Researchers demonstrate the ability to multiplex and transfer data between twisted beams of light with different amounts of orbital angular momentum — a development that provides new opportunities for increasing the data capacity of free-space optical communications links.

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Terabit free-space data transmission employing orbital angular momentum multiplexing

This Review summarizes the simultaneous transmission of several independent spatial channels of light along optical fibres to expand the data-carrying capacity of optical communications. Recent results achieved in both multicore and multimode optical fibres are documented.

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Space-division multiplexing in optical fibres

Nonlinear photonic chips can generate and process signals all-optically with far superior performance to that possible electronically — particularly with respect to speed. Although silicon-on-insulator has been the leading platform for nonlinear optics, its high two-photon absorption at telecommunication wavelengths poses a fundamental limitation. We review recent progress in non-silicon CMOS-compatible platforms for nonlinear optics, with a focus on Si3N4 and Hydex®. These material systems have opened up many new capabilities such as on-chip optical frequency comb generation and ultrafast optical pulse generation and measurement. We highlight their potential future impact as well as the challenges to achieving practical solutions for many key applications. This article reviews recent progress in the use of silicon nitride and Hydex as non-silicon-based CMOS-compatible platforms for nonlinear optics. New capabilities such as on-chip optical frequency comb generation, ultrafast optical pulse generation and measurement using these materials, and their potential future impact and challenges are covered.

New CMOS-compatible platforms based on silicon nitride and hydex for nonlinear optics

Today cross-cutting approaches, where molecular engineering and clever processing are synergistically coupled, allow the chemist to tailor complex hybrid systems of various shapes with perfect mastery at different size scales, composition, functionality, and morphology. Hybrid materials with organic–inorganic or bio–inorganic character represent not only a new field of basic research but also, via their remarkable new properties and multifunctional nature, hybrids offer prospects for many new applications in extremely diverse fields. The description and discussion of the major applications of hybrid inorganic–organic (or biologic) materials are the major topic of this critical review. Indeed, today the very large set of accessible hybrid materials span a wide spectrum of properties which yield the emergence of innovative industrial applications in various domains such as optics, micro-electronics, transportation, health, energy, housing, and the environment among others (526 references).

Applications of advanced hybrid organic–inorganic nanomaterials: from laboratory to market

The nonlinearities in silicon are diverse. This Review covers the wealth of nonlinear effects in silicon and highlights the important applications and technological solutions in nonlinear silicon photonics. The increasing capability for manufacturing a wide variety of optoelectronic devices from polymer and polymer–silicon hybrids, including transmission fibre, modulators, detectors and light sources, suggests that organic photonics has a promising future in communications and other applications.

Nonlinear silicon photonics

Recently, there is a great interest in pushing communication technologies to 100 Gb/s. However, there are still many challenges to perform high speed (> 40 Gb/s) clock and data recovery, and data time-division-multiplexing (TDM). Here, we propose and numerically analyze an asynchronous optical packet retimer using parabolic or sinusoidal phase modulation and linear dispersion. This scheme is named pulse position locking (PPL). Numerical simulation shows that this scheme can effectively resynchronize input signals with arbitrary delays to the local clock, and reduce input jitter. The scheme can also be applied to TDM 10 Gb/s and 40 Gb/s signals to over 100 Gb/s.

http://eprints.aston.ac.uk/18023/1/Time_division_multiplexing.pdf

Time-division-multiplexing using pulse position locking for 100 Gb/s applications.

We experimentally demonstrate phase regeneration of a 40-Gb/s differential phase shift keying (DPSK) signal in a 1.7-m long highly nonlinear lead silicate W-type fiber using a degenerate two-pump phase-sensitive amplifier (PSA). Results show an improvement in the Error Vector Magnitude (EVM) and a reduction of almost a factor of 2 in the phase noise of the signal after regeneration for various noise levels at the input.

Phase regeneration of DPSK signals in a highly nonlinear lead-silicate W-type fiber

We experimentally demonstrate a means to selectively enhance wavelength conversion of WDM channels on a 100 GHz grid exploiting nonlinear effects between the spatial modes of a few mode fiber. The selectivity of parametric gain is obtained by dispersion design of the fiber such that the inverse group velocity curves of the participating modes are parallel and their dispersion is suitably large. We describe both theoretically and experimentally the observed dependence of the idler gain profile on pump mode (quasi) degeneracy.

Selective wavelength conversion in a few-mode fiber.

Robust, low loss (0.16dB) splicing of hollow core photonic band gap fiber to itself is presented. Modal content is negligibly affected by splicing, enabling penalty-free 40Gbit/s data transmission over > 200m of spliced PBGF.

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Robust low loss splicing of hollow core photonic bandgap fiber to itself

We report on the design, fabrication and characterization of a single-mode W-type lead-silicate glass fibre with flattened and near-zero dispersion profile at telecom wavelengths and high nonlinearity of 820W−1 km−1 at 1.55µm.

/pdf/a-single-mode-high-index-contrast-lead-silicate-glass-fibre-xppy2amysi.pdf

Francesca Parmigiani

Papers

Time-division-multiplexing using pulse position locking for 100 Gb/s applications.

Phase regeneration of DPSK signals in a highly nonlinear lead-silicate W-type fiber

Selective wavelength conversion in a few-mode fiber.

Robust low loss splicing of hollow core photonic bandgap fiber to itself

A single-mode, high index-contrast, lead silicate glass fibre with high nonlinearity, broadband near-zero dispersion at telecommunication wavelengths