Erbium fiber doping

In optical fibers, erbium is doped at regular intervals in order to amplify signals. This works as follows erbium converts other wavelengths that are sent through the fiber to the wavelength of the signal that carries the information (Emsley 2001). 

Transmission properties. The recent interest in erbium- (Er +-)doped fiber amplifiers (EDFA) originates from the recognized fact that the optical fiber transmission windows for silica or fluoride glasses (fig. 34) are in tune with the wavelengths of the two Er + transitions I13/2 I15/2 at 1.5 pm, and Ii 1/2 I13/2 at 2.7 pm. 

Fig. 15. Erbium-doped fiber amplifier where x represents spHces and WDM is a wavelength division multiplexer combining the signal and pump...

A great future is predicted for glass-fiber technology. Equally essential will be light amplifiers in which the glass fibers are doped with erbium. 

Various types of optical fibers are used for specific applications. For example, multimode fibers are used primarily in enterprise systems buildings, offices, campuses. Special single-mode transmission fibers exist for submarine applications, and for metropolitan and long-haul terrestrial applications. And in addition to these transmission fibers, there are various specialty fibers for performing dispersion compensation (dispersion compensating fiber), optical amplification (erbium-doped fiber), and other special functions. 

Rg. 12. Erbium-doped light amplifier. Light from a diode laser pump excites erbium ioas in segment of an optical fiber. These ions then emit light and thus boost a passing optical signal. (After AT T Bell Laboratories)... 

Nielsen, T.N., et al. 3 28 Tb/s 82 x 40 Gh/s) Transmission Over 3 < 300 km of Nonzero-dispersion Fiber Using Dual C- and L-band Hybrid Raman/Erbium-doped Inline Amplifiers, Optical Fiber Communication Conference, post-deadline paper 29, March 2000. 

For the continuous-wave semiconductor (AlGaAs) distributed feed back lasers (DFB) used in telecommunication technology today a nonlinear refractive index n2=S cm2/GW would be necessary for all-optical switching, which is presumably impossible to reach. Including an Erbium doped fiber amplifier (EDFA) the needed nonlinearity drops only by a factor of ten. 

Interest in the development of metal-organic precursors for the lanthanide elements is due to the many important apphcations of lanthanide-containing materials. These include erbium-doped semiconductors for use as optical fiber communications, lanthanide-doped GaN for fiiU color displays, high-temperature superconductors, and lanthanide-doped ferroelectric see Ferroelectricity) phases. Despite the importance of these materials, lanthanide film growth precursors... 

CW 1617 nm emission with a slope eflflciency of 51.7 % has been observed in a 0.5 at.% Er YAG ceramic laser [184]. Eflflcient operation of the high-power erbium-doped polycrystalline Er YAG ceramic laser was resonantly pumped by using a high-power 1532-nm Er,Yb fiber laser. Lasing characteristics of Er YAG ceramics with different Er " concentrations were evaluated and compared. With an OC of 15 % transmission, the 0.5 at.% Er -doped YAG ceramic laser generated 14 W of output power at 1617 nm for 28.8 W of incident pump power at 1532 nm. 

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