H. Haldun Goktas

Gain Flattening Configurations at the L Band Erbium Doped Fiber Amplifiers

Many configurations are used to flatten the Erbium doped fiber amplifiers (EDFA) gain. In this study, output signal gain and noise figure of one-stage, two-stage, two-stage with gain flattening filter, and double-pass L band EDFA configurations are analyzed. -20 dB power and between of 1565-1610 nm L band signals are applied to this four configurations and reached to highest gain in double-pass configuration, lowest noise figure in two-stage amplifier and two-stage with gain flattening filter configurations, and lowest gain ripple in two-stages gain flattening filter configuration.

Design of a Fiber Bragg Grating based temperature sensor

In this study, a Fiber Bragg Grating (FBG) based temperature sensor is designed. Simulation is conducted to observe FBGs response to the temperature change. The temperature incident on the FBG is gradually changed from 0°C to 60°C in 10°C steps and the frequency shifts in both RF and optical spectrum are observed.

The fiber optical sensing based on Brillouin scattering

Fiber optic sensor technology based on Brillouin scattering is rapidly spreading due to quantities is great precision measured such as temperature, strain and vibration in the long haul distributed sensing. In this study Brillouin scattering has been analyzed in the single mode fiber. An experimental setup has been done using OptiSystem 12.0, and Brillouin scattering monitored graphically in the 50 km optical fiber cable.

Optimization of the three stages L band EDFA

In this study, fiber lengths of each stage of the three stages L band erbium doped fiber amplifier (L-EDFA) and the pump laser power are optimized to achieve the maximum gain, the minimum noise figure and the minimum gain ripple. It is obtained on an average 34.7-37.1 dB gain, 6.28-6.0 dB noise figure, and 2.13-2.28 dB gain ripple along all L band for the 980-1480nm pump wavelengths, respectively.

C band erbium doped fiber amplifier as a flat gain optical amplifier

The most prevalent optical amplifier is erbium doped fiber amplifiers (EDFA) that has a wavelength dependent non-flat gain spectrum. Many configurations are used to flatten the EDFA gain. In this study, the fluctuant at the output signal gain depending on the input signal power was examined and it is shown that a C band EDFA can be used as a flat gain amplifier without a gain flattening tool.

Auto City: A System for Generating 3D Virtual Cities for Simulation Systems on GIS Maps

Abstract 3D Virtual Reality (VR) platforms developed on computers can prevent users from possible risks of real physical environrnents. We aze developing hazdware and software based training system, in which training of driver candidates is possible. As a pazt of the system, virtual city generation is essential. We devised an algorithmic system which automatically generates virtual cities supporting several different map formats (i.e. DTED, HTF, SRTM, and DEM). Depending on the conditions submitted, the system generates different layouts for the cities even on the same geographical site. The current mechanism is based on Height Tile File (HTF) maps and initially The New York city model has been successfully implemented and real time 3D navigation in the city using a standard Intel P4 based PC is possible.

Using single-mode fiber as temperature sensor

Fiber optic cables are widely used in sensor applications of temperature, strain and pressure. The long sensing range, minimal power consumption and other advantages of classic fiber cables make these sensor systems very appealing. In this paper, the application of single mode fiber as temperature sensor and its effect are studied.

The analyzes of the Brillouin scattering for the different fiber types

In this study, Brillouin scattering is experimentally analyzed in the single mode fiber and dispersion shifted fiber optic cable. For this reason, wavelength of the 1550 nm laser is varied between 1526 nm and 1570 nm, and Brillouin shift is measured for both fiber types. Consequently, Brillouin scattering is higher in the single mode fiber.

Gain and noise figure enhancements of both C and L bands double pass Erbium Doped Fiber Amplifier

In this study, designed and optimized C and L band Erbium Doped Fiber Amplifiers (EDFA) around 70 nm bandwidth, 36.53 dB average gain with an average noise figure of 5.8 dB properties are used. For this purpose, 16 channels Wavelength Division Multiplexed (WDM) system with channel spacing of 5.3 nm is taken into account. -30 dBm powers at the input signals (1530 nm-1610 nm) are applied to three port filter and then input signals are separated into C and L bands. Each band signals are separately amplified in double pass configuration. Finally, all signals are combined into a coupler and the overall configuration has wide bandwidth, high gain and low noise.

Prediction of the brain temperature from other body temperatures in hypothermia induced rats by using artificial neural networks

In this study, a microcontroller based temperature controlled hypothermia induction system is realized. The novelty of the experimental system is in using a thermoelectric Peltier cooler to bring the body temperature to hypothermic levels. The right and left ear, rectum, and brain temperatures of a rat are measured with this system. Then, an artificial neural network (ANN) is trained using temperature data to predict brain temperature from other body temperatures. It is shown that the system has the capability to predict the brain temperature with low error from rectum temperature measurements. The results from this empirical prototype also show that it is possible to use the system on humans to induce local hypothermia safely, where an interior temperature probe in the scalp is eliminated.