Michael Eiselt

Analysis of intensity interference caused by cross-phase modulation in dispersive optical fibers

Under a set of broadly justified simplifying assumptions, an analytical approach to the problem of cross phase modulation in optical fibers is presented. Simple analytical expressions describing intensity interference caused by cross-phase modulation (XPM) are derived. It turns out that within a physically realizable range of parameters the power penalties induced by XPM have a linear dependence on the power of the interfering signal. Examples of specific systems are presented and discussed.

Cost and energy consumption analysis of advanced WDM-PONs

Next-generation access systems will have to provide bandwidths in excess of 100 Mb/s per residential customer, in conjunction with high customer count and high maximum reach. Potential systems solutions include several variants of WDM-PONs. These systems, however, differ significantly in their cost (capital expenditures) and energy consumption potential. We compare several WDM-PON concepts, including hybrid WDM-PON with integrated per-wavelength multiple access, with regard to these parameters. We also show the impact and importance of generic next-generation bandwidth and reach requirements.

A dynamic impairment-aware networking solution for transparent mesh optical networks

Core networks of the future will have a translucent and eventually transparent optical structure. Ultra-high-speed end-to-end connectivity with high quality of service and high reliability will be realized through the exploitation of optimized protocols and lightpath routing algorithms. These algorithms will complement a flexible control and management plane integrated in the proposed solution. Physical layer impairments and optical performance are monitored and incorporated in impairment-aware lightpath routing algorithms. These algorithms will be integrated into a novel dynamic network planning tool that will consider dynamic traffic characteristics, a reconfigurable optical layer, and varying physical impairment and component characteristics. The network planning tool along with extended control planes will make it possible to realize the vision of optical transparency. This article presents a novel framework that addresses dynamic cross-layer network planning and optimization while considering the development of a future transport network infrastructure.

Adaptive Data Rates for Flexible Transceivers in Optical Networks

Efforts towards commercializing higher-speed optical transmission have demonstrated the need for advanced modulation formats, several of which require similar transceiver hardware architecture. Adaptive transceivers can be built to have a number of possible operational configurations selected by software. Such software-defined transceiver configurations can create specific modulation formats to support sets of data rates, corresponding tolerances to system impairments, and sets of electronic digital signal processing schemes chosen to best function in a given network environment. In this paper, we discuss possibilities and advantages of reconfigurable, bit-rate flexible transceivers, and their potential applications in future optical networks.

Experimental comparison of WDM system capacity in conventional and nonzero dispersion shifted fiber

A primary consideration in designing new backbone optical network segments is the total data capacity of each fiber span. We compare the wavelength-division-multiplexed capacity of conventional single-mode fiber (SMF) and nonzero dispersion shifted fiber by measuring performance versus channel spacing in 4/spl times/80 km transmission of five 10 Gb/s channels at the nominal commercial erbium-doped fiber amplifier power specification of 9 dBm/ch. The achievable capacity is found to be more than four times greater in conventional SMF.

Access Networks Based on Tunable Lasers

State-of-the-art, prospects, and challenges of next-generation optical access technology based on tunable lasers are discussed. These considerations can also be applied to various backhaul and mobile fronthaul applications since these have similar characteristics and requirements, and have to share at least part of the optical distribution networks. Potential advantages of tunable lasers over competing approaches (e.g., seeded reflective transmitters) include higher bit-rate × reach products and better tolerance to reflections in the fiber plant. Today, the main issue is still the lack of available low-cost tunables with sufficient tuning range and launch power. However, significant progress has been made in the last few years to bring such lasers closer to commercialization. In this paper, we will review low-cost tunable laser approaches and report on latest technical results. We will also give an overview on current standardization activities and give an outlook on next-generation optical access, backhaul and fronthaul networks which also support active-site consolidation.

Crosstalk in WDM systems caused by cross-phase modulation in erbium-doped fiber amplifiers

We show experimentally that cross-phase modulation (XPM) in erbium-doped fiber amplifiers (EDFAs) may cause crosstalk between channels transmitted over conventional fiber. As this effect is constant over a large range of wavelength separations, it is capable of creating interference between a large number of channels. In some important cases, XPM originating in the EDF may become comparable in significance to that originating in the transmission fiber.

DMT Modulation With Adaptive Loading for High Bit Rate Transmission Over Directly Detected Optical Channels

In this paper, we present the design and analysis of an adaptive cost-effective discrete multitone transponder (DMT) using direct detection (DD) suitable for data center interconnections. Levin Campello margin adaptive (LC-MA) algorithm is applied to the transponder digital signal processing modules to enhance fiber chromatic dispersion (CD) resilience, while achieving high-data rate transmission. The bit error rate (BER) performance and the rate/distance adaptive capabilities of the proposed transponder have been numerically analyzed and compared to bandwidth variable uniform loading, taking into account the transmission impairments at the varying of the fiber length. Specifically, the performance of the designed transponder has been assessed from 20 to 112 Gb/s, extending the achievable reach at 50 Gb/s beyond 80 km of standard single mode fiber (SSMF). The numerical simulations have been compared with experimental results, evidencing good agreement in presence of transmission impairments.

Field trial of a quantum secured 10 Gb/s DWDM transmission system over a single installed fiber

We present results from the first field-trial of a quantum-secured DWDM transmission system, in which quantum key distribution (QKD) is combined with 4 × 10 Gb/s encrypted data and transmitted simultaneously over 26 km of field installed fiber. QKD is used to frequently refresh the key for AES-256 encryption of the 10 Gb/s data traffic. Scalability to over 40 DWDM channels is analyzed.

Bidirectional ULH transmission of 160-gb/s full-duplex capacity over 5000 km in a fully bidirectional recirculating loop

A bidirectional transmission system with 16 10-Gb/s dense wavelength-division-multiplexing channels on 32 wavelengths is demonstrated over 5000 km (50/spl times/100 km) of nonzero dispersion-shifted fiber in a fully bidirectional recirculating loop, for a full-duplex capacity-distance product of 800 Tb/s /spl middot/ km. This bidirectional architecture shares the optical fiber, optical amplifiers, dispersion compensators, and dynamic gain equalizers between the two traffic directions, significantly reducing the common optical equipment costs of ultralong-haul transmission systems.