Design and Implementation of Efficient Broadband Bismuth/Erbium Co-Doped Fibre Amplifier

Optical fibers are a proper medium for transmitting and receiving data among short and long distances. Signal transmitted through fibers is attenuated. Therefore, fiber amplifiers play an important role in telecommunication system to recover the attenuated signal. Erbium doped fiber amplifiers are the most common used amplifiers in transmission systems which only use a narrow bandwidth of telecommunication window between 1500nm to 1620nm. Research has been done on increasing the bandwidth of optical fiber amplifiers to use other wavelengths of telecommunication window. Bismuth doped fiber amplifiers are novel amplifiers which operates within a wide range of wavelengths between 1100nm to 1700nm region. In this research a Bismuth/Erbium co-doped fiber amplifier is studied and designed which covers a wide region of telecommunication window. Amplifier performance is investigated using both theoretical and experimental analysis. An optimized amplifier is implemented, and gain-bandwidth of the amplifier is calculated using experimental and theoretical results. First, an EDFA is modelled theoretically using three level energy system. Gain and gain-bandwidth of the amplifier are calculated using simulation results. In this model it is shown that EDFA only use a very narrow bandwidth between 1500nm to 1560nm. Second, some experiments are done on BEDF to investigate its properties and performance. Absorption, emission, up-conversion emission, On/Off gain (ESA), lifetime, net gain and diameter measurement are experiments that are done to evaluate the BEDF. Experimental results help us extract some principal parameters of simulation and energy levels of BEDFA. In the last step, a BEDFA is modelled theoretically using three level energy system. Different cases are studied for this purpose: 1- model without considering gain affecting factors including Excited State Absorption (ESA), cooperative up-conversion (CUP) and pair induced quenching (PIQ), 2- model with ESA 3- model with CUP and 4- model with PIQ. In case 1 an optimized BEDFA is presented for best design of higher gain and shorter length. Gain-bandwidth of the amplifier is calculated which is between 1300nm to 1550nm. For cases 2,3 and 4 it is shown that gain of the amplifier decreases significantly due to ESA, CUP and PIQ effect