2D Nonlinear Photonic Crystal Research Articles

Performance evaluation of all-optical NOT, XOR, NOR, and XNOR logic gates based on 2D nonlinear resonant cavity photonic crystals

Performance evaluation of all-optical NOT, XOR, NOR, and XNOR logic gates based on 2D nonlinear resonant cavity photonic crystals

Hot-spots and gain enhancement in a doubly pumped parametric down-conversion process.

We experimentally investigate the parametric down-conversion process in a nonlinear bulk crystal, driven by two non-collinear pump modes. The experiment shows the emergence of bright hot-spots in modes shared by the two pumps, similar to the phenomenology recently observed in 2D nonlinear photonic crystals. By exploiting the spatial walk-off between the two extraordinary pump modes, we have been able to recreate a peculiar resonance condition, reported by a local enhancement of the parametric gain, which corresponds to a transition from a three-mode to a four-mode coupling. From a quantum point of view, this opens the way to the generation of multimode entangled states of light, such as tripartite or quadripartite states, in simple bulk nonlinear sources.

Simulating Correlations of Structured Spontaneously Down‐Converted Photon Pairs

AbstractIntroducing structure into photon pair generation via spontaneous parametric down‐conversion (SPDC) is shown to be useful for controlling the output state and exploiting new degrees of freedom for quantum technologies. This paper presents a new method for simulating first‐ and second‐order correlations of the down‐converted photons in the presence of structured pump beams and shaped nonlinear photonic crystals. This method is nonperturbative, and thus accounts for high‐order effects, and can be made very efficient using parallel computing. Experimental results of photodetection and coincidence rates in complex spatial configurations are recovered quantitatively by this method. These include SPDC in 2D nonlinear photonic crystals, as well as with structured light beams such as Laguerre Gaussian and Hermite Gaussian beams. This simulation method reveals conservation rules for the down‐converted signal and idler beams that depend on the nonlinear crystal modulation pattern and the pump shape. This scheme can facilitate the design of nonlinear crystals and pumping conditions for generating non‐classical light with pre‐defined properties.

All optical NOR and NAND gates using four circular cavities created in 2D nonlinear photonic crystal

The paper presents novel 2D photonic crystal (PhC) structures comprising of four circular cavities (CCs) that mimic NOR and NAND gates. 2D Finite difference time domain (2DFDTD) method is used for simulation and analysis of optical behavior of the proposed structures considering perfectly matched layers (PML) around the simulation region. Photonic band gap (PBG) and projected band diagram are obtained using plane wave expansion (PWE) method. It is shown that both the structures function with optical inputs of same wavelength and intensity. The proposed NOR and NAND gates are having low operating powers and good contrast ratio. Being universal gates, NOR and NAND allows for Boolean completeness.Implementation of bypass waveguides is a unique feature of the structures proposed in this paper. When the output is LOW, most of the optical power channelizes out of the structure through bypass waveguides, which otherwise, would go into the input ports affecting the input devices or would remain trapped inside the structure resulting in heating. This issue is not touched in the previous literature and in our opinion, being addressed for the first time.

Ultra-fast and compact all-optical encoder based on photonic crystal nano-resonator without using nonlinear materials

In this paper an ultra-compact all-optical encoder is presented by using a two-dimensional photonic crystal. The designed logic gate is based on the interference effect. The proposed structure consists of several photonic crystal waveguides connected by 2 nano-resonators. The nano-resonators are designed to reduce the size of the radius of the dielectric rods. The contrast ratios and delay time for the proposed all-optical encoder are respectively 6 dB and 125 fs. The size of the structure is equal to 132 µm2. Equality of the output power in the logic states “one”, the small dimensions, the low delay time, compact and simple structure have shown that the logic gate is suitable for the using in optical integrated circuits. Full Text: PDF ReferencesA. Salmanpour, Sh. Mohammadnejad, A. Bahrami, "Photonic crystal logic gates: an overview", Optical and Quantum Electronics. 47, 2249 (2015). CrossRef S. C. Xavier, B. E. Carolin, A. p. Kabilan, W. Johnson, "Compact photonic crystal integrated circuit for all-optical logic operation", IET Optoelectronics. 10, 142 (2016). CrossRef Y. Miyoshi, K. Ikeda, H. Tobioka, T. Inoue, S. Namiki, K. Kitayama, "Ultrafast all-optical logic gate using a nonlinear optical loop mirror based multi-periodic transfer function", Optics Express. 16, 2570 (2008). CrossRef D. K. Gayen, A. Bhattachryya, T. Chattopadhyay, J. N. Roy, "Ultrafast All-Optical Half Adder Using Quantum-Dot Semiconductor Optical Amplifier-Based Mach-Zehnder Interferometer", Journal of Lightwave Technology. 30, 3387 (2012). CrossRef A. Mohebzadeh-Bahabady, S. Olyaee, "All-optical NOT and XOR logic gates using photonic crystal nano-resonator and based on an interference effect", IET Optoelectronics. 12, 191 (2018). CrossRef Z. Mohebbi, N. Nozhat, F. Emami, "High contrast all-optical logic gates based on 2D nonlinear photonic crystal", Optics Communications. 355, 130 (2015). CrossRef M. Mansouri-Birjandi, M. Ghadrdan, "Full-optical tunable add/drop filter based on nonlinear photonic crystal ring resonators", Photonics and Nanostructures-Fundamentals and Applications. 21, 44 (2016). CrossRef H. Alipour-Banaei, S. Serajmohammadi, F. Mehdizadeh, "Effect of scattering rods in the frequency response of photonic crystal demultiplexers", Journal of Optoelectronics and Advanced Materials. 17, 259 (2015). DirectLink A. Mohebzadeh-Bahabady, S. Olyaee, H. Arman, "Optical Biochemical Sensor Using Photonic Crystal Nano-ring Resonators for the Detection of Protein Concentration", Current Nanoscience. 13, 421 (2017). CrossRef S. Olyaee, A. Mohebzadeh-Bahabady, "Designing a novel photonic crystal nano-ring resonator for biosensor application", Optical and Quantum Electronics. 47, 1881 (2015). CrossRef F. Parandin, R. Malmir, M. Naseri, A. Zahedi, "Reconfigurable all-optical NOT, XOR, and NOR logic gates based on two dimensional photonic crystals", Superlattices and Microstructures. 113, 737 (2018). CrossRef F. Mehdizadeh, M. Soroosh, H. Alipour-Banaei, "Proposal for 4-to-2 optical encoder based on photonic crystals", IET Optoelectronics. 11, 29 (2017). CrossRef M. Hassangholizadeh-Kashtiban, R. Sabbaghi-Nadooshan, H. Alipour-Banaei, "A novel all optical reversible 4 × 2 encoder based on photonic crystals", Optik. 126, 2368 (2015). CrossRef T. A. Moniem, "All-optical digital 4 × 2 encoder based on 2D photonic crystal ring resonators", Journal of Modern Optics. 63, 735 (2016). CrossRef S. Gholamnejad, M. Zavvari, "Design and analysis of all-optical 4–2 binary encoder based on photonic crystal", Optical and Quantum Electronics. 49, 302 (2017). CrossRef H. Seif-Dargahi, "Ultra-fast all-optical encoder using photonic crystal-based ring resonators", Photonic Network Communications. 36, 272 (2018). CrossRef S. Olyaee, M. Seifouri, A. Mohebzadeh-Bahabady, and M. Sardari, "Realization of all-optical NOT and XOR logic gates based on interference effect with high contrast ratio and ultra-compacted size", Optical and Quantum Electronics. 50, 12 (2018). CrossRef C. J. Wu, C. P. Liu, Z. Ouyang, "Compact and low-power optical logic NOT gate based on photonic crystal waveguides without optical amplifiers and nonlinear materials", Applied Optics.51, 680 (2012). CrossRef Y. C. Jiang, S. B. Liu, H. F. Zhang, X. K. Kong. "Realization of all optical half-adder based on self-collimated beams by two-dimensional photonic crystals", Optics Communications. 348, 90 (2015). CrossRef A. Salmanpour, S. Mohammadnejad, P. T. Omran, "All-optical photonic crystal NOT and OR logic gates using nonlinear Kerr effect and ring resonators", Optical and Quantum Electronics. 47, 3689 (2015). CrossRef E. H. Shaik, N. Rangaswamy, "Single photonic crystal structure for realization of NAND and NOR logic functions by cascading basic gates", Journal of Computational Electronics. 17, 337 (2018). CrossRef

All-optical simultaneous AND & XOR logic gates based on nonlinear micro-ring resonator

ABSTRACTIn this paper, we have proposed AND and XOR logic gates simultaneously in one structure. The presented structure is based on two-dimensional (2D) nonlinear photonic crystal with T–shaped waveguide and micro-ring resonator. In the proposed structure, the power consumption is that is lower than similar logic gates and the extinction ratio is about 6.5 dB. Also, the switching time is attained to be 0.2 and 0.26 ps for AND and XOR logic gates, respectively. Simplicity and small size (18.4 µm×18.4 µm) of the structure make it suitable for photonic integrated circuits (PICs). All simulations are based on finite-difference time-domain (FDTD) and plane wave expansion (PWE) numerical methods.

Golden Ratio Gain Enhancement in Coherently Coupled Parametric Processes

Nonlinear optical processes are an essential tool in modern optics, with a broad spectrum of applications, including signal processing, frequency conversion, spectroscopy and quantum optics. Ordinary parametric devices nevertheless still suffer from relatively low gains and wide spectral emission. Here we demonstrate a unique configuration for phase-matching multiple nonlinear processes in a monolithic 2D nonlinear photonic crystal, resulting in the coherent parametric emission of four signal and idler modes, featuring an exponential gain enhancement equal to the Golden Ratio. The results indicate a new route towards compact high-brightness and coherent sources for multi-photon generation, manipulation and entanglement, overcoming limitations of conventional parametric devices.

Multiple generations of high-order orbital angular momentum modes through cascaded third-harmonic generation in a 2D nonlinear photonic crystal.

We experimentally demonstrate multiple generations of high-order orbital angular momentum (OAM) modes through third-harmonic generation in a 2D nonlinear photonic crystal. Such third-harmonic generation process is achieved by cascading second-harmonic generation and sum-frequency generation using the non-collinear quasi-phase-matching technique. This technique allows multiple OAM modes with different colors to be simultaneously generated. Moreover, the OAM conservation law guarantees that the topological charge is tripled in the cascaded third-harmonic generation process. Our method is effective for obtaining multiple high-order OAM modes for optical imaging, manipulation, and communications.

Effect of field modulation on the quasi-phase-matching for second harmonic generation in a two-dimensional nonlinear photonic crystal

Second harmonic generation (SHG) in a two-dimensional (2D) nonlinear photonic crystal (NPC) with finite width along [Formula: see text]-direction that is embedded in air is investigated, without adopting the traditional approximations such as a plane-wave approximation (PWA) and slowly varying amplitude approximation (SVAA). The so-called quasi-phase-matching (QPM) and the corresponding SHG conversion efficiency can be modulated significantly by the field of fundamental wave (FW). It is assumed that the incident light, along [Formula: see text]-direction, is normally launched upon the surface of the sample, and QPM for different directions is investigated. It is found that the QPM shows significant differences, compared with the traditional QPM along the two different directions: in the direction of finite width of the sample, the peak value of SHG conversion efficiency is deviated from the traditional case and it gets to its peak values when the transmittance resonance occurs. However, in the other direction, the deviation from the traditional QPM arises from the field modulation of the second harmonic wave (SHW) and in this direction, it is investigated that the full width at half maximum of QPM is much wider than that in the direction of finite width of the sample. These results can be used to provide a theoretical guidance for achieving QPM SHG.

On the theory of second-harmonic generation in 2D nonlinear photonic crystals with arbitrary domain structures

Theoretical analysis is given to second-harmonic generation in 2D nonlinear photonic crystals of rectangular symmetry with rectangular domains. Formulas for the nonlinear response of the crystal with an arbitrary domain structure are derived within the approximation of a given field. A possibility of calculating time profiles of second-harmonic pulses down to the femtosecond range is demonstrated.

On theory of second harmonic generation in 2D nonlinear photonic crystals with arbitrary structures

On theory of second harmonic generation in 2D nonlinear photonic crystals with arbitrary structures

Nonlinear Raman-Nath diffraction of femtosecond laser pulses in a 2D nonlinear photonic crystal.

We study second-harmonic generation (SHG) of femtosecond laser pulses in a rectangular two-dimensional nonlinear photonic crystal (NLPC). Multiple SH beams were observed in the vicinity of the propagation direction of the fundamental beam. It has been verified that the angular positions of these beams obey the conditions of nonlinear Raman-Nath diffraction (NRND). The measured SH spectra of specific NRND orders consist of narrow peaks that experience a high-frequency spectral shift as the order grows. We derive an analytical expression for the process studied and find the theoretical results to be in good agreement with the experimental data. We estimate the enhancement factor of nonlinear Raman-Nath diffraction in 2D NLPC to be 70.

High contrast all-optical logic gates based on 2D nonlinear photonic crystal

We have proposed the all optical XOR, XNOR, NAND and NOT logic gates based on two-dimensional (2D) photonic crystals (PCs). In all structures the nonlinear Kerr effect has been used. The gates function is based on the destructive interference of the input signals. The phase difference between the input signals has been caused by the different signal travelling paths. To demonstrate the performance of the XNOR, NOT, and NAND gates a control port has been added to the structure. The gates have been operated at the frequency of 0.341(c/a) where ‘a’ and ‘c’ are the lattice constant and the speed of light in vacuum, respectively. Due to the maximum required input power of P0=277(mW/μm2) for the XOR, NOT, and XNOR gates and P0=554(mW/μm2) for the NAND gates, and the high contrast ratio of at least 20dB between the ON and OFF states, these logic gates are applicable for real time communications. Simulations are based on the finite-difference time-domain (FDTD) numerical method.

Multi-resonant optical parametric oscillator based on 2D-PPLT nonlinear photonic crystal

The aim of this work is to achieve an optical parametric oscillator based on two-dimensional periodically poled lithium tantalate (2D-PPLT) crystals that are designed to allow multiple reciprocal lattice-vector contribution to the quasi-phase matching scheme. We are particularly interested in the effect of the multi-wavelength parametric generation performed by the 2D nonlinear photonic crystal to achieve a multi-resonant optical parametric oscillator. The performances are studied in terms of generation efficiency and multi-wavelength generation.

Comparison of asymptotic and transfer matrix approaches for evaluating intensity-dependent dispersion in nonlinear photonic and phononic crystals

This paper analyzes intensity dependent dispersion of acoustic and electromagnetic waves in nonlinear one-dimensional (1D) periodic media. Media considered include layered 1D crystals characterized by constitutive laws with cubic strain nonlinearities (phononic), and by cubic time-dependent Kerr nonlinearities (photonic). A recently presented perturbation approach is generalized such that it can be successfully applied to the analysis of wave propagation in weakly nonlinear elastic and electromagnetic systems. In both, the analysis predicts amplitude-dependent dispersion leading to tunable bandgaps. These predictions are compared with those obtained from a simplified analysis conducted by linearizing the governing equations about an assigned field intensity followed by application of the transfer matrix method, as is commonly done in nonlinear photonic crystal studies. Comparison of the two methods generally shows good dispersion agreement; however, in phononic systems the transfer matrix analysis does not accurately capture high-strain behavior that occurs for some configurations, such as those with thin nonlinear layers, and may even predict erroneous bandgaps. Numerical predictions resulting from a finite-element analysis of the nonlinear media confirm the improved accuracy of the perturbation approach, suggesting its continued use for predicting intensity-dependent dispersion in 2D and 3D nonlinear phononic and photonic crystals.

Internal Q-switching and self-optical parametric oscillation in a two-dimensional periodically poled Nd:MgO:LiNbO_3 laser

We report on an internally Q-switched self-optical parametric oscillator (SOPO) based on a monolithic two-dimensional (2D) periodically poled Nd:MgO:LiNbO(3) (Nd:MgO:PPLN) integrating three device functionalities of a laser gain medium, an electro-optic Bragg Q-switch, and an optical parametric gain medium (OPGM). The quasi-phase-matching conditions required by the Bragg Q-switch and OPGM are both satisfied in the 2D nonlinear photonic crystal (NPC) structure formed in the Nd:MgO:PPLN. A 1525 nm signal with a pulse energy of ∼3.3 μJ (>350 W peak power) was obtained from the SOPO at 8.5 W diode pump power. An off-angle signal at 1612 nm, amplified by a unique gain-enhancement effect in this 2D NPC, was also observed. Tuning of the SOPO in the eye-safe region was demonstrated.

Computer simulation and observation of anomalous light emission from nonlinear photonic crystal with various geometry of its elements

Recently, in papers [1, 2] were described the effect of long-time emission of photonic crystal (synthetic opals) under the action of nanosecond laser pulse. The duration of the luminescence is of the order of seconds. Despite on the other phenomena, which were considered in these papers, below we focus our attention on possible explanation of long time emission from nonlinear photonic crystal. The basis of our consideration is papers [3, 4], those deal with soliton formation in several layers of 1D nonlinear photonic crystal. Because of this, the light wave can exist in photonic crystal a long time (in ideal case—infinite time interval). Taking into account a relation between soliton duration and its maximum intensity, the leaving of laser energy from the layer of photonic crystal takes place due not full reflection from boundaries of layer. The time of light emission for this case depends on nonlinear susceptibility of photonic crystal and the intensity of laser pulse. Hence, soliton formation inside the nonlinear elements of photonic crystal can be one of the reasons of long time emission. We got in computer simulation a long time emission of 1D (layered) and 2D (circular or rectangular elements) nonlinear photonic crystal under the action of laser pulse with femtosecond duration under the conditions of soliton formation in some elements of photonic crystal. Input intensity of laser pulse, at which a soliton appears in nonlinear photonic crystal, can be ten times less due to effects of enhancement of optical intensity in periodic structure [4, 5].

Nonlinear frequency conversion in two-dimensional nonlinear photonic crystals solved by a plane-wave-based transfer-matrix method

We develop the plane-wave-based transfer-matrix method, which is a formalism that has been extensively used to calculate the scattering of electromagnetic waves by usual linear photonic crystals, to solve the quasi-phase-matched (QPM) second-harmonic generation (SHG) in two-dimensional (2D) nonlinear photonic crystals. Using this method, we can calculate the conversion efficiency of high-order collinear and noncollinear QPM second-harmonics. We apply this method to evaluate the SHG conversion efficiency in the 2D periodically poled ${\text{LiNbO}}_{3}$ crystal with rectangular lattice. The high-order collinear and noncollinear QPM SHGs are observed. The wavelengths at which various orders of QPM SHGs occur and their relative conversion efficiencies predicted by the current theoretical method are in fairly good agreement with those found in experiments. This indicates that the developed method is effective and efficient in handling nonlinear light diffraction in nonlinear photonic crystals.

Optical limitation in two-dimensional nonlinear photonic crystal with triangular lattice

Optical limitation in a 2D nonlinear photonic crystal (NPC) has been studied in this Letter. Since the optical limitation is due to Bragg scattering induced by the variation of nonlinear refractive index, it is sure that the optical limitation can be realized in nonlinear photonic crystal. The light propagation characteristics in a two-dimensional nonlinear photonic crystal with triangular lattice has been calculated by using the finite-difference time-domain algorithm, which is constructed by placing certain number of nonlinear dielectric rods in a linear photonic crystal. The optical limiting effects at 1.300 and 0.504 μm have been obviously obtained for TE polarization and TM polarization, respectively.

Second-harmonic generation in hexagonally-poled lithium niobate slab waveguides

Slab nonlinear waveguides have been fabricated by annealing and reverse proton-exchange in hexagonally-poled lithium niobate (HexLN). The technology allowed the first demonstration of guided-wave quadratic interactions in 2D nonlinear photonic crystals.