ABSTRACT
We present the design and characterization of a cladding-pumped amplifier with erbium doping located in an annular region near the core. This erbium-doped fiber is proposed to reduce gain saturation, leading to smaller gain compression when compared to uniform core doping. Through numerical simulations, we first compare the performance of three fibers with different erbium doping profiles in the core or the cladding. When the doped fibers are operated at the optimum length, results show that the smaller overlap of the signal mode field with the annular erbium doping region leads to higher gain and lower saturation of the amplifier. A single-core erbium-doped fiber with an annular doping and a D-shaped cladding was fabricated. Measurements demonstrate less than 4 dB of gain compression over the C-band for input power ranging from -40 dBm to 3 dBm. Small gain compression EDFAs are of interest for applications that require input channel reconfiguration. Higher gain and saturation output power are also key issues in cladding-pumped multi-core amplifiers.
ABSTRACT
Permanent grating patterns have been written directly in lead-tin-fluorophosphate glasses by use of UV radiation. The effect of photorefraction is studied in different tin-fluorophosphate compositions. Recorded gratings are found to be volume rather than surface elements. The induced index changes are comparable with those seen in GeO(2)- SiO(2) glasses.
ABSTRACT
In Ref. 1, owing to an editorial error, the acronym EDDF was defined as electronic data display fiber.This expression should be replaced with exponentially dispersion-decreasing fiber throughout the text [after Eq. (5)].
ABSTRACT
We study analytically and numerically soliton communication links made by use of dispersion-decreasing fibers and parametric amplif iers. We show that bit rates greater than 100 Gbits/s (one channel, one polarization) can be achieved with large amplif ier spacings (as high as 120 km). The Raman effect and soliton interactions are compensated through optical phase conjugation, whereas fiber losses and third-order dispersion are handled through tailoring of the dispersion profile of a dispersion-decreasing fiber.
ABSTRACT
We show analytically that tailoring the fiber dispersion appropriately can cause optical solitons to propagate unperturbed, without emission of dispersive waves, in a distributed-gain fiber amplifier with a nonuniform gain profile. We apply our scheme to a bidirectionally pumped fiber amplifier and discuss the importance of higher-order nonlinear and dispersive effects for short solitons.
ABSTRACT
We numerically demonstrate soliton transmission over long distances in a new regime in which the soliton evolves in a two-core fiber over many dispersion lengths between successive amplifications. Shorter pulses than those transmitted in the average soliton dynamics regime are predicted, while a significant drift of the soliton mean frequency owing to the soliton self-frequency shift is observed and controlled by appropriate gain and loss parameters.
