Erbium-doped optical fibers

Varaksa Y. A., Sinitsyn G. V., and Khodasevich M. A., Transmission capacity of erbium-doped fiber amplifiers as a criterion for quality of erbium-doped optical fibers. Opt Spectrosc. (English translation of Optika i Spektroskopiya) 104,130-134 (2008). 

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... 

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). 

G. R. Walker. N. G. Walker, R. C. Steele, M. J. Creanerand M. C. Brain, Erbium-doped fiber amplifier cascade for mmulti-channel coherent optical transmission, J. Lightwave Tech. 9 (2) 182-193 (1991). 

G. Nykolak, S. A. Kramer, J. R. Simpson, D. J. DiGiovanni, C. R. Giles and H. M. Presby, An erbium-doped multi-mode optical fiber amplifier, IEEE Trans., Photonics Tech. Lett. 3 (12) 1079-1081 (1991). 

SEMICONDUCTOR OPTICAL AMPLIFIERS have received less attention in the literature than amplifiers using optical fibers as the gain medium. Fiber amplifiers, including Erbium-doped fiber amplifiers and Raman amplifiers are currently transforming the world of optical fiber telecommunications as they become incorporated as line amplifiers in high-capacity wavelength-division multiplexed (WDM) transmission systems. However, despite the dominance of fiber amplifiers in the telecommunications marketplace, semiconductor optical amplifiers continue to show potential for application in a range of... 

Thus, for even the very best possible high-gain amplifier with complete inversion (Usp = 1), the noise figure F is never less than 2 (3.01 dB). This is a fundamental result for an IMDD system that can be arrived at more generally using Heisenberg s uncertainty principle as the starting point. While this so-called quantum limit has been approached in other types of optical amplifier (most notably erbium-doped fiber amplifiers), it is never achieved in SOAs because, as Fig. 9 shows, the spontaneous emission factor never reaches the theoretical limit of Usp =. ... 

The transmission distance in optical fiber communications has been greatly increased by the development of erbium-doped fiber amplifiers. Consequently, the main factor limiting the maximum repeater span is now the fiber... 

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. 

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