TOAD or Tera Hertz Optical Asymmetric Demultiplexer is an optical switch. Using this switch, we have invented an optical comparator. This optical comparator circuit is very simple in structure with a higher speed (200 Gbps) and finds useful application in optical computation and communication network system. We have simulated all three outputs in detail and shown the eye diagram of all three outputs of the optical comparator. We found high values of extinction ratio (ER), contrast ratio (CR), and quality factor (Q value) for the three outputs of the comparator.

In this paper, we theoretically analyze optically-induced transparency and absorption properties of a weak probe field in a two-mode coupled micro-cavity system and explore the tunable asymmetric Fano line shape of the transmission rates of the probe field. Both the modes in our system consist of an optical Kerr medium, one of them being passive while the other mode can be either active or passive. The forward transmission and backward reflection profile of the probe field are investigated for both passive–passive and passive–active cavity systems by varying different system parameters such as probe field detuning, photon tunneling strength, gain-to-loss ratio, etc. The results of this study have the potential to be applied in construction of quantum telecommunication and photonic devices.

In this work, the role of asymmetry in the beam profile of finite Airy-Gaussian (AiG) laser is presented to explore its propagation dynamics in collisionless magnetized plasma. Emphasis is on analyzing the self-trapping condition for both extraordinary (E) and ordinary (O) modes of propagation of AiG laser beam. Theoretical formulation is based on obtaining nonlinear coupled differential equations for beam-width parameters in both transverse dimensions of the beam with the help of parabolic equation approach under WKB and paraxial approximations. It is found that asymmetry in the modulation parameters significantly affects self-focusing of finite AiG beam. Moreover, the same initial intensity parameter for simultaneous self-trapping of both modes of propagation is noteworthy.

Direct growth of large-area uniform graphene films on insulating materials could facilitate the applications of graphene in optoelectronic devices. The ultrafast photocarrier relaxation and saturable absorption of direct chemical vapor deposition-grown graphene glasses, with lots of defects, are studied by using femtosecond time-resolved pump–probe and Z-scan techniques at 800nm. We find that both the relaxation times associated with hot carrier cooling and the hot phonon effect are greatly suppressed in these defect-rich graphene glasses, which further leads to the increase of both saturation intensity and anisotropy in transient optical response for graphene glasses as compared with defect-free graphene. And, both the suppression effect and saturation intensity increase with the thickness of graphene film. The dominance of defect-assisted carrier-acoustic phonon scattering (i.e., supercollision, the collision of a carrier with both an acoustic phonon and defects) in the cooling process of hot carriers is responsible for the suppression of relaxation time.

In the this study, we focus on the growth of a metal-organic creatininium borate (CRB) single crystal for third-order nonlinear optical (NLO) applications. Optically transparent & wide optical band gap single crystals of CRB were successfully harvested by adopting a slow evaporation solution technique (SEST) at a constant 40∘C temperature. The structural identification and lattice parameters of the grown sample were determined by powder X-ray diffraction (PXRD) using Rietveld analysis by FullProf Suite software. The occurrence of vacancy/interstitial defects produced during growth was investigated by high-resolution X-ray diffraction (HRXRD) using omega scan arrangement. A single peak with lower full width half maxima (56.4 arc s) was obtained from the scan which suggests that there were no grain boundaries for the grown crystal. Surface morphology and its features such as concentration of dislocations and defect sites on the as-grown sample were scrutinized using the etching technique. The optical band gap and UV–vis cut-off were examined and found to be 5.39 eV and 230 nm, respectively. Photoluminescence characteristics of the crystal show an emission at 377 nm upon excitation with a wavelength of 336 nm. The presence of radiative and non-radiative transitions inside the crystal due to excitation upon 266 nm laser was identified using time-resolved photoluminescence. Thermal stability and decomposition temperature of the compound were obtained by thermo-gravimetric analysis (TGA) and differential scanning calorimetry (DSC). The third-order nonlinearity of the crystal was determined by Z-scan measurement technique with a femtosecond Ti-sapphire laser.

In this paper, the optical soliton and solitary wave solutions of the (2+1)-dimensional Mel’nikov equation are investigated using the Kudryashov R function technique. The Kudryashov R function approach has various features that significantly facilitate symbolic computing, particularly for highly dispersive nonlinear equations. In computations, this approach has the benefit of not requiring the use of a certain function form. This approach gives an algorithm that is straightforward, efficient, and simple for finding solitary wave solutions. In addition, this approach is very influential and reliable when it comes to discovering hyperbolic function solutions of nonlinear equations. Many new hyperbolic function solutions have been obtained from the governing equation by using this technique. In addition, numerous types of soliton solutions describing various structures of optical solitons are retrieved. Using this method, breather, W-shaped, bell shaped, and bright soliton solutions have been generated from the governing equation. From the obtained results, it can be asserted that the applied approach may be a useful tool for addressing more highly nonlinear problems in various fields. By choosing particular values for the relevant parameters, the dynamic features of some breather, W-shaped, bell shaped and bright soliton solutions to the (2+1)-dimensional Mel’nikov equation have been displayed in 3D, 2D and contour graphs.

In this paper, we study the Radhakrishnan–Kundu–Lakshmanan equation (RKLE) that plays a key role in modeling the nonlinear propagation of the light pulses. Two novel methods namely Wang’s Bäcklund transformation-based method and Wang’s direct mapping method are employed to construct the diverse exact optical soliton solutions. Abundant exact solutions like the bright soliton solution, dark soliton solutions, singular soliton solutions, algebraic solitary wave solutions and the singular periodic wave solutions expressed in the form of the rational function type, double-exp function type, Sin-Cos function type, Tan function type, Cot function type, Sinh-Cosh function type, Tanh function type, Coth function type, Sech function type, Csch function type, Sec function type and Csc function type are obtained. The dynamics of the different exact solutions are presented through the 3D plot, contour and 2D curve, and the corresponding physical interpretations are elaborated in detail. It is confirmed that the proposed methods are effective and powerful, and can be adopted to construct the optical solitons of the other PDEs arising in the optical physics.

A novel plasmonic waveguide structure consisting of a rectangular resonator side coupled with a split ring resonator (SRR) and a metal–insulator–metal (MIM) waveguide with metal baffle was proposed. The transmission characteristics of the present structure were simulated by a finite-difference time-domain (FDTD) method. The results show that the structure can realize three typical plasmonically-induced reflection (PIR) windows. Meantime, the PIR window can be tuned vertically and horizontally, respectively, and multiple PIR windows with different wavelength intervals can also be obtained by changing the split position. In addition, the sensitivity of the proposed structure can reach up to 1,075nm/RIU. Furthermore, a rectangular resonator was added to the other side of the plasmonic waveguide structure for realizing the dual-channel PIR window. Another SRR was added to form a symmetrical structure, which further improved the sensitivity and transmittance. Undoubtedly, the proposed structure will have potential applications in sensor and optical switches.

FTIR, FT-Raman and NMR are studied to explore the functional groups, the vibration modes and its coupling interactions for the grown single crystal piperazine-1,4-diium bis (4-aminobenzenesulfonate) (PABS). The cut-off wavelength at 303 nm of UV–Visible spectrum exhibits great transmittance over the entire visible spectrum. Photoluminescence spectral study revealed the electron excitation notably in blue emission range. The range of susceptibility and nonlinear refractive index was obtained from second and third harmonic generations of PABS crystals. At various temperatures, the thermal stability of the crystal and the crystal dielectric characteristics had been studied in relation to frequency. The hardness of the crystal was obtained by microhardness measurements.

Wavelength division multiplexing (WDM) is one of the emerging technologies for data transmission in 5G access network assembly between the antenna unit (AU) and the distribution unit (DU). Here, in this work, we evaluate and analyze a dense wavelength division multiplexing (DWDM) — passive optical networks (PONs) employing erbium–ytterbium-doped fiber amplifier (EYDFA) + Raman hybrid optical amplifier (HOA) using two modulation schemes — modified duobinary return to zero (MDRZ) and differential phase shift keying (DPSK) for alternate channels, where the channel count has been varied from 8 to 40. The system has been analyzed over the wavelength span of 1550–1558.8nm with a channel spacing, input power and data rate of 25GHz, 0dB and 40Gb/s, respectively. An average gain, gain ripple and optical signal-to-noise ratio (OSNR) of 20.87, 0.95 and 30dB, respectively have been observed in the case of HOA along with the achievement of Q-factor of up to 9 at the receiving end of the system. The DPSK-modulated channels result in higher values of gain and OSNR along with lower gain ripple as compared to MDRZ channels making the proposed system a good option for 5G access network applications.

In this work, a flat-top and broadband supercontinuum (SC) generation in photonic crystal fibers (PCFs) infiltrated with carbon tetrachloride (CCl4) with different air hole diameters in the cladding has been introduced. The optical properties of the fundamental mode are analyzed by numerical simulation. Based on the obtained results, two optimized PCFs with small dispersion are proposed and verified against SC generation in detail. The first fiber has an all-normal dispersion of −9.376ps.nm−1.km−1 at the pump wavelength of 0.98μm, generating broadband of 768nm and flat-top with only 0.3nJ of input energy and time duration of 90fs. In the meantime the dispersion property of the second fiber is anomalous, which equals 1.105ps⋅nm−1⋅km−1 at 1.3μm pump wavelength. The second fiber generates a SC spectrum of 1,751.1nm with input energy and time duration of 0.55nJ and 55fs, respectively. Proposed fibers are suitable for all-fiber SC sources which could lead to new low-cost all-fiber optical systems.

Single crystals of zinc sulfate doped L-alanine (LAZ) were grown by adopting the slow evaporation technique at room temperature. The crystal structure of LAZ was determined using single-crystal X-ray diffraction. The functional groups of LAZ were identified by FT-IR spectroscopy analysis. UV–Visible–NIR transmittance study was carried out, and the bandgap energy was found. A fluorescence study was performed to get the emission spectrum of the LAZ crystal. The Vickers microhardness test is used to determine the LAZ crystals mechanical behavior. Thermogravimetric and differential thermal analyses have also been studied to investigate the thermal property of the LAZ crystal. The efficiency of the title crystal’s second harmonic generation (SHG) was investigated. The electrical properties were estimated by impedance study.

In this paper, the extended simplest equation method is utilized to construct the novel exact optical solitons solutions of the perturbed time fractional Chen–Lee–Liu equation with conformable fractional derivative. The acquired optical solitons and other solutions are expressed via the rational functions, the trigonometric functions, and the hyperbolic functions; in addition to guaranteeing the existence of the acquired results, the constrain conditions are provided. Furthermore, to elucidate the magnitude of the proposed equation, various obtained solutions are plotted via two-dimensional (2D) and three-dimensional (3D) graphs using appropriate values of parameters. It is observed that the present technique is a powerful tool and efficient for finding the analytical solution for nonlinear differential equations of integer and fractional orders.

We investigate theoretically an optomechanical system composed of an optical mode and a mechanical mode interacting through first-order coupling and second-order coupling in the presence of a Kerr nonlinear medium. We study how the nonlinearities (second-order optomechanical coupling and Kerr nonlinearity) alter the optical output spectrum, optical quadrature squeezing and optomechanical entanglement. It is shown that the intensity of the output optical spectrum decreases drastically with an increase in second-order optomechanical coupling while it increases significantly with an increase in Kerr nonlinear parameter. More interestingly, by choosing suitable second-order optomechanical coupling and detuning of the optical cavity field, one can achieve strong squeezing of the cavity light field. Further, these nonlinearities play an important role in creating robust optomechanical entanglement between optical and mechanical modes. Hence, the presence of various nonlinearities in the system can be a good platform for achieving the squeezing of light and robust optomechanical entanglement which can be used in realizing better quantum optomechanical devices.

Nematicons became a key topic of interest in liquid crystal technology in recent years. This paper contributes in understanding the fantastic features of nematicons in optics and further disciplines. This piece of research investigates nematicons for obtaining various exact solutions for Kerr and non-Kerr law nonlinearities with the help of the Kudryashov’s approach and the tanh–coth technique. The acquired outcomes involve rational, periodic and hyperbolic solutions as well as their combo-type solutions for all the four cases of nonlinearity. A comparative study is conducted to show the novelty of present results with results already existing in the literature. The constraint conditions obtained ensured that the existence of these solutions is extraordinarily favorable to further investigate the dynamics of nematicons for various kinds of nonlinearity. The dynamics of the few of the obtained solutions are also discussed by 3D plots.

We have numerically generated the rogue waves supported by discrete nonlinear Schrödinger equation (DNLSE). The investigation has been made on pure cubic DNLSE as well as on cubic-quintic discrete nonlinear Schrödinger equation (CQDNLSE). Runge–Kutta fourth (RK4) order method has been employed to obtain these results. For the cubic DNLSE breathers are found to be localized in one of the dimensions and periodic in the other dimensions, whereas rogue waves are found to be appearing from nowhere and disappearing without a trace. For CQDNLSE it is reported that the sign of quintic term possesses a significant effect on the intensity of the rogue waves. Further these waves are appearing from nowhere but instead of disappearing these show periodic reappearance. For larger value of quintic coefficient this phenomenon is visible at shorter length scale. Breathers are reported for the first time for the cubic DNLSE. The obtained results for CQDNLSE are unobserved previously in any constant coefficient discrete nonlinear equation.

In the all-optical domain, the reflective semiconductor optical amplifier (RSOA) creates due attention in the research community because the RSOA has high gain, low-power consumption, high-speed signal processing ability as well as low noise performance. In this work, we have proposed dibit-based OR and NOR gates using RSOA. Dibit-based logic is utilized in this design to get the reduced bit-error problems and high degree of parallelism. To verify the functionality of the aforementioned designs, we have used MATLAB software and also the quality factor (Q), extinction ratio (ER), contrast ratio (CR), and bit-error-rate (BER) have been calculated.

In recent trends, digital systems in the light of power dissipation are a crucial issue. In computing, the computational process of reversible logic is bijective and can decrease the rising issue of power dissipation. In reversible circuit design, Peres gate considered as one of the fundamental reversible gate. Therefore, a Peres gate using Add/Drop Multiplexer (ADM) and Reflective Semiconductor Optical Amplifier (RSOA) is proposed in this paper. Frequency encoding scheme and dibit-based logic are incorporated here. In long range transmission, frequency encoding bears huge benefits in respect with the other encoding techniques. This encoding technique may decrease the probability of bit error. Due to the high gain and low noise property of RSOA, the proposed design can perform operations like computation, data processing, etc. at ultra-high speed with low noise. MATLAB Simulink (R2018a) software has been used to verify the operation of the proposed design.

MAPbBr3 quantum dots in SiO2 mesopores (∼4.4nm) were prepared by the spin-coating method, and their luminescence and nonlinear optical properties were studied by time-resolved photoluminescence (TRPL) and Z-scan techniques. The results showed that the absorption and photoluminescence peaks are at 464nm and 476nm, respectively. The TRPL spectroscopy showed two relaxation processes, a short lifetime (1.04ns) and a long lifetime (4.49ns), attributed to the trap–capture recombination and the electron–hole radiative recombination, respectively. Two-photon absorption (TPA) coefficient was 529cm/GW at 800nm. The nonlinear signal changed from TPA to saturable absorption with increase in light intensity.

The slow evaporation solution growth technique (SEST) was used to successfully grow inorganic single crystals of sodium sulphamate (NaS) in ambient conditions. The titled crystal’s structural and optical characteristics were evaluated using a variety of spectroscopic techniques. Powder X-ray diffraction (PXRD) analysis and Fourier transform infrared (FT-IR) spectroscopy were used to examine the crystal structure characteristics. Using UV-Vis spectroscopy, the optical properties of the NaS crystal were carefully examined, and the optical bandgap was determined using Tauc’s plot. The HR-XRD analysis examined crystalline perfection. Additionally, photoluminescence spectroscopy determined the emission spectra, and time-resolved photoluminescence measured the decay rate. The Z-scan technique was also used to examine the titled crystal’s nonlinear optical (NLO) performance.