Experimental investigation of the gain flatness characteristics for 1.55 /spl mu/m erbium-doped fluoride fiber amplifiers

Two crystallographic sites in erbium-doped fluoride glass by frequency-resolved and site-selective spectroscopies

“…Erbium ions in this site have 4 I 13=2 lifetime of around 11 Table 2 Positions of the Stark levels (cm À1 ) of the 4 ms and a Stark splitting of the 4 I 15=2 manifold extending up to 333 cm À1 . In site B (minority site), the site distribution is peaked at high energy (around 6575 cm À1 ) and 4 I 13=2 lifetime is shorter than in site A (around 5 ms) with a Stark splitting extending up to 302 cm À1 .…”

“…Thus, Pr 3þ and Tm 3þ -doped fluoride glasses have shown good capabilities for amplification around 1.3 lm [2] and 1.47 lm [3] in telecommunications systems. Erbium-doped fluoride fiber amplifiers (EDFFA) have been demonstrated and have been used for their flat gain bandwidth around 1.55 lm [4]. It is known that the spectroscopic properties of these different rare-earth ions, related to the environment of the ions, are strongly dependent on the nature of the glass.…”

An efficient gain-flattened C-band Erbium-doped fiber amplifier

“…Several approaches have been proposed for achieving a flat gain with a wide amplification bandwidth such as changing new fiber materials [1,2] and inserting gain equalizers [3,4]. A long period grating and a Mach-Zhender filter have been used to flatten the gain spectrum of an EDFA, but these components are expensive and sensitive to temperature and strain [5].…”

Comparison of the Performances of NRZ and RZ WDM Systems with Long Amplifier Spacing and Dispersion Compensation

“…Since the channels are located far away from the dispersion-zero point, we ignore the FWM effects on the system. The nonuniform EDFA gain is a problem in WDM system, some methods are introduced to decrease the gain difference of different channels [8][9][10]. As to the chromatic dispersion, the use of dispersion compensation fiber (DCF) has been emerging as the most practical technique because of its manufacturability, stability over temperature and wideband dispersion compensating characteristics [11][12][13][14][15].…”