The noise figure and gain improvement of double‐pass C‐band EDFA

Abstract

In this study, the noise figure (NF) improvement is demonstrated in double-pass C-band erbium-doped fiber amplifier. It is used the short length of unpumped erbium doped fiber (EDF) within a circulator-based loop mirror which is reduced amplified spontaneous emission (ASE). The unpumped EDF attenuates part of the ASE that is then reflected back for a double pass configuration which in turn, helps to improve the gain and NF. The proposed configuration has lower NF and higher gain than conventional double pass scheme. Thus, it can be easily applied for practical application.ABSTRACT: This article presents a new quadrature voltage-controlled oscillator (QVCO). The LC-tank QVCO consists of two first-harmonic injection-locked oscillators (ILOs). The outputs of one ILO are injected to the common nodes of capacitors on the other ILO and vice versa so as to force the two ILOs operate in quadrature. At the supply voltage of 1.1 V, the total power consumption is 5.94 mW. The free-running frequency tuning range is 11.5%, tunable from 6.56 to 7.36 GHz as the tuning voltage is varied from 0.0 to 2 V. The QVCO has been implemented with the TSMC 0.18-lm CMOS technology and the die area is 0.504 3 0.803 mm 2 . The measured phase noise at 1-MHz offset is 2123.01 dBc/Hz at the oscillation frequency of 7.34 GHz and the figure of merit of the proposed QVCO is about 2192.5 dBc/Hz.

An L‐band‐cascaded erbium‐doped fiber amplifier for uniform gain without gain equalizing filter

“…The noise figure of an EDFA is given by: where, G is the gain associated with the fiber, P ASE is the ASE power, which consists of both forward and backward ASE, h is the Planck constant, ν is the frequency of the signal and Δ ν is the signal bandwidth. The gain for three stage EDFA was adopted from the reported two stage configuration and is given by, where, P s and P p is the signal and pump power in the forward direction. α s is the absorption of the signal, L n are the lengths of the respective fibers.…”

A novel Michelson interferometer of high interference degree with the application of bi‐direction erbium‐doped fiber amplifier

“…Calculating the noise power of ASE, the gain (G) of the EDFA under disparate power of amplification could be obtained. The calculation formula of G is shown in . …”

“…Once the gain of the amplifier and the noise power of ASE are obtained, the noise figure (NF) can be calculated of the re‐amplifier after twice amplification. The calculation formula of NF is shown in .…”

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

“…Thus, it is useful to achieve a low noise figure in proposed configuration as well as high gain. The noise figure is calculated by the below formula [54]; (2) In the proposed system, depending upon the lengths of the fibers obtained from the first pass of the signal, the gain of the amplifier is [43,54,[61][62][63][64]:…”