Abstract:We propose a new pumping method for optical fiber amplifiers at 1480 nm and 980 nm that is able to provide high gain and low noise-figure. The gain and noise figure obtained were 38.3 dB and 5.5 dB with an improvement of 3.8 dB and 1.4 dB, respectively, at 1550 nm, for −30 dBm input power when compared to its counterpumped design. This design also delivers higher gain and lower noise figure when compared to the common bi-directional dual-pumped designs. A power conversion efficiency of 44.5% was achieved in this design. Keywords: Optical amplifiers, pumping methods, erbium-doped Classification: Photonics devices, circuits, and systems References

The effects of the length t of elements 1 and 5 are also analyzed, and the results are shown in Figure 7. It is observed that when the length t decreases, the resonant frequency of the antenna is shifted to high frequencies and the impedance matching is also degraded. On the other hand, when the length t increases, the resonant frequency of the antenna decreases and the impedance matching is also degraded. The antenna directivity and gain are also computed and listed in Table 1 for comparison. The results indicate that there exists an optimal length t for achieving a maximum antenna gain. This is largely because, with an optimal length t chosen, the null excited currents will occur near points C, D, E, and F (see Fig. 4), as desired. In this case all portions in elements 1, 3, and 5 are of the same phase, thus optimal constructive radiation for the proposed antenna can be expected. Also note that the optimal length t (56 mm) for achieving a maximum antenna gain (see Table 1) is the same as that for achieving a maximum impedance bandwidth (see Fig. 7). Figure 8 plots the measured radiation patterns at 2442 MHz for the constructed prototype. Good omnidirectional radiation pattern in the azimuthal plane ( x-y plane) is seen. In the elevation plane ( x-z and y-z planes), small or negligible side lobes are also seen. The measured results in general also agree with the simulated radiation patterns shown in Figure 9. Figure 10 presents the measured and simulated antenna gain against frequency for the constructed prototype. Good agreement between the measured and simulated results is observed. A high antenna gain of about 6.6 -6.8 dBi for frequencies across the 2.4-GHz band is obtained, which is much higher than that of a conventional half-wavelength dipole antenna. CONCLUSIONA high-gain printed dipole antenna has been proposed, constructed, and tested. The proposed antenna has a simple configuration and is easy to implement with a low cost. A constructed prototype suitable for application in the 2.4-GHz band for WLAN operation has been studied. The prototype has a narrow width of 10 mm and a total length of 202 mm only (1.64 wavelengths at 2442 MHz) and performs as a good collinear array antenna with three in-phase half-wavelength resonant elements. A high antenna gain level of about 6.6 -6.8 dBi for frequencies across the 2.4-GHz band has been obtained. This antenna gain level is much larger than that of a conventional half-wavelength dipole antenna. 1559.4 and 1563.4 nm, respectively. A bandwidth of 85.6 nm (1515.4 -1601.0 nm) and 67.3 nm (1545.2-1612.5 nm) was obtained for the feedback and nonfeedback systems, respectively, at a power density of Ϫ30 dBm/nm.1. B. Drozd and W.T. Joines, Comparison of coaxial dipole antennas for applications in the near-field and far-field regions, Microwave J 47 (2004), 160

No abstract

No abstract