to maximize the repeater spacing. We have succeeded to multiplex 2400 (UDWDM) channels in the optical
range 1.45 1.65 µm with channel spacing ranging from 0.3 up to 0.6 nm where each channel has its own characteristic
parameters of loss, dispersion, and amplification. The channels are divided into sub-groups ( each of 4, 5, 6, 7,Ö.,24 )
where the technique of space division multiplexing (SDM) is applied. The multispan effects of ìKerrî nonlinearity and
amplifier noise on ìShannonî channel capacity of dispersion-free nonlinear fiber is considered as a ceiling value for the
sake of comparison. The case of soliton with modified Raman amplification via parametric gain also is investigated.
Each link has special chemical structure, optical signals power, and optical Raman pumping. The cable contains {4, 5, 6,
7,Ö. , 24} links in SDM. It has been shown that the modified Raman gain yields higher effects on the variable under
consideration if compared with the conventional Raman gain. The number of links is in positive correlations with the set
of effects {Repeater spacing, Soliton product, MTDM product}. In general Shannon product is the ceiling but it
undergoes a maximum value at twelve links. The Chirping product also possesses a maximum at 8 links.