Performance Analysis on Single- and Double-Pass Ytterbium-Doped Fiber Amplifier in the 1 μm Region

In this work, single- and double-pass configurations of ytterbium-doped optical fiber amplifiers (YDFAs) have been investigated. This low quantum defect rare-earth dopant and their performance near 1 mu m region has been comprehensively investigated on the basis of gain and noise figure in relation with input signal power and input pump power. The obtained results showed that at an input pump power of 100 mW, the gain was proportionally increased with ytterbium-doped fiber (YDF) length for both proposed configurations, but double-pass regime scored higher gain. This is due to the double-propagation of the forwarded and amplified spontaneous emission (ASE) signal into the active medium and hence will maximize the attainable gain near the 1 mu m wavelength region. At YDF length of 5 m, the double-pass technique showed better amplification performance at a lower input signal power of -20 dB compared to the higher input signal power of 0 dB. The maximum gain and optical signal-to-noise ratio (OSNR) attained by double-pass configuration were 24.6 dB and 53.4 dB, respectively. Double-pass amplification at input signal power of -20 dB has increased the gain by 11.2 dB in comparison with the single-pass technique.