Catálogo de publicaciones - libros

We experimentally show that a strongly asymmetric nonlinear optical loop mirror (NOLM) based 2-R regenerator does not degrade the pulse quality in a fiber optic transmission line. The signal at the NOLM output port shows only negligible chirp if a fundamental soliton propagates in the strong arm of the NOLM. This behavior is measured for splitting ratios of 91:09 and 85:15. The NOLM does not insert penalties regarding the pulse shape and is therefore suitable for inline regeneration of optical transmission lines.

Switching of an optical signal comprising individual OTDM channels of unequal amplitudes in a nonlinear optical loop mirror is investigated. The propagation dynamics of unequal-channel data streams in a switch-guided, dispersion-managed link are also studied

All-Optical Re-amplification and Re-shaping (2R) exploiting spectral shift induced by Self-Phase-Modulation (SPM) in a Semiconductor Optical Amplifier (SOA) is presented. Theoretical model taking into account Carrier Density (CD), Carrier Heating (CH) and Spectral Hole Burning (SHB) is experimentally validated using 3 ps optical pulses.

Necessity to exploit new bandwidth has moved research interest towards new amplification solution, which support the exploitation of the fiber bandwidth and of short optical pulses. 2P-OPA seems quite promising as they offer high project flexibility, high gain uniformity and low accumulated dispersion. We present and discuss a 2P-OPA realization and its behavior with CW and picosecond pulses.

Free Space Optics (FSO) is an excellent supplement to conventional radio links and fibre optics. It is a broadband wireless solution for the “Last Mile” connectivity gap throughout metropolitan networks.

At the Department of Communications and Wave Propagation several FSO-systems have been developed within the past 5 years. Thereby the main effort was laid on using LEDs instead of laser diodes. One system is based on a modular concept using available standard components, used for distances of about 300 m at a specific power margin of 25 dB/km.

Additionally the research group “OptiKom” investigates the reliability and availability for different network-architectures (ring, mesh and star).

In an non-conventionally biased m3m centrosymmetric photorefractive crystal, the combination of the internal photorefractive field with the external static electric field can introduce a conversion between the transverse vector components of the read-out beam at infrared wavelengths.

We demonstrate that a free ASE light re-circulation in EDFA based WDM ring networks provides an effective gain clamping technique. Proper network and amplifier design ensure signal power overshoots lower than 2.5 dB under 23/24 WDM channels add-drop operations.

A novel scheme for direct detection of DPSK signals using FBGs is proposed. It alleviates the stability requirements of conventional one-bit-delay demodulators and it is suitable for very high data-rates.