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.

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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.

We report a graphene-based indium tin oxide coated surface plasmon resonance sensor built on a D-shaped optical fiber for near infrared. Different parameters of the proposed sensor have been optimized to obtain a maximal phase matching between the core guided mode and the plasmon mode using finite element method. Wavelength sensitivity of the proposed structure is as high as 5700 nm/RIU with a maximum resolution of 1.754 × 10 −5 RIU. The proposed sensor can also be used for bio layer thickness monitoring with a maximum resolution of 62.5 pm in wavelength interrogation.

We demonstrate almost chirp-and pedestal-free optical pulse compression in a nonlinear fiber Bragg grating with exponentially decreasing dispersion. The exponential dispersion profile can be well-approximated by a few gratings with different constant dispersions. The required number of sections is proportional to the compression ratio, but inversely proportional to the initial chirp value. We propose a compact pulse compression scheme, which consists of a linear and nonlinear grating, to effectively compress both hyperbolic secant and Gaussian shaped pulses. Nearly transform-limited pulses with a negligibly small pedestal can be achieved.

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