Energy considerations regarding next generation passive optical networks

The increasing demand for faster broadband access requires the development of next-generation Passive Optical Networks (PONs) operating at very high bit rates (e.g. 40 Gb/s). On the same time, energy efficiency in Information and Communication Technology (ICT) infrastructure has become a very important topic. In this paper, several proposed solutions for future high-speed PONs, such as coherent and incoherent multilevel signaling, wavelength-multiplexed On-Off Keying (OOK) and Orthogonal Frequency Division Multiplexing (OFDM), are examined with regards to the energy consumption of the system, with results indicating that the necessary bit rates can be provided without sacrificing energy efficiency

Multi-level modulation formats for optical access networks

There is growing demand for higher bit rates at the access domain. The most promising and future-proof technology for providing end users with high bandwidth is Passive Optical Networks (PON). In order to provide these higher bit rates, the use of multi-level modulation has been proposed. By moving to multi-level signals, low speed electronics can be used, with some added complexity to the optical part. This paper investigates the performance of incoherent multi-level modulation formats (in particular QAM and DQPSK) in bidirectional PONs. The simulation results indicate that incoherent QAM is a strong candidate for future PONs

2 x 10 Gbit/s WDM 1310-nm optical transmissin over 63.5-km standard single-mode fiber using optical preamplifiers

Twenty Gbit/s transmission over 63.5 km SMF at 1310 nm is reported by using two channel 10 Gbit/s wavelength (de)multiplexing (¿¿=1.5 nm). Two 1310 nm SL-MQW semiconductor optical amplifiers are utilized for loss compensation and sensitivity improvement. For the 1310 nm wavelength domain, a record bitrate x distance product of 1.27 Tbit/s.km has been obtained. Crosstalk penalties are identified, and the feasibility of an extension up to at least four, 10 Gbit/s channels is discusse

On the effect of receiver impairments on incoherent QAM systems

Incoherent QAM is a differentially detected, multilevel modulation format that can improve spectral efficiency in optical communication systems. The effect of three receiver impairments on the performance of an incoherent QAM system is assessed in this paper for the first time. Specifically, the impairments studied are an unbalanced Mach-Zehnder Interferometer (MZI,), the phase detuning of the MZI and the amplitude imbalance of the Balanced Photodetectors (BPD). Extensive simulations were carried out and results indicate that incoherent QAM is quite robust in respect to the aforementioned impairments, with the phase detuning being the most critical parameter leading to peiformance degradatio

Clock recovery and demultiplexing performance of 160-Gb/s OTDM field experiments

Clock recovery (CR) from a 160-Gb/s data signal is demonstrated using a single unidirectional electroabsorption modulator in a cost-effective phase-locked loop configuration consisting entirely of commercially available components. The CR exhibits a root mean square time jitter of 205 fs, a holding range of 10 MHz, a wavelength-independent performance of 10 nm, and an input dynamic range of 10 dB. Demultiplexing experiments of transmitted 160-Gb/s data through installed fiber links over 275.4 km verified the excellent performance of the proposed CR. All 16 10-Gb/s channels were demultiplexed error-free

Study on the limits of all-optical time domain demultiplexing using cross absorption modulation in an electroabsorption modulator

A theoretical and experimental assessment of the performance of an all-ticaldemultiplexer based on cross-absorption modulation in an electroabsorption modulator is presented. Simulations are described for demultiplexing from 160 Gbit/s to a 40 or 10 Gbit/s base rate. Experimental results are presented for demultiplexing to a base rate of 10 Gbit/s from an optical time-domain multiplexing rate of 80 with a bit error rate (BER) ,1029 and 160 Gbit/s with a BER ’1027

Semiconductor optical amplifiers and raman amplification for 1310-nm wavelength division multiplexed transmission

We investigate the utilization of semiconductor optical amplifiers (SOAs) and quantum-dot laser-based Raman amplifiers in high-capacity dense wavelength division multiplexed (DWDM) 1310-nm transmission systems. Performed simulations showed that in a 10×40  Gbit/s 10×40  Gbit/s system, the utilization of a single Raman amplifier in a back-propagation scheme can extend the maximum error-free (bit error rate <10 −9 <10−9 ) transmission distance by approximately 25 km in comparison with the same system utilizing only an SOA used as a preamplifier. We successfully applied a Raman amplifier in an 8×2×40  Gbit/s 8×2×40  Gbit/s 1310-nm polarization multiplexed (PolMux) DWDM transmission over 25 km. Conducted experiments showed that the utilization of a Raman amplifier in this system leads to 4-dB improvement of the average channel sensitivity in comparison to the same system utilizing SOAs. This sensitivity improvement can be translated into a higher power budget. Moreover, lower input optical power in a system utilizing a Raman amplifier reduces the four-wave mixing interactions. The obtained results prove that Raman amplification can be successfully applied in 1310-nm high-capacity transmission systems, e.g., to extend the reach of 400G and 1T Ethernet systems