Length Of Erbium-doped Fiber Research Articles

A theoretical analysis of amplification characteristics of bi-directional erbium-doped fiber amplifiers with single erbium-doped fiber

Based on the discussion of the structure scheme of bi-directional EDFA (Bi-EDFA) with single erbium-doped fiber (EDF) which can efficiently suppress the internal reflections, a rate equation model for the Bi-EDFA is developed to calculate the signal gain, pump absorption and output noise spectrum. The effects of numbers of signals, pumps of arbitrary direction, amplified spontaneous emission (ASE) and inherent loss are taken into account. Using this model, the influence of EDF length, input signal power, pump style and pump power on the gain characteristics of the Bi-EDFA is analyzed. The forward and the backward noise figures versus bi-directional input signal power for different pump styles are also investigated. With these results, the optimal design for Bi-EDFAs in optical fiber communication systems and networks can be achieved.

Emission Dependence on Length in a 1.48-mum Pumped Erbium-Doped Laser with an All-Fiber Configuration

We report a study on the main features of a 1.48-mum pumped erbium-doped fiber laser, such as threshold pump power, output power, and slope efficiency. In particular we have focused on its dependence on active fiber length. We employed an all-fiber laser configuration, which included mirrors directly coated onto the polished fiber endfaces. Launched pump power and laser output power were introduced and extracted, respectively, from the laser cavity by means of couplers. Our measure ments show the existence of an optimum erbium-doped fiber length, where threshold power reaches minimum and output power maximum.

A detailed comparison of the overall performance of 980 and 1480 nm pumped EDFA cascades in WDM multiple-access lightwave networks

A detailed comparison of the overall performance of 980 and 1480 mn pumped Er-doped fiber amplifier cascades over four different spectral regions of the usable amplifier band for multiple wavelength operation is presented. These comparisons are carried out by presenting a simple optimization method that relates the individual amplifier performance parameters to the overall performance of an amplifier cascade for best overall system performance. Issues considered are pump power, erbium-doped fiber length, accumulated ASE, inversion level, inter-amplifier fiber loss, and input signal levels and their spectral range.

THEORETICAL STUDY ON OUTPUT CHARACTERISTICS OF Er3+-DOPED FIBER RING LASERS

A theoretical model has been established based on the solution of the rate equations for the erbium-doped fiber ring laser(EDFL). Analytic solutions for the threshold pump power, the output power, the slope efficiency and optimum erbium-doped fiber length of EDFL are obtained. The physical explanations have been given for the results.

Performance of erbium-doped fiber amplifier cascades in WDM multiple access lightwave networks

A simple method to optimize individual EDFA performance parameters for multiwavelength operation in an amplifier cascade is presented. The pump power, pump wavelength, erbium-doped fiber length, and input signal levels and their spectral range are each optimized. We find that 980-nm pumping, together with an optimum amplifier length of 9 m, provides adequate performance for six 10 Gb/s WDM channels to be transmitted through a cascade of 27 amplifiers, allowing a total system gain of more than 350 dB without requiring gain equalization methods. >

Gain peak wavelength measurements using a polarization scrambled fiber loop configuration

We present a quick and accurate method to measure the gain peak wavelength (GPW) of concatenated optical amplifiers in a long haul optical fiber communication system. This method utilizes a simple fiber-amplifier loop with polarization scrambling. We verify that the GPW of an amplifier is completely determined by the operating gain per unit erbium doped fiber length and changes linearly with compressed gain near 1.558 μm. The data presented, indicates how the GPW can be controlled for a broad range of operating gains by adjusting the erbium fiber length. The temperature and pump power dependence of GPW were found to be negligible for typical undersea system amplifier conditions. The gain bandwidth for concatenated amplifier systems appears to be a function of compression not operating gain, implying that wavelength division multiplexing systems requiring a flattened gain response should take this into consideration.

Narrow-linewidth, singlemode erbium-doped fibrelaser with intracavity wave mixing in saturableabsorber

Narrow-linewidth, single longitudinal mode operation is demonstrated in an erbium-doped fibre laser with an intracavity nonlinear absorptive wave mixing of the counterpropagating beams. An unpumped length of erbium-doped fibre serves as the saturable absorber. Linewidths of the order of a few kilohertz are obtained.

Attenuation and fluorescence characteristics of optical signals propagating in an erbium-doped fiber

For a monochromatic input signal launched into an erbium-doped fiber (EDF), a broadband fluorescence spectrum will be generated with total power approximately 30 dB lower than input signal power. The forward fluorescence power decays slowly at long EDF length due to smaller absorption cross section for wavelength components away from absorption peak. Care must be taken when the conventional cutback method is used to measure the attenuation of the optical signals in an EDF. The backward fluorescence power is saturated to a constant level, and the spectrum does not change for long EDF.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Laser-diode-pumped nonlinear switch in erbium-doped fiber

We describe a two-mode fiber switch made of a short length of erbium-doped fiber in which switching is accomplished by a nonlinearity that is resonantly enhanced by the dopant. In a 0.95-m fiber pumped with a 1.48-μm laser diode, a 906-nm signal is switched with only 8 mW of absorbed power at a signal absorption loss of 0.25 dB.