Graphene is an ideal material for optoelectronic applications. Its photonic properties give several advantages and complementarities over Si photonics. For example, graphene enables both electro-absorption and electro-refraction modulation with an electro-optical index change exceeding 10 −3 . It can be used for optical add-drop multiplexing with voltage control, eliminating the current dissipation used for the thermal detuning of microresonators, and for thermoelectric-based ultrafast optical detectors that generate a voltage without transimpedance amplifiers. Here, we present our vision for graphene-based integrated photonics. We review graphene-based transceivers and compare them with existing technologies. Strategies for improving power consumption, manufacturability and wafer-scale integration are addressed. We outline a roadmap of the technological requirements to meet the demands of the datacom and telecom markets. We show that graphene based integrated photonics could enable ultrahigh spatial bandwidth density , low power consumption for board connectivity and connectivity between data centres, access networks and metropolitan, core, regional and long-haul optical communications.Photonics is poised to play an increasingly important role in ICT ( Fig. 1a), since the fixed high capacity links are largely based on photonic technologies. Photonic devices need to support ultra-large bandwidth operation, for example, 200 Tb s−1 in a single fibre[9] and >10 Tb s −1 cm −2 in integrated Si photonics chips [10]. To achieve this, the key components of Si photonics, photodetectors and modulators, need very high performances in terms of speed (≥25 Gb s −1 ), footprint (<1 mm 2 ), insertion loss (<4 dB), manufacturability (>10 6 pieces per year) and power consumption (<1 pJ bit −1 ). To date, these requirements have not been fulfilled in one system [11]. Furthermore, in terms of production volumes, photonics is not yet comparable to microelectronics [12], even if the increase in demand for optical networks would, by 2021, lead to an average global Internet Protocol (IP) traffic of 3.3 ZB (zettabytes), corresponding to an average usage data rate of ~800 Tb s −1 (refs[13,14]). In the context of the IoT[7], other applications, including infrared (IR) sensors, biosensors, environmental sensors, metrology, quantum communications and machine vision, will require even larger production volumes [13,15].The telecom network can be divided into three segments: access, aggregation and core (Fig. 1a). The access network is the interface between subscribers and the immediate service provider. The aggregation network aggregates all the input data streams from tributary access networks, converging towards the higher-level core network. The aggregation network includes local and metropolitan networks, which then converge to regional networks. A local area network (LAN) interconnects computers within a limited area, such as a residence, school, laboratory, university or office building. A metropolitan area network (MAN) interconnects us...

No abstract

This article reports the work on next generation transponders for optical networks carried out within the last few years. A general architecture supporting super-channels (i.e., optical connections composed of several adjacent subcarriers) and sliceability (i.e., subcarriers grouped in a number of independent super-channels with different destinations) is presented. Several transponder implementations supporting different transmission techniques are considered, highlighting advantages, economics, and complexity. Discussions include electronics, optical components, integration, and programmability. Application use cases are reported

No abstract

In this work we detail the strategies adopted in the European research project IDEALIST to overcome the predicted data plane capacity crunch in optical networks. In order for core and metropolitan telecommunication systems to be able to catch up with Internet traffic, which keeps growing exponentially, we exploit the elastic optical networks paradigm for its astounding characteristics: flexible bandwidth allocation and reach tailoring through adaptive line rate, modulation formats, and spectral efficiency. We emphasize the novelties stemming from the flex-grid concept and report on the corresponding proposed target network scenarios. Fundamental building blocks, like the bandwidth-variable transponder and complementary node architectures ushering those systems, are detailed focusing on physical layer, monitoring aspects, and node architecture design

A multiflow transponder in flex-grid optical networks has recently been proposed as a transponder solution to generate multiple optical flows (or subcarriers). Multiflow transponders support high-rate super-channels (i.e., connection composed of multiple corouted subcarriers contiguous in the spectrum) and sliceability; i.e., flows can be flexibly associated to the incoming traffic requests, and, besides composing a super-channel, they can be directed toward different destinations. Transponders supporting sliceability are also called sliceable transponders or sliceable bandwidth variable transponders (SBVTs). Typically, in the literature, SBVTs have been considered composed of multiple laser sources (i.e., one for each subcarrier). In this paper, we propose and evaluate a novel multirate, multimodulation, and code-rate adaptive SBVT architecture. Subcarriers are obtained either through multiple laser sources (i.e., a laser for each subcarrier) or by exploiting a more innovative and cost-effective solution based on a multiwavelength source and micro-ring resonators (MRRs). A multiwavelength source is able to create several optical subcarriers from a single laser source. Then, cascaded MRRs are used to select subcarriers and direct them to the proper modulator. MRRs are designed and analyzed through simulations in this paper. An advanced transmission technique such as time frequency packing is also included. A specific implementation of a SBVT enabling an information rate of 400 Gb∕s is presented considering standard 100 GbE interfaces. A node architecture supporting SBVT is also considered. A simulation analysis is carried out in a flex-grid network. The proposed SBVT architecture with a multiwavelength source permits us to reduce the number of required lasers in the network.

No abstract

Abstract:We study the frequency chirp properties of graphene-on-silicon electro-absorption modulators (EAMs). By experimentally measuring the chirp of a 100 µm long single layer graphene EAM, we show that the optoelectronic properties of graphene induce a large positive linear chirp on the optical signal generated by the modulator, giving rise to a maximum shift of the instantaneous frequency up to 1.8 GHz. We exploit this peculiar feature for chromatic-dispersion compensation in fiber optic transmission thanks to the pulse temporal lensing effect. In particular, we show dispersion compensation in a 10Gb/s transmission experiment on standard single mode fiber with temporal focusing distance (0-dB optical-signal-to-noise ratio penalty) of 60 km, and also demonstrate 100 km transmission with a bit error rate largely lower than the conventional Reed-Solomon forward error correction threshold of 10 −3 .