Enrico Ghillino

Raman-assisted transmission of Nyquist-WDM PM-16QAM channels at 240 Gbps on PSCF

We evaluate by simulation the maximum reachable distance of ten Nyquist-WDM channels at 240 Gbps based on PM-16QAM in PSCF links. Operating with a channel spacing of only 1.1·RS and using Raman amplification, we demonstrate a maximum reachable distance of 3,600 km. Moreover, we make an assessment of the scaling of nonlinear impairments in the case of using hybrid EDFA/Raman amplification.

100-Gb/s PAM4 link modeling incorporating MPI

100-Gb/s PAM4 optical links based on cascaded silicon modulators and DSP-based receivers are comprehensively modeled. Simulation results highlight the impact of key impairments such as MPI, RIN, passive loss, and receiver noise.

Mixed-level optical-system simulation incorporating component-level modeling of interface elements

While system-level simulation can allow designers to assess optical system performance via measures such as signal waveforms, spectra, eye diagrams, and BER calculations, component-level modeling can provide a more accurate description of coupling into and out of individual devices, as well as their detailed signal propagation characteristics. In particular, the system-level simulation of interface components used in optical systems, including splitters, combiners, grating couplers, waveguides, spot-size converters, and lens assemblies, can benefit from more detailed component-level modeling. Depending upon the nature of the device and the scale of the problem, simulation of optical transmission through these components can be carried out using either electromagnetic device-level simulation, such as the beampropagation method, or ray-based approaches. In either case, system-level simulation can interface to such componentlevel modeling via a suitable exchange of optical signal data. This paper presents the use of a mixed-level simulation flow in which both electromagnetic device-level and ray-based tools are integrated with a system-level simulation environment in order to model the use of various interface components in optical systems for a range of purposes, including, for example, coupling to and from optical transmission media such as single- and multimode optical fiber. This approach enables case studies on the impact of physical and geometric component variations on system performance, and the sensitivity of system behavior to misalignment between components.

Improved tolerance to the combined effect of in-band crosstalk and chromatic dispersion in partial DPSK systems

We use simulations to investigate the influence of the value of the differential delay of the Mach-Zehnder interferometer (MZI) demodulator in differential phase-shift-keyed (DPSK) systems when the system is limited by the combined effect of chromatic dispersion and in-band crosstalk. It is found that the dispersion and filtering tolerance improvement which is realized when the delay is less than one bit-period is preserved in systems with strong in-band crosstalk.

Physical layer modeling of passive optical networks

Passive Optical Network (PON) based access architecture is the most favored choice for delivery of triple-play services today. This paper reviews various PON technologies, requirements, challenges and trade-offs involved in modeling and design optimizations of PON systems and sub-systems, mainly from the physical layer perspective.

Using system simulation to evaluate design choices for automotive ethernet over plastic optical fiber

The growing bandwidth demands of advanced driver assistance systems (ADAS) and infotainment technologies make Gigabit Ethernet over plastic optical fiber (POF) a natural choice for next-generation automotive data networks, especially in light of the recent approval of the IEEE 802.3bv standard for Gigabit Ethernet transmission over POF. POF-based transmission provides the advantages of low cost, light weight, easy termination, durability, and immunity to electromagnetic interference (EMI), while Gigabit Ethernet extends the current maximum data rate of 150 Mb/s provided by Media Oriented Systems Transport (MOST). Thus, we examine important design choices that impact the performance of POF-based automotive data links for data rates up to and beyond 1 Gb/s and different choices of modulation format, including NRZ and PAM-n. Because simulation is an efficient and cost-effective solution for studying the complex interplay of multiple design choices without requiring physical prototypes, we base our analysis on a comprehensive modeling framework for optical communication systems incorporating large-core step-index fiber and fiber-to-fiber connectors. We study anticipated system performance in terms of bandwidth and BER for different choices of link length and connector count, including the IEEE 802.3bv targets of 15 meters with four connectors and 40 meters with no connectors. In addition, we consider the impact of connector misalignments (both lateral and longitudinal) and source launch profile (measured in terms of its encircled angular flux, or EAF), which also directly affect link bandwidth.

Simulation of silicon photonic coherent PM-QPSK transceivers using microring modulators

Silicon photonic components are key enablers for low-cost, compact, and reduced power-consumption coherent transceivers. This paper discusses models used to analyze the performance of silicon photonic ring modulators in coherent links, and presents simulation results for 32- and 16-Gbaud PM-QPSK back-to-back transceivers incorporating these modulators in comparison with designs using LiNbO3 MZMs. While the penalty at 32 Gbaud is high, at 16 Gbaud the ring modulator performance approaches that of the MZM, with a sensitivity penalty of only 1.3 dB. Our results also show the strong temperature sensitivity of the ring modulator.

Modeling software for optical broadband access network design and optimization

Designing broadband access networks involves selecting the topology that satisfies the network requirements, and comparing the performance of different what-if scenarios in order to achieve the optimal network layout. Modeling software tools are instrumental for each phase of the design cycle and help answering to complex questions such as what is the impact of single- and multi-mode fiber linear and nonlinear effects, what is maximum fiber length before eye closure, how many regenerators are needed and where they have to be placed. This paper shows through a series of examples how modeling tools can be used for single- and multi-mode broadband access network design and planning.