Juraj Slovak

Cascadability and Regenerative Properties of SOA All-Optical DPSK Wavelength Converters

A novel all-optical differential phase-shift keying wavelength converter based on semiconductor optical amplifier nonlinearities is demonstrated in the 25- to 40-Gb/s range with pseudorandom binary sequence of 27-1, and its regenerative properties as well as the cascadability are discussed

All-optical DPSK wavelength converter based on MZI with integrated SOAs and phase shifters

An integrated MZI-SOA device is developed for all-optical wavelength conversion of DPSK signals. The functionality is investigated close to 40 Gb/s and error free operation with less then 1 dB penalty is demonstrated.

Jitter analysis of all-optical clock recovery at 40 GHz

The jitter of optical clock recovery based on self-pulsating PhaseCOMB-lasers is analyzed using a new generation sampling scope. An excellent restoration function of the clock is demonstrated at 40 GHz even for strongly degraded signals.

60 GHz millimeter-wave broadband wireless access demonstrator for the next-generation mobile internet

A novel demonstrator of broadband wireless access for future mobile internet was investigated using steered antennas and optical 60 GHz millimeter-wave sources without rf-electronics in the control station. Key device was a self-pulsating laser designed for 60 GHz operation and a remote stabilization by a sub-harmonic pulse source in a central master control station. Error free operation of HFR system at 155 Mb/s (BER less than 10/sup -10/) was demonstrated, without penalty neither for fiber distribution of the optical microwave signal nor for the remote stabilization of the SPL via fiber. Future broadband wireless connections can be done in a cost effective way by the proposed system based on the SPL as optical millimeter-wave source applying optical beam forming.

Record field demonstration of C-band multi-terabit 16QAM, 32QAM and 64QAM over 762km of SSMF

We demonstrate a record 38.4Tb/s 64QAM C-band transmission over 762km of field deployed SSMF fiber, connecting Lyon and Marseille, France, employing hybrid EDFA-Raman amplification and achieve a spectral efficiency of 8b/s/Hz. Furthermore, we demonstrate, for the first time to our knowledge, flexi-rate transmission over the same commercial link, using quad-carrier 1Tb/s 16QAM (24.0 Tb/s), 1Tb/s 32QAM (32.0 Tb/s) and 1.2Tb/s 64QAM (38.4 Tb/s).

All-optical clock recovery for signal processing and regeneration

Self pulsating DFB lasers are developed for all-optical clock recovery. The system performance of these devices is demonstrated and their ultra high speed potential is pointed out.

Networking aspects for next-generation elastic optical interfaces

Next-generation elastic optical interfaces will support a wide range of line rates and modulation formats. Such transmission schemes enable doubling of the channel capacity at the expense of a lower reach, whereas a flexible DWDM grid supports the transport of multiple optical signals within a single frequency slot by packing them closely, thus saving spectral resources. The resulting multitude of options on the line side provides network planners the capability to derive the most suitable one for each individual path inside the network. However, planning and operational complexity should not be overlooked, since aspects such as added spectrum fragmentation can hamper the expected network improvements. This paper investigates how to obtain the best compromise between harnessing the main benefits of next-generation optical interfaces, while keeping the complexity of the underlying system at a reasonable level. In particular, we define a novel network spectral efficiency (SE) metric that enables, on one hand, to highlight the relevance of supporting a flexible grid to improve SE and, on the other hand, to demonstrate that the grid granularity can be based on coarser 50 GHz increments without major penalties. The effectiveness of this parameter has been verified by considering two reference network topologies. Finally, the paper also discusses how future optical interface technology developments will shape network design.

Dynamic behavior of optically clocked 4-mm UL-SOA at 40 Gbit/s

The dynamic characteristics of an ultra-long semiconductor optical amplifier (UL-SOA) with a length of 4 mm are investigated experimentally. An optically clocked technique is applied for suppressing the patterning effects in an SOA and for exploiting effectively the fast intra-band effects. The gain dynamic in the UL-SOAs is here stabilised by a sinusoidal optical clock signal which is additionally injected into the device, bit interleaved with a PRBS data signal. The optimal operation condition of the novel scheme concerning power levels of the RZ data signal and clock signal are analysed in detail at 40 Gbit/s. We use the ultra-fast nonlinearities in the UL-SOAs for regenerating of a 40 Gbit/s data signal in amplitude, time and pulse shape. The 40 GHz recovered clock signal in the optically clocked 3R regenerator is generated by a self-pulsating three section DFB laser. An excellent regenerative performance even for strong degraded data signals is demonstrated.

9.6Tb/s CP-QPSK Transmission Over 6500 km of NZ-DSF With Commercial Hybrid Amplifiers

We experimentally demonstrate, for the first time to the best of our knowledge, an ultralong-haul dense wavelength division multiplexed transmission of 96 × 100Gb/s coherent polarization multiplexed quadrature phase-shifted keying transponders over ITU-T G.655 nonzero dispersion-shifted large effective area fibers (NZ-DSF) with an effective core area of 72 μm2, employing both commercial erbium-doped fiber amplifiers (EDFA) and hybrid EDFA + Raman amplification systems. Using the state-of-the-art digital pulse shaping and digital preemphasis algorithms, we report ~1.5dB back-toback optical signal-to-noise ratio penalty at pre forward error correction (FEC) bit error rate (BER) threshold (3.8 × 10-2), with respect to theoretical performance. In particular, we demonstrate ~6500km transmission across the entire C-band, at pre-FEC BER of 3.8 × 10-2, employing EDFA + backward Raman amplification-where the central channel (1552.2nm) had sufficient margin to enable transmission of up to ~8000km. Furthermore, we report that hybrid amplification enables up to ~60% improvement in maximum transmission reach, compared to EDFA based links. To the best of our knowledge, a record capacity-distance product of ~62.4 Pb/s·km is achieved for NZ-DSF-an 11-fold increase, compared with the previous literature.

Multi-flex field trial over 762km of G.652 SSMF using programmable modulation formats up to 64QAM

We demonstrate next-generation network upgrade scenarios using flexi-format (PM-QPSK→PM-64QAM) and flexi-rate (100G→300G) transmission over field-deployed fiber (762km). The back-to-back penalties are limited to ~2.6dB, whereas after transmission, available margin in excess of ~7.6dB is reported.