Spectral Efficient Coding Schemes in Optical Communications

Lotz, T.; Sauer-Greff, W.; Urbansky, R.

doi:10.5923/j.ijoe.20120204.01

Cited by 2 publications

(2 citation statements)

References 31 publications

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“…A less powerful form of multiplexing is offered by using schemes that do not permit efficient signal routing, adding, and dropping, but do allow detection of signals in different channels. Examples of this are optical code-division multiple access (OCDMA), quadrature amplitude modulation (QAM), and optical orthogonal frequency-division multiplexing (OFDM) [1,2]. In those cases the detector has special capabilities that allow the separate detection of signals associated with different channels, but cannot efficiently separate them into distinct spatial channels for routing.…”

Section: Introductionmentioning

confidence: 99%

Temporal mode selectivity by frequency conversion in second-order nonlinear optical waveguides

Reddy¹,

Raymer²,

McKinstrie³

et al. 2013

Opt. Express

109

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Abstract:We explore theoretically the feasibility of using frequency conversion by sum-or difference-frequency generation, enabled by threewave-mixing, for selectively multiplexing orthogonal input waveforms that overlap in time and frequency. Such a process would enable a drop device for use in a transparent optical network using temporally orthogonal waveforms to encode different channels. We model the process using coupled-mode equations appropriate for wave mixing in a uniform secondorder nonlinear optical medium pumped by a strong laser pulse. We find Green functions describing the process, and employ Schmidt (singularvalue) decompositions thereof to quantify its viability in functioning as a coherent waveform discriminator. We define a selectivity figure of merit in terms of the Schmidt coefficients, and use it to compare and contrast various parameter regimes via extensive numerical computations. We identify the most favorable regime (at least in the case of no pump chirp) and derive the complete analytical solution for the same. We bound the maximum achievable selectivity in this parameter space. We show that including a frequency chirp in the pump does not improve selectivity in this optimal regime. We also find an operating regime in which high-efficiency frequency conversion without temporal-shape selectivity can be achieved while preserving the shapes of a wide class of input pulses. The results are applicable to both classical and quantum frequency conversion.

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Section: Introductionmentioning

confidence: 99%

Temporal mode selectivity by frequency conversion in second-order nonlinear optical waveguides

Reddy¹,

Raymer²,

McKinstrie³

et al. 2013

Opt. Express

109

View full text Add to dashboard Cite

show abstract

“…This paves the way for a number of complex modulation formats for increased spectral efficiency in transmission systems, for example, phaseshift keying [87], differential phase-shift keying [88], quadrature phase-shift keying [89] and quadrature amplitude modulation [89]. All these are likely to increase the spectral efficiency of a communication link [90][91][92].…”

Section: Graphene-based Modulatorsmentioning

confidence: 99%

Graphene-based integrated photonics for next-generation datacom and telecom

Romagnoli¹,

Sorianello²,

et al. 2018

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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...

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Spectral Efficient Coding Schemes in Optical Communications

Cited by 2 publications

References 31 publications

Temporal mode selectivity by frequency conversion in second-order nonlinear optical waveguides

Temporal mode selectivity by frequency conversion in second-order nonlinear optical waveguides

Graphene-based integrated photonics for next-generation datacom and telecom

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