Changing evolution of optical communication systems at the network edges.

Metro and data center networks are growing rapidly, while global fixed Internet traffic growth shows evidence of slowing. An analysis of the distribution of network capacity versus distance reveals capacity gaps in networks important to wireless backhaul networks and cloud computing. These networks are built from layers of electronic aggregation switches.

Dual-wavelength source based optical circuit switching and wavelength reconfiguration in multi-hop ROADM systems.

Using a dual-wavelength source, a single optical signal is distributed over two wavelengths. This approach is used to reduce power excursions due to optical circuit switching in ROADM systems. In a multi-hop optical transmission system with 100Gbps PM-QPSK signals switched over five ROADMs and 265 km of single mode fiber (SMF), power excursions are kept within ± 0.

Performance optimization of PM-16QAM transmission system enabled by real-time self-adaptive coding.

We experimentally demonstrate self-adaptive coded 5×100  Gb/s WDM polarization multiplexed 16 quadrature amplitude modulation transmission over a 100 km fiber link, which is enabled by a real-time control plane. The real-time optical signal-to-noise ratio (OSNR) is measured using an optical performance monitoring device. The OSNR measurement is processed and fed back using control plane logic and messaging to the transmitter side for code adaptation, where the binary data are adaptively encoded with three types of low-density parity-check (LDPC) codes with code rates of 0.

Energy efficiency of optical grooming of QAM optical transmission channels.

Analysis of the energy use for optical grooming of quadrature amplitude modulated signals in optical transmission systems is used to determine the potential efficiency benefits. An energy model is developed for both optical and electronic grooming and used to study the relative efficiency for three different network scenarios. The energy efficiency is evaluated considering both coherent and direct detection transceivers including power management strategies.

Energy challenges in optical access and aggregation networks.

Scalability is a critical issue for access and aggregation networks as they must support the growth in both the size of data capacity demands and the multiplicity of access points. The number of connected devices, the Internet of Things, is growing to the tens of billions. Prevailing communication paradigms are reaching physical limitations that make continued growth problematic.

Methodologies for assessing the use-phase power consumption and greenhouse gas emissions of telecommunications network services.

Internet traffic has grown rapidly in recent years and is expected to continue to expand significantly over the next decade. Consequently, the resulting greenhouse gas (GHG) emissions of telecommunications service-supporting infrastructures have become an important issue. In this study, we develop a set of models for assessing the use-phase power consumption and carbon dioxide emissions of telecom network services to help telecom providers gain a better understanding of the GHG emissions associated with the energy required for their networks and services.

Effect of cross-phase-modulation-induced polarization scattering on optical polarization mode dispersion compensation in wavelength-division-multiplexed systems.

Interchannel cross-phase-modulation-induced polarization scattering (XPMIPS) and its effect on the performance of optical polarization mode dispersion (PMD) compensation in wavelength-division-multiplexed (WDM) systems are studied. The level of XPMIPS in long-haul WDM transmission systems is theoretically quantified, and its effect on optical PMD compensation is evaluated with numerical simulations. We show that in 10-Gbit/s ultra-long-haul dense WDM systems XPMIPS could reduce the PMD compensation efficiency by 50%, whereas for 40-Gbit/s systems the effect of XPMIPS is smaller.

Polarization-dependent noise in photon-number squeezed light generated by quantum-well lasers.

Amplitude noise spectra from the nonclassical output of an injection-locked low-temperature quantum-well laser analyzed along orthogonal polarization axes reveals correlated polarization-dependent noise. Using polarization-preserving balanced homodyne detection to suppress these effects, we demonstrate photon-number fluctuations 4.5 dB below the semiclassical shot-noise limit (within 95% of the expected squeezing based on the device efficiency).

Room-temperature amplitude-squeezed light from an injection-locked quantum-well laser with a time-varying drive current.

We demonstrate the conversion of a time-varying (50-400-MHz) electrical current into an optical power with fidelity 0.8 dB (1.35 dB after correction for detection efficiency) beyond the standard quantum limit by drive-current modulation of an injection-locked quantum-well laser.