This paper presents an overview of integrated optics routing and coupling devices based on multimode interference. The underlying self-imaging principle in multimode waveguides is described using a guided mode propagation analysis. Special issues concerning the design and operation of multimode interference devices are discussed, followed by a survey of reported applications. It is shown that multimode interference couplers offer superior performance, excellent tolerance to polarization and wavelength variations, and relaxed fabrication requirements when compared to alternatives such as directional couplers, adiabatic X- or Y-junctions, and diffractive star couplers. >

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Optical multi-mode interference devices based on self-imaging: principles and applications

Recent advances in developing nonlinear optical techniques for processing serial digital information at high speed are reviewed. The field has been transformed by the advent of semiconductor nonlinear devices capable of operation at 100 gigabits per second and higher, well beyond the current speed limits of commercial electronics. These devices are expected to become important in future high-capacity communications networks by allowing digital regeneration and other processing functions to be performed on data signals “on the fly” in the optical domain.

https://science.sciencemag.org/content/sci/286/5444/1523.full.pdf

Nonlinear Optics for High-Speed Digital Information Processing.

Semiconductor optical amplifiers are useful building blocks for all-optical gates as wavelength converters and OTDM demultiplexers. The paper reviews the progress from simple gates using cross-gain modulation and four-wave mixing to the integrated interferometric gates using cross-phase modulation. These gates are very efficient for high-speed signal processing and open up interesting new areas, such as all-optical regeneration and high-speed all-optical logic functions.

/pdf/semiconductor-optical-amplifier-based-all-optical-gates-for-4wdu6yc0vj.pdf

Semiconductor optical amplifier-based all-optical gates for high-speed optical processing

Recent progress in optical time-division-multiplexed (TDM) transmission technologies is reviewed including optical short pulse generation, time-division multiplexing/demultiplexing, timing extraction, and waveform measurement. The latest 400-Gbit/s transmission experiments based on optical signal processing are presented and the possibility of terabit/second TDM transmission is discussed.

Ultrahigh-speed optical time-division-multiplexed transmission technology based on optical signal processing

Recent progress in the use of semiconductor laser amplifiers (SLA's) for high-speed all-optical switching is reviewed. We show that, despite SLA's having lifetimes of ⩾100 ps, they are, to date, the most promising material system for all-optical ultrafast signal processing. We highlight the role of SLA carrier dynamics, which permits switching rates faster than the recovery time. Experimental results are presented that imply that switching rates of as much as ∼100 GHz should be possible. Recent experiments are described in which SLA-based switches were incorporated into novel all-optical architectures.

Semiconductor laser amplifiers for ultrafast all-optical signal processing

A Sagnac interferometer consisting of a semiconductor laser amplifier and a 3 dB coupler monolithically integrated within a waveguide loop mirror is fabricated and its application as a 20 Gbit/s all-optical demultiplexer is demonstrated.

Monolithically integrated nonlinear Sagnac interferometer and its application as a 20 Gbit/s all-optical demultiplexer

We report fast 2/spl times/2 Mach-Zehnder optical space switches by using quantum confined Stark effect in InGaAsP-InP multiquantum-well structures that are ultracompact, require low voltages, and employ a simple RF drive with RC time-constant limited lumped electrodes. Cut-off frequencies in excess of 10 GHz are observed suitable for a variety of fast optical switching applications. >

Fast 2 x 2 Mach-Zehnder optical space switches using InGaAsP-InP multiquantum-well structures

Summary form only given. In conclusion, we performed a 40 Gbit/s, 100-km transmission experiment including demultiplexing from 40 Gbit/s to 10 Gbit/s by using a mode-locked semiconductor laser simultaneously as pulse source for the demultiplexer, as all-optical clock recovery, and as detector to synchronize the BER test set.

10 GHz all-optical clock recovery using a mode-locked semiconductor laser in a 40 Gbit/s, 100-km transmission experiment

We report substantial progress in the growth of multi‐quantum‐well electron transfer optical modulator structures by metalorganic vapor phase epitaxy, which is made possible as a consequence of the highly abrupt modulation doping of donors and acceptors in InP‐reservoir and InAlAs‐barrier layers, respectively. Due to a large thermionic emission barrier provided by the type II InP/InAlAs interface, the InGaAsP/InP/InAlAs devices exhibit extremely low leakage current densities. We observe distinct and sharp features related to absorption quenching in differential transmission spectroscopy. Moreover, the saturation intensities of electron transfer modulators are determined. The underlying physical mechanism is discussed.

Electroabsorption and saturation behavior of InGaAsP/InP/InAlAs multiple superlattice electron transfer optical modulator structures

Fast optical space switches are important for a variety of applications in instrumentation and telecommunications, for example. optical-fiber memory in asynchronous-transfer-mode (ATM) systems and time-slot interchangers/demultiplexers in optical time-domain-multiplexing (OTDM) systems. Previously, such devices have been developed primarily with lithium niobate technology.1

N. Agrawal

Papers

Monolithically integrated nonlinear Sagnac interferometer and its application as a 20 Gbit/s all-optical demultiplexer

Fast 2 x 2 Mach-Zehnder optical space switches using InGaAsP-InP multiquantum-well structures

10 GHz all-optical clock recovery using a mode-locked semiconductor laser in a 40 Gbit/s, 100-km transmission experiment

Electroabsorption and saturation behavior of InGaAsP/InP/InAlAs multiple superlattice electron transfer optical modulator structures

2 x 2 optical space switches using InGaAsP/InP MQW structures for 10-GHz Applications