R.J.W. Jonker

Interferometric crosstalk reduction by phase scrambling

Interferometric crosstalk, arising from the detection of undesired signals at the same nominal wavelength, may introduce large power penalties and bit-error rate (BER) floor significantly restricting the scalability of optical networks. In this paper, interferometric crosstalk reduction in optical wavelength-division multiplexing (WDM) networks by phase scrambling is theoretically and experimentally investigated. Enhancement of 7- and 5-dB tolerance toward crosstalk is measured in a 2.5-Gb/s transmission link of 100 km and 200 km of SSMF, respectively. This result proves the feasibility of optical networking in the local area network/metropolitan area network (LAN/MAN) domain while tolerating the relatively high crosstalk levels of present integrated optical switching and cross-connect technology. Experiment is in good agreement with theory. Recommendations on the use of phase scrambling to reduce crosstalk in WDM systems are given.

Cost-effective up to 40 Gb/s transmission performance of 1310 nm directly Modulated lasers for short- to medium-range distances

This paper presents successful 20 and 40 Gb/s potentially low-cost transmission experiments using 1310 nm directly modulated distributed feedback lasers (DMLs) in the very-short- to medium-range distances. This paper will recommend operating conditions for error-free transmission at these bit rates and distances. Pattern dependencies are identified. General characteristics of direct laser modulation are confirmed by dedicated simulation software and experiments. Unknown laser parameters needed to solve the rate equations are estimated by a given method based on measured and calculated small- and large-signal DML responses.

Experimental evaluation of optical crosstalk mitigation using phase scrambling

We report an experimental study of mitigation of optical homodyne crosstalk by phase scrambling. This is obtained by frequency shifting the signal-crosstalk heating noise power out of the receiver bandwidth. An increased tolerance to crosstalk of 7 and 5 dB is measured in a 2.5-Gb/s link of result indicates the feasibility of optical networking in the LAN/MAN domain by tolerating the relatively high crosstalk levels of present optical switching technology. Our experiment is in good agreement with theoretical results.

Experimental assessment of 1.3 μm telecommunication systems incorporating a praseodymium doped fiber amplifier (PDFA)

We have investigated the system performance of an experimental Praseodymium Doped Fibre Amplifier (PDFA) in an optical transmission system operating at 1.3μm. Experimental evaluation of the PDFA, based on Bit Error Rate (BER) measurements, is presented for the PDFA in copropagating and bidirectional configurations as a function of both wavelength and optical input power. The performance is analysed for both NRZ and RZ modulation format at a bitrate of 10 Gbit/s. The polarisation dependency of the PDFA is less than 0.2 dB. The results of an experimental analysis of the PDFA in an optical recirculating loop are shown for a NRZ modulated pseudo random data stream at 622 Mbit/s. A total span of approximately 2000 km is covered. Furthermore, the results of transmission experiments using the optical circulating loop at 10 Gbit/s are presented.