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We propose a coupled system of the Hirota equation and the Maxwell-Bloch equations to describe the wave propagation in an erbium doped nonlinear fiber with higher order dispersion.The Painleve property of the same is analyzed and the coupled system is found to be integrable. The Lax pair is also constructed and the single-soliton solution is explicitly shown. The coupled system is found to allow soliton-type propagation. PACS numbers: 42.SO.Rh, 02.30.Jr, 42.65. -k, 42.81.DpThe extraordinary growth of communication technology was made possible only because of the discovery of microwaves. Every day the amount of intelligence to be communicated becomes more and more, so communication using light wave technology has been developed. Optical communication gives the necessary bandwidth, which can handle numerous channels. Optical fibers made of silica are used for guiding the light waves.Still the entire efficiency of optical communication is not utilized. This is because of the undesired, natural problems of the fibers. The two major problems are the dispersion and the dissipation due to the frequency dependence of the index of refraction and the optical losses, respectively.The dispersion makes the optical pulse spread temporally so that the energy may fall on the next bit slot, so that cross talk or error detection may occur. The optical losses cause the vanishing of the pulse because of absorption and scattering. This also causes error detection.The other important natural phenomenon of optical fibers is the nonlinear effect. When the intensity of the optical pulses crosses a certain threshold value then the fiber behaves nonlinearly. The most important effect is self-phase modulation (SPM) due to Kerr nonlinearity.Kerr nonlinearity is defined as the intensity-dependent refractive index. SPM produces spectral broadening. The effect of SPM is in opposition to that of dispersion in the anomalous dispersion region (the wavelength at which the blueshifted frequency component travels faster than the redshifted frequency).So with the proper selection of the parametric conditions, the effect of dispersion can be exactly balanced with the help of SPM. With this principle the pulse will travel through a very long distance without any change in shape -this effect is called the soliton [1,2].In 1980, Mollenauer, Stolen, and Gordon [3] observed experimental solitons for the first time in low-loss fibers.Later in 1986 [4], the same group reported that the experimentally observed solitons did not have the same properties as theoretical ones. This is. because of higher order effects like higher order dispersion, self-steepening, and stimulated inelastic scattering. All these effects will give some additional perturbation to the soliton system.It is evident that if one analyzes any type of soliton in fibers, all the above important additional effects have to be included. Here in this Letter we mainly concentrate on this problem of our proposed system.The other important nonlinear effect is the coherent interaction of the optical fi...

The survey focuses on the most significant contributions in the field of fiber optic plasmonic sensors (FOPS) in recent years. FOPSs are plasmonic sensor-based fiber optic probes that use an optical field to measure the biological agents. Owing to their high sensitivity, high resolution, and low cost, FOPS turn out to be potential alternatives to conventional biological fiber optic sensors. FOPS use optical transduction mechanisms to enhance sensitivity and resolution. The optical transduction mechanisms of FOPS with different geometrical structures and the photonic properties of the geometries are discussed in detail. The studies of optical properties with a combination of suitable materials for testing the biosamples allow for diagnosing diseases in the medical field.

We consider the evolution of nonlinear optical pulses in cubic-quintic nonlinear media wherein the pulse propagation is governed by the generalized nonlinear Schrödinger equation with exponentially varying dispersion, cubic, and quintic nonlinearities and gain and/or loss. Using a self-similar analysis, we find the chirped bright soliton solutions in the anomalous and normal dispersion regimes. From a stability analysis, we show that the soliton in the anomalous dispersion regime is stable, whereas the soliton in the normal dispersion regime is unstable. Numerical simulation results show that competing cubic-quintic nonlinearities stabilize the chirped soliton pulse propagation against perturbations in the initial soliton pulse parameters. We characterize the quality of the compressed pulse by determining the pedestal energy generated and compression factor when the initial pulse is perturbed from the soliton solutions. Finally, we study the possibility of rapid compression of Townes solitons by the collapse phenomenon and the exponentially decreasing dispersion. We find that the collapse could be postponed if the dispersion increases exponentially.

Abstract-Systems with colocated sensor-actuator pairs exhibit the interesting property of pole-zero interlacing. Integral resonance control (IRC) exploits this property by changing the polezero interlacing to zero-pole interlacing. The unique phase response of this class of systems enables a simple integral feedback controller to add substantial damping. Over the past few years, IRC has proven to be extremely versatile and has been applied to a wide variety of systems whose dominating dynamics of interest can be accurately modeled by second-order transfer functions. To date, a manual approach has been employed to determine the parameters of the IRC scheme, namely the feed-through term and the integral gain. In this paper, the relationship between the feed-through term, integral gain, and achievable damping is derived analytically for undamped/lightly damped second-order systems. The relationship between damping controller and an outer servo loop is also derived. These results add to the current understanding of colocated systems and automate the design of IRC controllers with a specified damping and tracking bandwidth. The presented results are applied to design and implement a damping and tracking controller for a piezoelectric nanopositioning stage.

We propose a six-fold photonic quasi-crystal fibre with a trapezoidal analyte channel based on surface plasmon resonance for the detection of high refractive index liquid analytes and numerically analyse its sensing performance for different liquid analyte refractive indices and heights using the finite element method. In contrast to the common D-shaped structure photonic crystal fibre, we design a trapezoidal analyte channel to investigate the role of the sample liquid height within the channel and discussed the feasibility of the fabrication process. We find that with various liquid analyte heights ratio of 20%, 25%, 30% and 50% of the maximum channel height, the proposed biosensor exhibits linear sensing performance with a maximum refractive index (RI) sensitivity of 4400 nm/RIU, 6100 nm/RIU, 8000 nm/RIU and 17000 nm/RIU respectively, for analytes RI range of 1.44 to 1.57, 1.41 to 1.51, 1.40 to 1.49 and 1.40 to 1.44. This sensor is suitable to detect various high RI chemicals, biochemicals and organic chemical samples. Owing to its simple structure of the proposed biosensor with promising linear sensing performance, we envisage that this biosensor could turn out to be a versatile and competitive instrument for the detection of high refractive index liquid analytes.

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