H. Rodler

Von GSM zu DECT: Die mobile Sprach- und Datenkommunikation

Dr.-Ing. Hermann Rodler studierte Nachrichtenund Hochfrequenztechnik an der T U München und promovier te 1993 an der Ruhr-Universität Bochum. Seit 1985 ist er bei der Siemens AG tätig, bis 1992 im Bereich Forschung und Entwicklung von optischen Kommunikat ionssys temen. Bis 1996 war er Leiter des Technology Department von Siemens in Japan, danach Projektleiter für die Entwicklung von IP Telefonie und Mobilkommunikat ions-Prototypen. Seit 1997 ist er für die strategische Produktplanung von Sprachund Daten-Kommunikat ionssystemen im Geschäftsbereich Information and Communication Networks verantwortlich.

Impact of the dual-PIN-photodiode series resistance on the noise of tuned optical receivers

Optical front ends are crucial components for both direct detection and heterodyne systems. Serial tuning1 has proved to be suitable for noise suppression without sacrificing a broadband frequency response2-4 A thorough investigation of the noise performance of a serial tuned high impedance design2 shows that, for a sufficiently high transconductance of the preamplifier transistor, three main sources are contributing to the total noise. In Fig. 1 the corresponding equivalent spectral input noise current densities are shown. Trace 1 is the total input noise density, which is in close agreement with measured values,2 trace 2 represents the noise of the diode series resistance of the dual PIN diode.

Comparison of endless polarization control and data- induced polarization switching in an ultrasensitive FSK hetero- dyne system

Endless polarization control1,2 (EPC) and data-induced polarization switching3,4 (DIPS) have been suggested to solve the polarization problem in optical FSK heterodyne receivers. We compare both methods, we believe for the first time, in terms of receiver sensitivity and polarization response speed.

Ultra-High Receiver Sensitivity For Coherent Transmission Systems At 565/140 Mbit/S Using DPSK/FSK Modulation.

It is widely known that heterodyne detection provides an improved receiver sensitivity and selectivity compared to direct detection. Therefore heterodyne systems are very interesting for both long haul transmission and local networks. For long haul transmission the up to 15 dB improvement in receiver sensitivity at high data rates will be the most important issue. This means that the receiver spacing will increase by about 75 km. The most sensitive PSK and DPSK modulation formats are of interest for this application. In LANs and distribution networks it will be very advantageous to transmit a great number of densely spaced channels over one fiber. In the subscriber premises, a heterodyne receiver selects one of them without any switching element. Since the FSK modulation format is very tolerant to laser linewidth and since low cost is an important issue for broadcast systems, FSK systems at moderate data rates with tunable DFB lasers will be used for this application. We demonstrate two transmission experiments with 565 Mbit/s DPSK and 140 Mbit/s FSK modulation, respectively, using different laser types.

Pattern-independent FSK heterodyne transmission with endless polarization control and a 119 photoelectrons/bit receiver sensitivity

Abstract We demonstrate 140-Mbit/s FSK transmission with a -56.7-dBm receiver sensitivity. The system features endless polarization control, Manchester coding to overcome the nonuniform FM response of the DFB laser, and a highly efficient sub-carrier demodulation scheme.