An overview on S-band erbium-doped fiber amplifiers

✍ Scribed by S. W. Harun; K. Dimyati; K. K. Jayapalan; H. Ahmad

• Publisher: John Wiley and Sons
• Year: 2007
• Tongue: English
• Weight: 146 KB
• Volume: 4
• Category: Article
• ISSN: 1612-2011
• DOI: 10.1002/lapl.200610064

✦ Synopsis

An erbium-doped fiber amplifier (EDFA) for S-band
signal amplification is designed by using a depressed cladding
erbium-doped fiber (DC-EDF). The fiber's characteristics are
described in terms of the effects of the fiber spooling diameter
on the amplifier's performance. In this experiment, the spooling
diameter required for optimum amplifier gain was around 5–7 cm.
By using a typical two-stage configuration (with a 27 m long
DC-EDF and a 260 mW pump laser power), the maximum small signal
gain obtained was about 32 dB. Yet, by employing a double pass
amplifier configuration with a shorter DC-EDF length and a lower
pump laser power (15 m and 135 mW, respectively), a similar
maximum small signal gain of approximately 30 dB was achieved.
This improvement in gain characteristics however, incurred an
increased noise figure penalty of about 1 dB in comparison to
single-pass amplifier configurations. In order to reduce the
amplifier's noise figure while maintaining its high gain, a
partial double-pass S-band EDFA configuration was introduced. This
configuration provides a high 26.9 dB gain and an improved noise
figure comparable to a single pass configuration. Gain clamping in
S-band EDFAs are also demonstrated by utilizing a fiber Bragg
grating to form an oscillating laser at around 1530 nm. This
technique enables good gain clamping with a gain variation of less
than 1 dB.