The main aim of this paper is to analyze the influence of the modulation techniques; on the performance of coded orthogonal frequency-division multiplexing (COFDM) based Radio over Fiber (RoF) system. The modelling of the COFDM scheme for RoF system has been completely done by using software Optisystem. Both analysis and simulation results are presented for 16-QAM and 16-QPSK modulation techniq...

We have measured the refractive index change (RIC) induced in a fiber Bragg grating (FBG) written in a Yb-doped fiber amplifier (YB-FBG) because of the amplifier pumping. The measurement was performed by exploiting the high sensitivity of the YD-FBG transmission to the RIC. We have separated between electronic and thermal contributions to the RIC based on the difference between the time-scales ...

We propose and demonstrate a novel sensor by using a single-fiber Bragg grating that can simultaneously measure strain and temperature with the aid of an erbium-doped fiber amplifier. By using a linear variation in the amplified spontaneous emission power of the erbium-doped fiber amplifier with temperature, we determine the temperature. By subtracting the temperature effect from the fiber Brag...

An all-fiber amplifier for a single-frequency blue laser was demonstrated for the first time, to the best of our knowledge. Over 150 mW continuous-wave single-transverse-mode blue laser output was obtained with a 10 m 1000 ppm thulium-doped fluoride fiber pumped by a 1125 nm fiber laser at a power of 2 W. The output power was limited due to the onset of the competitive lasing at 783 nm. Photoda...

Thermal effects, which limit the average power, can be minimized by using low-doped, longer gain fibers, whereas the presence of nonlinear effects requires use of high-doped, shorter fibers to maximize the peak power. We propose the use of varying doping levels along the gain fiber to circumvent these opposing requirements. By analogy to dispersion management and nonlinearity management, we ref...

We investigate high brightness pumping of a multi-kW Yb fiber amplifier in a bi-directional pumping configuration. Each pump outputs 2 kW in a 200 μm, 0.2 NA multi-mode fiber. Gold-coated specialty gain fibers, with 17 m MFD and 5-dB/meter pump absorption, have been developed. The maximum fiber amplifier output power is 3.1 kW, limited by multi-mode instability, with 90% O-O efficiency 12 GHz ...

In this chapter, we propose several schemes for fiber amplifiers which are all using fiber Bragg gratings (FBGs) as the key elements for their advantages of better uniformity, higher contrast ratio and lower cost. Several applications using FBG-based fiber amplifiers are also introduced. Therefore, this chapter initiates the overview of FBGs characteristics in Sec. 1, then addresses the FBGs pl...

We demonstrate a single-frequency gain-switched Ho-doped fiber laser based on heavily doped silicate glass fiber fabricated in-house. A Q-switched Tm-doped fiber laser at 1.95 μm was used to gain-switch the Ho-doped fiber laser via in-band pumping. Output power of the single-frequency gain-switched pulses has been amplified in a cladding-pumped Tm-Ho-codoped fiber amplifier with 1.2 m active fi...

This work describes the comparison of the amplification characteristics (gain) and the Noise figure (NF) of the Thulium and Erbium in three different host materials which the Yttria Alumina-Silica glass, Fluoride and Tellurite fiber glass. The gain using these host materials covers the range 1.45-1.65 μm. Thulium doped fiber amplifier (TDFAs) operated in the region of wavelength (1480-1510 nm) ...