Investigation on Double Pass Amplification by employing Zr-EDF as a gain medium with different types of reflectors

Abstract

In this paper, the amplification for double-pass operation is demonstrated by using a newly doped fiber namely as Zirconia based erbium doped fiber (Zr-EDF) with a different type of reflectors which are optical circulator and a broadband fiber mirror (BFM). The concept of double pass amplification is based on the forwarded and amplified spontaneous emission (ASE) signal that will propagate twice into the gain medium and thus will increase the gain performance in the C- and L- band region. Optical circulator and BFM are placed at the end of the cavity and used as the signal reflector to ensure that the signal will be reflected back into the gain medium, Zr-EDF. The amplification performance of single and double pass Zr-EDFA by utilizing optical circulator and BFM as signal reflectors are investigated at high and low input signal powers, -10 and -30 dBm, respectively. The double pass approach shows a better amplification performance at low input signal power of -30 dBm, compared to the high input signal power of -10 dBm. At low input signal power of -30 dBm, the maximum gain of 40.3 dB is achieved for double pass amplification at a wavelength of 1560 nm. The gain enhancement of 12.30 dB is observed between the single and double pass amplification with BFM as the reflector with the low input signal power. Instead of that, the performance analysis of double pass amplification by utilizing the optical circulator for varying the length of gain medium from 0.5 m to 2 m and pump power from 67 mW to 130 mW is further investigated. From the results, it shows that with the length of 1m Zr-EDF and 130 mW of pump power shows the optimum length and pump power due to the highest gain with lowest noise figure performance.