Sedat Ozsoy

The temperature dependent performance analysis of EDFAs pumped at 1480 nm: A more accurate propagation equation.

An analytically expression for the temperature dependence of the signal gain of an erbium-doped fiber amplifier (EDFA) pumped at 1480 nm are theoretically obtained by solving the propagation equations with the amplified spontaneous emission (ASE). It is seen that the temperature dependence of the gain strongly depends on the distribution of population of Er3+-ions in the second level. In addition, the output pump power and the intrinsic saturation power of the signal beam are obtained as a function of the temperature. Numerical calculations are carried out for the temperature range from - 20 to + 60 oC and the various fiber lengths. But the other gain parameters, such as the pump and signal wavelengths and their powers, are taken as constants. It is shown that the gain decreases with increasing temperature within the range of L </= 27 m.

An investigation on the temperature dependence of the relative population inversion and the gain in EDFAs by the modified rate equations

Abstract The dependence of the relative population inversion in Er 3+ -doped fiber amplifiers (EDFAs) upon temperature and cross-sections, taking into account the amplified spontaneous emission (ASE), are investigated theoretically by the modified rate equation model for 980 and 1470 nm pumping conditions. For the temperature range from 0 to ±50 °C and at the different signal wavelengths, the temperature and cross section-dependent gain characteristics with respect to pump powers are also examined in detail for the both conditions. As a consequence, the dependence of the performance of EDFAs on temperature for 980 nm pumping is weaker than that for 1470 nm pumping, not only at room temperature but also at the temperature range from 0 to ±50 °C. However, the performance of EDFAs is more efficient at the pumping wavelength of 1470 nm than that of 980 nm for a wide range of temperature and higher-pump power levels. The results of this theoretical model are a good agreement with the experimental ones in the literature.

On the Temperature-Dependent Gain and Noise Figure Analysis of C-Band High-Concentration EDFAs With the Effect of Cooperative Upconversion

We present an efficient temperature-dependent analysis to study the effect of cooperative upconversion on the temperature-dependent gain (TDG) performance of the C-band erbium-doped fiber amplifier (EDFA) at high-concentration. The influence of cooperative upconversion on the TDG is examined by using a set of temperature-dependent rate and light propagation equations. In the analysis given, the amplified spontaneous emission (ASE), as well as the excited state absorption (ESA) are also considered. In the forward pumping configuration at a signal wavelength of 1547 nm and in the temperature range of - 40degC to + 80degC, the variations of the TDG and the noise figure (NF) are about 1.7 and 0.9 dB, respectively. Numerical analysis results show that, with 260-mW/1480-nm pump power, an erbium-doped fiber amplifier having a doping concentration of 4.4 times 1026 ion/m3 and optimum length of 9.2 cm may reach a signal gain of 44.6 dB and a noise figure of 3.9 dB at room temperature.

Simple equation to estimate the output power of an evanescent field absorption-based fiber sensor

The behavior of an evanescent field sensor is important for design purposes. This work gives an approximate and simple equation to estimate the absorption of light in an optical fiber with lossy cladding. The formula is based on the weakly guiding approximation and estimates the output power fraction of the sensor in terms of the fiber and the surrounding parameters. The formula is then related to the concentration of the surrounding medium.

The Effects of Complex Energy Transfer Dynamics and Gaussian Profiles on the Performance of High-Concentration EDFAs

In this paper, we investigate the effects of complex energy transfer dynamics and Gaussian profiles on the gain and noise figure performance of erbium-doped fiber amplifiers (EDFAs) with high doping concentration. We use a two-level system to study the complex energy transfer dynamics that comes from the homogeneous up-conversion (HUC) and the pair-induced quenching (PIQ). In our model, the system is stimulated by a pump source at the wavelength of 1480 nm and operated with a signal source at the wavelength of 1560 nm. Assuming a uniform distribution of erbium ions in the fiber core, we approximate the fundamental mode distributions by Gaussian profiles which are commonly used to calculate the mode radius or spot size. Using the numerical calculations and analysis of the rate and power propagation equations for a two-level model under consideration, the most advantageous Gaussian profile is determined as the Whitley mode radius to obtain a high-gain and a low-noise figure per unit length of silica-based fiber amplifiers. The effects of the number of ions per cluster and the percentage of ions in clusters on the calculated gain and noise figure are compared for several pump powers. Results are discussed to achieve a desired gain and noise figure performance, and compared with the available experimental data to verify the feasibility of the model.

The performance analysis dependent on temperature for EDFAS pumped at 1480 nm pump wavelength: a theoretical investigation

The effect of temperature on the population distribution within the manifold of an Er3+-ion pumped at 1480 nm pump wavelength is theoretically investigated. A modified rate equation model for determining the signal gain performance of EDFAs is established by including the temperature effect and the gain values versus launched pump powers at the temperature range of -20 to 60 °C are obtained under the signal power regime.

A comparison of the effect of the ellipticity on the small and large solid-core PCF’s characteristics

In this paper we study small and large solid-core PCFs with elliptical shaped air-holes for the hexagonal lattice, which were constructed by omitting one air-hole (small core) and seven air-holes (large core), respectively, and we compare their characteristics with those with circular holes. We use two types of ellipticity: vertical and horizontal. Birefringence, dispersion, and the numerical apertures of the fundamental modes are analyzed using commercial simulation software. Also, the confinement loss is obtained. The effect of ellipticity on these characteristics is investigated in detail. It is found that the type of ellipticity of the air holes affects the numerical aperture and hence confinement loss significantly, but it has no crucial effect on either the dispersion or the birefringence for the small and large core PCFs.

The Simulation of the Modes in a Photonic Crystal Bend Waveguide for Two Different Compositions

In this study, we investigated the behavior of the TE mode fields in a photonic crystal bend waveguide, for different lattice constants and radii of dielectric rods in the visible and infrared regions. Results are obtained by using FEMLAB simulation software for two different compositions and discussed.

Schematic representations for teaching the procedure of optical amplification in fiber amplifiers

We present the schematic representations for teaching the procedure of optical amplification in erbium and praseodymium doped fiber amplifiers by using rate equations models. The behaviour of these types of amplifiers is the same as three (for erbium ion) and four (for praseodymium ion) levels atomic systems, respectively. Most of the important characteristics of these amplifiers can be obtained from these simple models and their underlying assumptions. Hence, we can make use of these approaches for teaching the purposes of procedures in fiber amplifiers. For this aim, the gain performances of Er3+ and Pr3+-doped fiber amplifiers are investigated at the educational level, using the temperature-dependent rate equation model.