[Show abstract][Hide abstract] ABSTRACT: This paper reviews ultrahigh-speed data transmission in optical fibers based on optical time division multiplexing (OTDM) transmission technology. Optical signal processing in the transmitter and receiver as well as the requirements on ultrahigh-speed data transmission over a fiber link are discussed. Finally, results of several OTDM-transmission experiments, including 160-Gb/s transmission over 4320 km, 1.28-Tb/s transmission over 240 km, and 2.56-Tb/s transmission over 160-km fiber link, are described
Preview · Article · Jan 2007 · Journal of Lightwave Technology
[Show abstract][Hide abstract] ABSTRACT: A transmitter capable of producing 400 fs phase coherent pulses is reported. The feasibility is shown in an OTDM transmission experiment of a single-polarization 640 Gbit/s DPSK signal over 2×80 km in a single wavelength channel.
[Show abstract][Hide abstract] ABSTRACT: We experimentally investigate the switching performance of interferometric gates based on highly nonlinear fiber (HNLF), a Kerr-gate and a Nonlinear Optical Loop Mirror. Switching windows are measured and compared for different operation conditions and HNLFs.
[Show abstract][Hide abstract] ABSTRACT: By combining the techniques of optical TDM with polarisation multiplexing and DQPSK modulation format, 240 km transmission of 1.28 Tbit/s and 160 km transmission of 2.56 Tbit/s has been performed in a single wavelength channel.
No preview · Article · Mar 2006 · Electronics Letters
[Show abstract][Hide abstract] ABSTRACT: The performance of a NOLM gate as an OTDM demultiplexer for 640 Gbit/s to 40 Gbit/s was investigated considering the characterization of the switching windows through the integrated contrast ratio. The results show that short loop lengths should be preferred.
[Show abstract][Hide abstract] ABSTRACT: We propose a simple filter scheme to reduce pattern effects in an SOA. This filter was applied to an SOA-based wavelength converter at 40Gb/s, resulting in a significant improvement of the wavelength converted data signal.
[Show abstract][Hide abstract] ABSTRACT: We report on components and techniques for transmission beyond 100 Gbit/s. In particular the impact of phase-modulation, optical signal processing techniques, Raman amplification and fiber properties on the transmission performance are discussed.
[Show abstract][Hide abstract] ABSTRACT: We describe a transmission system having a data rate of 160Gbit/s based on the RZ-DPSK modulation format. The 160Gbit/s single-polarization signal is generated by optical time division multiplexing technology using the base rate of 40 Gbit/s. The setup is explained and results are given with a special focus on the stability issue of the transmission system. The pulse source, the optical gate for demultiplexing, the clock recovery and the balanced photo-detector are based on semiconductor components. We present long-term bit error measurements (10 hours) over two different long-haul fiber links. The first link comprises 3 x 106 km standard single mode fiber and uses a PMD mitigation scheme. The other link consists of 4 dispersion managed 80 km fiber spans without the need for an additional PMD compensation. Using EDFA amplification solely and also no FEC, error-free operation was achieved over several hours, only limited by slow drift effects in the laboratory system.
No preview · Article · May 2005 · IEICE Transactions on Communications
[Show abstract][Hide abstract] ABSTRACT: A 40 GHz clock signal is recovered from a single-polarisation 320 Gbit/s data signal using a bidirectionally operated electroabsorption modulator (EAM) as phase comparator. The clock recovery was operated in a single-polarisation 320 Gbit/s, 160 km transmission experiment.
[Show abstract][Hide abstract] ABSTRACT: Measurements of eye diagrams of 320 Gbit/s DPSK signals after 160 km transmission are reported using an optical sampling system with clock recovery and 1.0 ps resolution, which accepts amplitude or phase modulated data signals and allows measurements with large persistence time.
[Show abstract][Hide abstract] ABSTRACT: We report an all-optical add-drop multiplexer based on a Kerr-gate comprising highly nonlinear fiber. Error-free operation is obtained for all channels at 160 Gbit/s. The device can operate up to 320 Gbit/s, which is demonstrated by eye diagram measurements.
[Show abstract][Hide abstract] ABSTRACT: Long-term BER measurements (10 h) of a single-channel 160 Gbit/s transmission over 4×80 km high-dispersion fibre are reported, using a single polarisation signal, RZ-DPSK coding and EDFA amplification solely. Pulse source, demultiplexing optical gate, clock recovery and the balanced detector are based on semiconductor components. Completely error-free transmission was observed for more than 5 h without using FEC.
No preview · Article · Mar 2005 · Electronics Letters
[Show abstract][Hide abstract] ABSTRACT: We investigated the cross-phase modulation (XPM) induced phase shift in a highly nonlinear fiber using a Kerr-switch configuration. The switch was tested as demultiplexer of RZ-DPSK data signals up to 320 Gbit/s.
[Show abstract][Hide abstract] ABSTRACT: A novel scheme for all-optical exclusive-OR (XOR) operating at 160 Gb/s is proposed and analyzed by means of numerical simulations. It consists of a Mach-Zehnder interferometer (MZI) where a semiconductor optical amplifier (SOA) is placed in each of its arms. This SOA-MZI setup is coupled to a delay interferometer, which acts as a signal regenerator. It is shown that error-free operation can be achieved at a data rate of 160 Gb/s, indicating that the proposed scheme is not limited by the SOA recovery time.
No preview · Article · Jan 2005 · Journal of Lightwave Technology
[Show abstract][Hide abstract] ABSTRACT: We report 7 GHz cut-off frequency, 2.5 and 5 Gb s−1 eye pattern measurements upon direct modulation of 1.3 μm quantum dot lasers grown without incorporating phosphorus in the layers. Passive mode-locking is achieved from very low frequencies up to 50 GHz and hybrid mode-locking is achieved up to 20 GHz. The minimum pulse width of the Fourier-limited pulses at 50 GHz is 3 ps, with an uncorrelated timing jitter below 1 ps. The lasers are optimized for high frequency operation by a ridge waveguide design that includes etching through the active layer and ridge widths down to 1 μm. The far-field shape for 1 μm is close to circular with a remaining asymmetry of 1.2.
Full-text · Article · Nov 2004 · New Journal of Physics
[Show abstract][Hide abstract] ABSTRACT: The paper reports on optical signal processing for data transmission at 160 Gbit/s per wavelength channel using the DPSK-modulation format in connection with optical time division multiplexing (OTDM) technology.
[Show abstract][Hide abstract] ABSTRACT: Today, commercial fiber optical transmission systems are operated at a data rate of 10 or 40 Gbit/s per wavelength channel. The optical time division multiplexing (OTDM) technique allows for the investigation of the next generation TDM data rate of 160 Gbit/s while electrical signal processing at 160 Gbit/s is not yet available. In an OTDM transmission system, the key functions of the transmission system are realized using ultrafast all-optical or electro-optical network elements. In this paper, the recent progress in ultrafast technologies for 160 Gbit/s OTDM transmission systems is reviewed. The focus will be on techniques to realize optical pulse sources and ultrafast optical gates which operate on a time scale of a few picoseconds to a few hundred femtoseconds. They are the key elements of a 160 Gbit/s OTDM transmission system and are applied for various functions in the system. The paper focuses in particular on the application of ultrafast optical technologies for measurement purposes. In an optical communication system the quality of the data signal can be inferred from the optical eye diagram of the data signal. Presently, the measurement of optical eye diagrams at a data rate of 160 Gbit/s is inhibited by the limited bandwidth of photodetectors and electrical sampling oscilloscopes. By realizing an all-optical sampling system using the ultrafast technologies discussed before, the bandwidth of such an optical sampling system exceeds 400 GHz and allows for eye diagram measurements up to 320 Gbit/s.
No preview · Article · Jan 2004 · Proceedings of SPIE - The International Society for Optical Engineering
[Show abstract][Hide abstract] ABSTRACT: Clock recovery from a 160 Gbit/s data signal is demonstrated using a bidirectionally operated electroabsorption modulator (EAM) as phase comparator. Employing a differential detection scheme, excellent locking stability is achieved. The recovered clock signal allows error-free 160 Gbit/s transmission.
No preview · Article · Aug 2003 · Electronics Letters
[Show abstract][Hide abstract] ABSTRACT: The self cascading of an electroabsorption modulator (EAM) with commercially available components improves the switching performance of a single electroabsorption modulator. The improved performance is demonstrated in 160 to 40 Gbit/s demultiplexing experiments and 40 GHz pulse generation.