Optical Ring Network Research Articles

Bound states in the continuum with giant Q-factor generating from one-dimensional symmetric defect ring optical waveguide networks

In this paper, we focus on achieving bound states in the continuum (BICs) in optical waveguide networks. For this purpose, we design a one-dimensional symmetric defect ring optical waveguide networks (1D SDROWNs) and extensively investigate the propagation characteristics of electromagnetic waves in this network. The results indicate that 1D SDROWNs can effectively generate BICs. By varying parameters such as the ratio of the waveguide length of the lower arm to that of the upper arm(RWLLAUA), the ratio of the refractive index of the lower arm to that of the upper arm (RRILAUA), or the number of cells of the system, we not only realize a giant quality factor (Q-factor), but also reveal the angular frequency and quantity characteristics of quasi-BICs. Remarkably, the optimally designed network in this study theoretically realizes a huge Q-factor exceeding 109, which is at least three orders of magnitude higher than the maximum Q-factor achieved in the reported experiments. Furthermore, we observe two types of electromagnetic wave singularities at the quasi-BICs angular frequencies: the quasi-BICs-induced periodic transmission oscillation varying with the number of unit cells, and the quasi-BICs-induced high transmittance and low transmittance varying with the RWLLAUA. These results have broad application prospects in fields such as optical information storage, optical logic and computation, optical modulators and switches, optical sensor networks, optical filters and multi-channel selectors.

Mechanism and properties of all-optical switching constructed from 1D symmetric defect ring optical waveguide network

In this paper, barium fluoride (BaF2) and bismuth doped silicon-rich silicon dioxide (Bi-doped Si-rich SiO2) are used for designing a novel pump-free ultracompact ultrahigh efficiency all-optical switching constructed from a photonic band gap (PBG) structure, the one-dimensional (1D) symmetric defect ring optical waveguide network (SDROWN) with integer-broken waveguide length ratio. The ultralow threshold control energy of our designing all-optical switching is 1.24556 × 10−25J, which makes the switching be pump-free. The transverse and longitudinal feature sizes of the switching are, respectively, 160 nm and 270 nm, which arrive at the level of the best reported results and makes the switching may realize intense integration. The ultrahigh switching efficiency arrives at 8.69565 × 107 and is more than 2 orders of magnitude larger than those of other kinds of all-optical switchings. The switching time is nearly 116fs, which arrives at the level of the best reported results. On the other hand, this technique may provide the probability for solving the four contradictions/difficulties in the designing of practical on-chip all-optical switching. It may deepen people's knowledge on PBG structures and provide new scientific bases for the designing of practical on-chip all-optical switching.

Singular optical propagation properties of two types of one-dimensional anti- PT -symmetric periodic ring optical waveguide networks

Two types of one-dimensional (1D) anti- PT -symmetric periodic ring optical waveguide networks, consisting of gain and loss materials, are constructed. The singular optical propagation properties of these networks are investigated. The results show that the system composed of gain materials exhibits characteristics of ultra-strong transmission and bidirectional reflection. Conversely, the system composed of loss materials demonstrates equal transmittance and reflectance at some frequencies. In both the systems, a new type of total reflection phenomenon is observed. When the imaginary part of the refractive indices of waveguide segments is smaller than 10−5, the system shows bidirectional transparency with the transmittance tending to be 1 and reflectivity to be smaller than 10−8 at some bands. When the refractive indices of the waveguide segments are real, the system will be bidirectional transparent at the full band. These findings may deepen the understanding of anti- PT -symmetric optical systems and optical waveguide networks, and possess potential applications in efficient optical energy storage, ultra-sensitive optical filters, ultra-sensitive all-optical switches, integrated optical chips, stealth physics, and so on.

All-optical switch with ultrahigh switching efficiency and ultralow threshold energy based on a one-dimensional PT-symmetric ring optical waveguide network

In this work, we propose an all-optical switch based on one-dimensional (1D) parity-time-symmetric (PT-symmetric) ring optical waveguide network (PTSROWN). By use of the resonant coupling effect of the PT-symmetric structure, the all-optical switch based on our designed 1D PTSROWN generates an ultrahigh transmissivity of 1.42×1018 at ON state, which breaks the bottleneck of the transmissivity of 1 at ON state produced by the all-optical switches made of dielectric optical waveguide networks, photonic crystals, microring resonators, and meanwhile, creates an ultralow transmissivity of 1.01×10−18 at OFF state. It causes our designing all-optical switch reproducing extraordinary large switch efficiency of 1.41×1036, which is 10 orders of magnitude greater than the optimal results reported yet. On the other hand, the super resonant coupling effects can also make the all-optical switch generate ultrastrong photonic localization at ON state, and then drastically reduce the threshold energy. In addition, we have deeply optimized the PT-symmetric optical waveguide network and obtain better extremum spontaneous PT-symmetric breaking points. On this condition, our designing all-optical switch can produce an ultralow threshold energy of 4.3×10−34 J, which is 12 orders of magnitude smaller than the best reported results. This not only provides a better choice for developing all-optical switching devices with better performance, but also possesses a broad application prospect in designing high-efficiency optical amplifiers, optical energy saver devices, etc.

Extraordinary Characteristics of One-Dimensional PT-Symmetric Ring Optical Waveguide Networks Composed of Adjustable Length Ratio Waveguides.

A novel one-dimensional parity-time-symmetric periodic ring optical waveguide network (1D PTSPROWN) is constructed using magnesium fluoride (MgF2), by adjusting the length ratio of gain and loss materials in PT-symmetric waveguide and ordinary dielectric material, and by optimizing the program to search for the extremum spontaneous PT-symmetric breaking points. The ultra-strong transmission, reflection, and photonic location are noticed in the proposed 1DPTSPROWN as compared with the other PT-symmetric optical waveguide networks. The maximum and minimum reached 1018 and 10−15, respectively, which is more than 6 orders of magnitude greater and 3 orders of magnitude smaller than the best results reported so far. The ultra-strong transmission and reflection peaks, ultra-weak transmission, and reflection valleys generated by electromagnetic waves in this network were found to have interesting resonance and anti-resonance effects. Furthermore, frequency of periodic cycles and violet or redshift laws were discovered in the 1D PTSPROWN of fixed length ratio of gain and loss material in the PT-symmetric waveguide by adjusting the ratio of the upper and lower arm lengths of waveguides. The proposed optical waveguide network might have potential application in the design of CPA lasers, high-efficiency optical accumulators, and several other devices.

Communication wavelength investigation of bound states in the continuum of one-dimensional two-material periodic ring optical waveguide network.

In this study, a one-dimensional (1D) two-material period ring optical waveguide network (TMPROWN) was designed, and its optical properties were investigated. The key characteristics observed in the 1D TMPROWN include the following: (1) Bound states in continuum (BICs) can be generated in the optical waveguide network. (2) In contrast to the BICs previously reported in optical structures, the range of the BICs generated by the 1D TMPROWN is not only larger, but also continuous. This feature makes it possible for us to further study the electromagnetic wave characteristics in the range of the BICs. In addition, we analyzed the physical mechanisms of the BICs generated in the 1D TMPROWN. The 1D TMPROWN is simple in structure, demonstrates flexibility with respect to adjusting the frequency band of the BICs, and offers easy measurement of the amplitude and phase of electromagnetic waves. Hence, further research on high-power super luminescent diodes, optical switches, efficient photonic energy storage, and other optical devices based on the 1D TMPROWN designed in this study is likely to have implications in a broad range of applications.

Wide-Sense Nonblocking Multicast in WDM Optical Linear Array and Ring Networks with 3-Length Extension Under Longest Link First Routing

The modern scientific growths in optical networks based on wavelength division multiplexing (WDM) are more attractive to satisfy the high bandwidth requirements of the modern internet infrastructure. Moreover, they potential to satisfy the future bandwidth requirements.WDM optical networks act as the backbone for telecommunication and high-performance communication networks. Multicast communication is the simultaneous transmission of data from one source node to many destination nodes available in the network over wavelength division multiplexing. It is extensively deployed in high performance computing and communication networks. In this article, a linear array and ring networks are extended by directly linking all nodes which are separated by two intermediate nodes with additional fibers which is referred as linear array and ring network with 3-length extension. The wavelength allotment methods are proposed to realize one-to-many communication over wavelength division multiplexing optical linear array and ring with 2-length extension under longest link first routing and the minimum wavelength number needed is determined. The minimum wavelength number needed to support for the extended linear array is reduced approximately by 20% when compared with that of a linear array network and for the extended unidirectional ring is reduced approximately by 25% when compared with that of a unidirectional ring network. And also, for the extended bidirectional ring the minimum wavelength number is reduced approximately by 33% when compared with that of bidirectional ring network.

Wide-Sense Nonblocking Multicast in WDM Optical Linear Array and Ring Networks with 2-Length Extension under Index Based Routing

Multicast communication is the concurrent transmission of data from one source node to many destination. It is widely deployed in high performance computing and communication networks.In this paper, a linear array and ring networks are extended by directly linking all nodes which are separated by one intermediate node with additional fibers which is referred as linear array and ring network with 2-length extension and wide sense nonblocking multicast is studied. The wavelength allotment methods are proposed to realize one-to-many communication over wavelength division multiplexing optical linear array and ring with 2-length extension under index-based routing and the minimum wavelength number needed is determined. The minimum wavelength number needed to support for the extended linear array and ring topologies is reduced approximately by half when compared with that of a linear array network and ring network.

Extraordinary optical characteristics of one-dimensional double anti-PT-symmetric ring optical waveguide networks

In this paper, a unique one-dimensional double anti-PT-symmetric ring optical waveguide network (1D DAPTSROWN) is designed whose refractive index satisfies n(x)=−n∗(−x). The extraordinary optical characteristics of the network are studied by means of the generalized Floquet–Bloch theorem, three-material network equation and generalized eigenfunction method. Due to the physical difference between the anti-PT-symmetric and PT-symmetric optical waveguide networks, the previous method of the PT-symmetric optical waveguide network is not applicable to the anti-PT-symmetric optical waveguide network designed in this paper. Thus, based on the previous method and the network equation, we propose a connection function to identify the extremum mode points in the anti-PT-symmetric optical waveguide network. At the extremum mode point, the optical waveguide network can produce extraordinary ultra-strong transmission, ultra-strong reflection, and ultra-strong photonic localizations. The corresponding calculated values in this paper arrives at 1028, which is much larger than 1012 (the best result reported previously). This shows that the anti-PT-symmetric network may have potential in applications in designing optical filters, optical amplifiers and so on.

Analysis of an optical SDM ring network model for applying MIMO processing

Optical multiple-input multiple-output (MIMO) technology is introduced into optical space division multiplexing (SDM) communication as an effective solution for the crosstalk issue. Unfortunately, this application is limited because all the channel information over the transmission link must be transmitted to MIMO receivers for complete crosstalk compensation, which indicates difficulty in applying MIMO to the transmission path via optical switches. We newly propose that one of the solutions to this limitation is a ring network because all channel information can be maintained in the ring. In particular, a typical ring network model comprising optical add-drop multiplexers (OADMs) and multicore fibers (MCFs) is introduced, and the ability of MIMO to compensate for capacity degradation because of the inter-core crosstalk is investigated. Moreover, the protection function, which is essential for the ring network, is also evaluated under the fiber and fiber core failures. As per the simulation results, although the protection operation affects the transmission capacity, the capacity loss is suppressed in the event of a failure to < 5%. We believe that these results provide useful information for designing SDM-based optical networks.

Optical Protection Cost of Loop Free Alternates on Completely Connected IP Networks Over Optical Rings

We consider protection switching in an IP over optical network. There is IP Fast Reroute Loop-free Alternates (IP FRR LFA) at the IP layer, and protection switching at the optical layer. Our network model assumes a completely connected IP network over an optical ring network that is required to protect a predetermined fraction of network bandwidth. This model leads to analytical formulas on network protection costs which we show are accurate. We also show that network cost is at or near zero when the network is required to protect at most 33% of traffic. A cost comparison to networks using MPLS Fast Reroute (MPLS FRR) further indicates that LFA is a feasible protection mechanism.

Extraordinary characteristics of one-dimensional PT-symmetric ring optical waveguide networks with near-isometric and isometric arms

We construct one-dimensional -symmetric ring optical waveguide networks with near-isometric and isometric arms and investigate their extraordinary optical properties. It is found that the features for the former and the latter are quite different, although extraordinary ultrastrong transmission and reflection exist in both of them. When the former changes to be the latter, the extraordinary optical properties will all change remarkably, and the fitting formulae are obtained. The bidirectional invisibility only exists in the former and the principle is analyzed. This work may be helpful for designing ultra-narrow optical filters, ultra-sensitive optical switches, and resonant component for high-monochromatic lasing.

Extraordinary propagation characteristics of electromagnetic waves in one-dimensional anti-PT-symmetric ring optical waveguide network**Project supported by the National Natural Science Foundation of China (Grant Nos. 11674107, 61475049, 11775083, 61875057, 61774062, and 61771205), the Natural Science Foundation of Guangdong Province, China (Grant No. 2015A030313374), and the Special Funds for the Cultivation of Guangdong College Students’ Scientifific and Techonlogical Innovation, China (Grant No.

In this paper, we design a one-dimensional anti-PT-symmetric ring optical waveguide network (1D APTSPROWN). Using the three-material network equation and the generalized Floquet–Bloch theorem, we investigate its photonic mode distribution, and observe weak extremum spontaneous anti-PT-symmetric breaking points (WBPs) and strong extremum spontaneous anti-PT-symmetric breaking points (SBPs). Then the transmission spectrum is obtained by using the three-material network equation and the generalized eigenfunction method. The 1D APTSPROWN is found to generate ultra-strong transmission near SBPs and ultra-weak transmission near WBPs and SBPs, with the maximal and minimal transmissions being 4.08× 1012 and 7.08× 10−52, respectively. The maximal transmission has the same order of magnitude as the best-reported result. It is not only because the distribution of photonic modes generated by the 1D APTSROWN results in the coupling resonance and anti-resonance, but also because the 1D APTSROWN composed of materials whose real parts of refractive indices are positive and negative has two kinds of phase effects, which results in the resonance and anti-resonance effects in the same kind of photonic modes. This demonstrates that the anti-PT-symmetric and PT-symmetric optical waveguide networks are quite different, which leads to a more in-depth understanding of anti-PT-symmetric and PT-symmetric structures. This work has the potential for paving a new approach to designing single photon emitters, optical amplifiers, and high-efficiency optical energy saver devices.

Wide-sense nonblocking multicast in WRMD WDM optical linear array and ring

Multicast communication is the simultaneous transmission of information from a single source to various destinations. It occurs extensively in telecommunication and advanced computing systems including enterprises operating datacenters. WDM optical networks act as the backbone for telecommunication and high performance networks. Wavelengths are scarce resources in WDM optical networks. Wavelengths usage in a network must be limited to decrease its cost and complexity. Optical linear array and ring networks find widespread application in interconnection networks including LAN and WAN. In this paper, wide-sense nonblocking multicast communication is analyzed in wavelength reusable multi-carrier distributed (WRMD) wavelength division multiplexing (WDM) linear array, unidirectional ring and bidirectional ring networks. The sufficient and necessary condition on the minimum wavelength number required for the network to be wide-sense nonblocking is derived for each of the above network topologies in the presence of a single multi-carrier light source (MCLS). An explicit wavelength allotment technique is also proposed for the above network topologies.

Fiber ring architecture implementation by using survivability techniques

In Communication Network(s) Physical Layer provides the path connectivity in a given network topology. In this protectioni.e. fault finding with respect to Link Failure and refurbishment in order to obtain Protection and Refurbishment Survivability Factor(PRSF). In optical network the switching capacity is controlled by Central Office(CO) or Manually, In order to be cost effective among different fiber network architecture such as 1:1, R:N. In the first category it applies theoretically, where as in R:N level the Fiber Cable (FC) is well protected in the form of Passive Active Optical Ring Network(PAORN) to its central switched architecture. In this Optical Elements(OE), Optical Devices(OD) are well used for Protection Refurbishment Triggering Mode(PRTM). In passive ring network is designed and implemented by using Optical Signal Protection Scheme (OSPS). In this paper further the feasibility of Fiber Loop Network Architecture (FLNA) is well compared by using Point-to-Point Passive Active Signal Transportation Mechanism (PPPASTM).

Theoretical Design of a Pump‐Free Ultrahigh Efficiency All‐Optical Switching Based on a Defect Ring Optical Waveguide Network

AbstractA theoretical design of a defect ring optical waveguide network is proposed to construct a pump‐free ultrahigh efficiency all‐optical switch. This switch creates ultrastrong photonic localization and causes the nonlinear dielectric in the defect waveguide to intensely respond. At its ON state, this material defect without Kerr response helps to produce a pair of sharp pass bands in the transmission spectrum to form the dual channel of the all‐optical switch. When it is switched to its OFF state, the strong Kerr response induced refractive index change in the high nonlinear defect waveguide strongly alters the spectrum, leading to a collapse of the dual channels. Network equation and generalized eigenfunction method are used to numerically calculate the optical properties of the switch and obtain a threshold control energy of about 2.90 zJ, which is eight orders of magnitude lower than previously reported. The switching efficiency/transmission ratio exceeds 3× 1011, which is six orders of magnitude larger than previously reported. The state transition time is nearly 108 fs, which is approximately two orders of magnitude faster than the previously reported shortest time. Furthermore, the switch size can be much smaller than 2.6 µm and will be suitable for integration.

Extraordinary characteristics for one-dimensional parity-time-symmetric periodic ring optical waveguide networks

In this paper, we design a one-dimensional (1D) parity-time-symmetric periodic ring optical waveguide network (PTSPROWN) and investigate its extraordinary optical characteristics. It is found that quite different from traditional vacuum/dielectric optical waveguide networks, 1D PTSPROWN cannot produce a photonic ordinary propagation mode, but can generate simultaneously two kinds of photonic nonpropagation modes: attenuation propagation mode and gain propagation mode. It creates neither passband nor stopband and possesses no photonic band structure. This makes 1D PTSPROWN possess richer spontaneous PT-symmetric breaking points and causes interesting extremum spontaneous PT-symmetric breaking points to appear, where electromagnetic waves can create ultrastrong extraordinary transmission, reflection, and localization, and the maximum can arrive at 6.6556×1012 and is more than 7 orders of magnitude larger than the results reported previously. 1D PTSPROWN may possess potential in designing high-efficiency optical energy saver devices, optical amplifiers, optical switches with ultrahigh monochromaticity, and so on.

Hybrid artificial bee colony algorithm based approaches for two ring loading problems

This paper presents hybrid artificial bee colony algorithm based approaches for two \(\mathcal {NP}\)-hard problems arising in optical ring networks. These two problems falls under the category of ring loading problems. Given a set of data transfer demands between different pair of nodes, the first problem consists in routing the demands on the ring in either clockwise or counter-clockwise directions so that the maximum data transmitted through any link in either directions is minimized. The second problem, on the other hand, discriminates between the data transmitted in one direction from the other and consists in minimizing the maximum data transmitted in one particular direction through any link. The first problem is referred to as weighted ring edge-loading problem in the literature, whereas the latter as weighted ring arc-loading problem. Computational results on the standard benchmark instances show the effectiveness of our approaches on both the problems.

Noncoherent spectral optical CDMA system using 1-D multi method codes in one optical ring network

We propose the new family of newly constructed codes named the one-dimensional Multi method codes (1-D MM codes) in the spectral amplitude coding optical code division multiple access (SAC-OCDMA) system. The new 1-D MM codes have the auto-cross correlation constraint and cross correlation constraint to be p and zero, respectively. Furthermore, the 1-D MM codes use the easy proposed structure. The proposed structure can use each transmitter, optical connected ring set (OCRS), and each receiver to become the one optical ring network. The proposed system uses the control path to give the user controller, correct optical fiber controller and failure optical fiber controller to achieve the one optical ring network. The numerical results demonstrate that the bit error rate (BER) in the proposed system using the 1-D MM codes outperform that in other systems using the 1-D M Sequence codes, 1-MQC codes, and 1-D RSQC codes. Then, the data transmission rate of the 1-D MM codes can achieve the 2.5 Gbps.

Investigation of Power Transients in 45 Channel DWDM Ring Optical Network

Erbium doped fiber amplifiers (EDFA) are most commonly used in optical networks for the most assorted applications. The fast power transient effect of the cascaded erbium-doped fiber amplifiers (EDFA) in 45 channels optical ring network is investigated. The power transient effect of EDFA’s are observed when channels are added and dropped. It is shown that, for low channel adding/dropping frequency closed to EDFA transient rate, the transmission performances of the surviving channels are impaired severely. And also ring laser configuration technique has been reported to mitigate the effect of power transients. Optsim simulation was utilized for simulation of the designed DWDM OADM ring network.