1,694 research outputs found
On Time-Bandwidth Product of Multi-Soliton Pulses
Multi-soliton pulses are potential candidates for fiber optical transmission
where the information is modulated and recovered in the so-called nonlinear
Fourier domain. While this is an elegant technique to account for the channel
nonlinearity, the obtained spectral efficiency, so far, is not competitive with
the classic Nyquist-based schemes. In this paper, we study the evolution of the
time-bandwidth product of multi-solitons as they propagate along the optical
fiber. For second and third order soliton pulses, we numerically optimize the
pulse shapes to achieve the smallest time-bandwidth product when the phase of
the spectral amplitudes is used for modulation. Moreover, we analytically
estimate the pulse-duration and bandwidth of multi-solitons in some practically
important cases. Those estimations enable us to approximate the time-bandwidth
product for higher order solitons.Comment: Accepted for ISIT 201
Information Transmission using the Nonlinear Fourier Transform, Part III: Spectrum Modulation
Motivated by the looming "capacity crunch" in fiber-optic networks,
information transmission over such systems is revisited. Among numerous
distortions, inter-channel interference in multiuser wavelength-division
multiplexing (WDM) is identified as the seemingly intractable factor limiting
the achievable rate at high launch power. However, this distortion and similar
ones arising from nonlinearity are primarily due to the use of methods suited
for linear systems, namely WDM and linear pulse-train transmission, for the
nonlinear optical channel. Exploiting the integrability of the nonlinear
Schr\"odinger (NLS) equation, a nonlinear frequency-division multiplexing
(NFDM) scheme is presented, which directly modulates non-interacting signal
degrees-of-freedom under NLS propagation. The main distinction between this and
previous methods is that NFDM is able to cope with the nonlinearity, and thus,
as the the signal power or transmission distance is increased, the new method
does not suffer from the deterministic cross-talk between signal components
which has degraded the performance of previous approaches. In this paper,
emphasis is placed on modulation of the discrete component of the nonlinear
Fourier transform of the signal and some simple examples of achievable spectral
efficiencies are provided.Comment: Updated version of IEEE Transactions on Information Theory, vol. 60,
no. 7, pp. 4346--4369, July, 201
Vector Dissipative Solitons in Graphene Mode Locked Fiber Lasers
Vector soliton operation of erbium-doped fiber lasers mode locked with atomic
layer graphene was experimentally investigated. Either the polarization
rotation or polarization locked vector dissipative solitons were experimentally
obtained in a dispersion-managed cavity fiber laser with large net cavity
dispersion, while in the anomalous dispersion cavity fiber laser, the phase
locked NLSE solitons and induced NLSE soliton were experimentally observed. The
vector soliton operation of the fiber lasers unambiguously confirms the
polarization insensitive saturable absorption of the atomic layer graphene when
the light is incident perpendicular to its 2D atomic layer
Large energy soliton erbium-doped fiber laser with a graphene-polymer composite mode locker
Due to its unique electronic property and the Pauli Blocking Principle,
atomic layer graphene possesses wavelength-independent ultrafast saturable
absorption, which can be exploited for the ultrafast photonics application.
Through chemical functionalization, a graphene-polymer nanocomposite membrane
was fabricated and firstly used to mode lock a fiber laser. Stable mode locked
solitons with 3 nJ pulse energy, 700 fs pulse width at the 1590 nm wavelength
have been directly generated from the laser. We show that graphene-polymer
nanocomposites could be an attractive saturable absorber for high power fiber
laser mode locking.Comment: Large energy soliton erbium-doped fiber laser with a graphene-polymer
composite mode locker. Applied Physics Letters, Accepte
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