• Schmidt, Markus

Abstract

The globalized world of today is unimaginable without optical lightwave communication technologies. The exchange of information in a fast and flexible way is of substantial importance for the current economy. The first generation of lightwave systems, operating at 0.8 pm, became commercially available in 1980 (San78]. They provided a bit rate of 45 Mb/s and a repeater spacing of about 10 km. During the subsequent two generations, the dispersion minimum of silica single-mode fibers at 1.3 um and InGa AsP-laser sources have been utilized to enhance the performances of optical communication systems by orders of magnitude (Sip95). The fourth generation of systems, which represents the current state of the art technology, operates at 1.55 um, benefiting from a loss minimum of silica fibers in this particular spectral domain (Miy79]. Wavelength-division-multiplexing (WDM), allowing synchronous signal transmission, and Erbium-doped optical amplifiers, providing simultaneous multichannel amplification, gives rise to transoceanic systems, which can transmit information at a total bit rate of more than 1 Tbit/s over a distance of 10000 km [Kah01],[Hei00],[Agr04). Processing of the data streams is ensured by supplying additional components like modulators, photodetectors, WDM-elements and opto-optical switches. For the discussion in the present thesis, optical modulators and filters are of major interest. Such filters are primarily employed in current communication systems to address one particular WDM-channel. Since the characteristic distance between two adjacent channels is about 0.8 nm (Q 1550 um), high spectral selectivities have to be …

Topics

• impedance spectroscopy
• dispersion
• Erbium