* The only book describing applications of nonlinear fiber optics * Two new chapters on the latest developments: highly nonlinear fibers and quantum applications* Coverage of biomedical applications* Problems provided at the end of each chapterThe development of new highly nonlinear fibers - referred to as microstructured fibers, holey fibers and photonic crystal fibers - is the next generation technology for all-optical signal processing and biomedical applications. This new edition has been thoroughly updated to incorporate these key technology developments.The book presents sound coverage of the fundamentals of lightwave technology, along with material on pulse compression techniques and rare-earth-doped fiber amplifiers and lasers. The extensively revised chapters include information on fiber-optic communication systems and the ultrafast signal processing techniques that make use of nonlinear phenomena in optical fibers.New material focuses on the applications of highly nonlinear fibers in areas ranging from wavelength laser tuning and nonlinear spectroscopy to biomedical imaging and frequency metrology. Technologies such as quantum cryptography, quantum computing, and quantum communications are also covered in a new chapter.This book will be an ideal reference for: RD scientists involved with research on fiber amplifiers and lasers; graduate students and researchers working in the fields of optical communications and quantum information. * The only book on how to develop nonlinear fiber optic applications* Two new chapters on the latest developments; Highly Nonlinear Fibers and Quantum Applications* Coverage of biomedical applications

Applications of nonlinear fiber optics

In this work, we present the study of an asymmetric Mach-Zehnder interferometer using dual core photonic crystal fiber. The asymmetry is obtained through the nonlinearity parameters of the couplers. The study was carried out from the solution of the coupled mode equation, in which we considered the second and third order dispersive effects (GVD and TOD) and non-linear effects (SPM, self-steepening and Raman effect). We analyzed three configurations: a symmetric coupler followed by an asymmetrical one, an asymmetric coupler followed by a symmetric one and two asymmetric couplers. From the analysis of the device, we obtained the logic gates OR, XOR, AND, function 0, function A′·B and function A·B′, considering the OOK keying.

Obtaining optical logic gates – OR, XOR, AND and logic functions using asymmetric Mach-Zehnder interferometer based on photonic crystal fiber

A simple reconfigurable ultrahigh-speed optical device which can be configured to optical NOT, AND, or XOR logic operation via slight variations in the input signals applied to two identical parallel highly nonlinear fibers (HNLFs) is described. The cross-phase modulation (XPM) in the HNLF and phase shifter are used in the design to realize a reconfigurable all-optical logic gate operating at 120 Gb/s. The proposed reconfigurable ultrahigh-speed all-optical logic device could play a crucial role in the realization of future all-optical high-performance flexible optical networks.

The design of a reconfigurable all-optical logic device based on cross-phase modulation in a highly nonlinear fiber

We proposed a novel structure of ultrafast all optical Feynman logic gate based on the cross-phase modulation that is principle nonlinear effect in a quantum dot semiconductor optical amplifier assisted with a Mach-Zehnder interferometer at the wavelength of 1.55 µm. To realize ultrafast mechanism, an active layer with a thickness of 1.7-µm, and the confinement factor of 0.75 and 0.7 respectively for both TE0 and TM0 modes, are provided. By solving the rate equations, a gain difference up to 0.1 dB has been obtained. The proposed structure has the potential application in advanced optical devices such as optical memristors.

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Quantum-Dot Semiconductor Optical Amplifier: Performance and Application for Optical Logic Gates

The high speed and high volume of optical data are subjected to electronic conversions at the receiving end of the optical network for processing purposes. This optoelectronic conversion makes the system inefficient in terms of speed and bandwidth. When high-speed data are subjected to electronic processing, heat dissipates from electronic circuits. Another source of heat dissipation is the loss of information from the irreversible processors. The solution of this problem is reversible computing. This research paper proposes a novel 3 × 3 reversible XOR logic gate and XNOR logic gate in a single photonic circuit. The proposed photonic circuit works on the principles of cross-gain modulation and cross-phase modulation, which is introduced by the active regions of two semiconductor optical amplifier in a Mach–Zehnder interferometer structure. The proposed design works at 10 Gbps data rate. The average extinction ratio of the design is 18.58 dB, and the average quality factor is 63.03 dB. The optical cost of the proposed circuit is 1 unit.

A novel model of all-optical reversible XOR/XNOR logic gate on a single photonic circuit

In this work we performed a numerical study of optical logic gates based on a Sagnac interferometer, operating with short optical pulses (10 ps) in a PAM–ASK modulation scheme with binary amplitude modulation scheme. We examined the performance of a nonlinear Sagnac interferometer implementing two-input logical functions. We evaluated the effect resulting from an increment in the PAM coding parameter offset ( e ) , considering the anomalous group velocity dispersion (GVD) and nonlinear self phase modulation (SPM) in a lossless configuration. By analysing the transmitted output, we conclude it is possible to obtain logic gates OR for two different power-splitting ratios ρ of the coupler ( ρ = 0.1 and 0.2). After this step, we applied a dephasing control to the input pulses, aiming to achieve logic gates with ρ = 0.3 and ρ = 0.4 and to enhance the study of cases in which they had not been previously obtained. We obtained OR and AND logic gates with a phase variation study for ρ = 0.1 and 0.2. For ρ = 0.3 and 0.4, the variety and versatility of logic gates proved to be very broad where OR, AND and XOR gates were obtained.

PAM–ASK optical logic gates in an optical fiber Sagnac interferometer

In this work, we present a numerical study to investigate the transmission, extinction ratio, crosstalk and compression factor outputs of a Mach–Zehnder interferometer in photonic crystal fibers by varying the nonlinearity parameter of the fiber from β = 1 to β = 2 for three different nonlinearity profiles (constant, increasing and decreasing) and in three different scenarios (P0 = Pc, P0 Pc). We observed that the highest transmission (T = 67%), the highest extinction ratio (XR = 3.57 dB) and the lowest crosstalk (Xtalk = -5.25 dB) occurred in the third scenario (P0 = 110 kW > Pc) considering the decreasing profile for β = 1.35. Such condition enables applications such as TDMA and logic circuits.

Mach–Zehnder nonlinear interferometer in photonic crystal fibers with nonlinearity profiles

In this work, we studied the behavior of Sagnac interferometer powered by a CW signal and under the nonlinear effects of self-phase modulation, cross-phase modulation, and Raman, in two configurations (balanced and unbalanced) and five scenarios (by varying the value of the Raman fraction). In the balanced configuration, we observed that the presence of Raman effect in the loop changes the curves of transmissivity and reflectivity of the device, but only the components generated by the Raman effect (Stokes waves) are switched to the transmitted port. In the unbalanced configuration, we obtained an oscillating behavior as for transmissivity and reflectivity, which breaks the characteristic of nonlinear fiber mirror, thus enabling the transmission of the pumping wave for certain combinations of values of input power and Raman fraction.

F. T. C. B. Magalhães

Papers

PAM–ASK optical logic gates in an optical fiber Sagnac interferometer

Mach–Zehnder nonlinear interferometer in photonic crystal fibers with nonlinearity profiles

Unbalance of the Sagnac interferometer through nonlinear asymmetry