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A Highly Birefringent and Nonlinear AsSe<formula><tex>$_{2}$</tex></formula>-As<formula><tex>$_{2}$</tex></formula>S<formula><tex>$_{5}$</tex></formula> Photonic Crystal Fiber with Two Zero-Dispersion Wavelengths
摘要： A hybrid AsSe2–As2S5 photonic crystal ?ber (PCF) with a solid elliptical core is proposed and studied theoretically by the full-vector ?nite element method. The core and cladding of the PCF are made of AsSe2 and As2S5 glasses, respectively. Simulation results demonstrates that, at the operating wavelength of 1.55 μm, the proposed PCF not only exhibits a very high birefringence of 0.091 but also has large nonlinear coef?cients of 147.8 and 78.2 W ?1m ?1 for the X- and Y-polarized (X and Y-pol) modes, respectively. Moreover, it is able to achieve two zero-dispersion wavelengths for both the X-pol (1.52 and 2.19 μm) and Y-pol (1.43 and 2.12 μm) modes. The proposed hybrid PCF exhibits excellent polarization maintaining and the nonlinearity performance, thus, suitable to be used in supercontinuum spectrum generation and polarization maintaining nonlinear signal processing.
关键词： zero-dispersion wavelength,High birefringence,supercontinuum spectrum generation,photonic crystal ?ber,nonlinearity
更新于2025-09-23 15:22:29
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Design and Evaluation of Optical Circuit Switches for Intra-Datacenter Networking
摘要： With the rapid growth in intra-datacenter traffic, the high power consumption stemming from the huge number of electrical switches is becoming a critical issue. Hence, high-port-count optical circuit switches are urgently needed. In this paper, we overview recently developed optical circuit switch architecture based on two-dimensional switches, i.e., space switches and wavelength-routing switches. The attainable maximum switch port counts and hardware requirements are quantitatively evaluated through extensive computer simulations that consider 10-Gbps intensity modulation with direct detection systems, 43-Gbps differential quadrature phase shift keying with self-coherent detection systems, and 128-Gbps dual-polarization quadrature phase shift keying with coherent detection systems. The simulation results confirm the existence of switching architecture that can accommodate more than 1,000 ports with relatively light hardware requirements.
关键词： wavelength routing,optical circuit switch,Datacenter network
更新于2025-09-23 15:22:29
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Suppression of four-wave mixing in a 22?×?10?Gbps dense wavelength division multiplexed system by linearly chirped fiber Bragg gratings
摘要： A scheme comprising two linearly chirped fiber Bragg gratings (LCFBGs) is proposed to suppress four-wave mixing (FWM) effects in a 22×10? Gbps dense wavelength division multiplexed (DWDM) system employing dispersion shifted fiber with 0.2? nm channel spacing. The FWM reduction in our proposed scheme has been studied by varying the input signal power per channel from ? 2 to + 10? dBm. The parameters of LCFBGs are optimized to obtain a maximum quality factor for all 22 channels. The proposed method is effective even at high input power (10?dBm) and provides a simple, cost effective way to improve the transmission performance in DWDM system.
关键词： Dense wavelength division multiplexing (DWDM),Dispersion,Four wave mixing (FWM),Chirped fiber Bragg gratings,Channel spacing
更新于2025-09-23 15:21:21
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ELECTRODELESS MEASUREMENT TECHNIQUE OF COMPLEX DIELECTRIC PERMITTIVITY OF HIGH-K DIELECTRIC FILMS IN THE MILLIMETER WAVELENGTH RANGE
摘要： An electrodeless measurement technique of complex dielectric permittivity of high-K dielectric ?lms is described. The technique is based on a quasi-optic Fabry-Perot resonator and modi?ed for investigation of two-layer dielectric structures — substrate/K-?lm. This procedure is destined to be used for providing a simple intermediate control of parameters of high-K ?lms before the following technological process. Regimes of measurements providing the most sensitive conditions for de?nition of ?lm parameters are considered. The proposed method is tested on two-layer structures with well-known parameters and is used for characterization of ferroelectric (Ba,Sr)TiO3 ?lms in the millimeter wavelength range (～ 50 GHz).
关键词： Fabry-Perot resonator,complex dielectric permittivity,electrodeless measurement,millimeter wavelength range,high-K dielectric films
更新于2025-09-23 15:21:21
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Label Stacking Scenarios in Hybrid Wavelength and Code-Switched GMPLS Networks
摘要： Multi-protocol label switching (MPLS) is a promising solution to implement high-speed internet protocol (IP) networks by reducing the layer number. To meet the increasing demand for data traffic, optical packet switching (OPS) is integrated under IP to provide high bandwidth to end users. Generalized MPLS (GMPLS) is perfectly compatible with the routing algorithm in IP/MPLS as it supports packet-switching functions. In this paper, we investigate the label stacking scenarios in GMPLS networks. In GMPLS, label stacking is done to reduce the node complexity by appending multiple labels to a single packet. Wavelength-division multiplexing (WDM) and optical code-division multiplexing (OCDM) signals have been widely used as identifying labels. As the labels can be permutated among the wavelengths or code dimensions, the structure of a label stack can be varied. However, studies on the relationship between label stacking scenarios and network performance are limited. To investigate this issue, we propose three label stacking models: sequential code distribution; sequential wavelength distribution, and random label distribution. The simulation results show that the sequential wavelength assignment, wherein the labels are uniformly distributed among the wavelengths, exhibits the best system performance in terms of the label-error rate (LER).
关键词： label stacking,generalized multi-protocol label switching (GMPLS),wavelength-division multiplexing (WDM),optical code-division multiplexing (OCDM)
更新于2025-09-23 15:21:21
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Low-profile wideband Fabry-Perot resonator antenna using artificial magnetic conductor surface
摘要： A low-profile, high gain Fabry-Perot Resonator antenna with a wide operation bandwidth (BW) is presented in this paper. The proposed design consists of an ellipse-shaped dipole as a wideband radiating source, which is reflected by an artificial magnetic conductor ground plane to achieve low-profile structure. The antenna gain can be significantly enhanced by the use of a half-wavelength-thick dielectric slab as a partial reflecting surface. Additionally, this dielectric slab also contributes to improving the radiation pattern characteristics of the proposed design, especially in the high frequency region. A final prototype with an overall size of 1.2λL × 1.2λL × 0.4λL (λL is free-space wavelength at the lowest frequency of 3-dB gain BW) has been fabricated to validate the concept. The measured results show that the proposed antenna yielded a wide 3-dB gain BW of approximately 50.3% with a peak gain of 14 dBi and impedance matching BW of 48.9%.
关键词： high gain,wideband,artificial magnetic conductor,half-wavelength dielectric slab,Fabry-Perot antenna,low profile
更新于2025-09-23 15:21:21
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Point-by-Point Femtosecond-Laser Inscription of 2-μm-Wavelength-Band FBG through Fiber Coating
摘要： We propose a point-by-point inscription method for fiber Bragg grating (FBG) fabrication using a femtosecond pulsed laser focused through a fiber polyimide coating, realizing a 2-μm-wavelength-band FBG. A femtosecond laser acts as the inscription laser, focused by a 63× oil lens. A first-order FBG was fabricated with a grating interval of 700 nm. The 15- μW pulsed laser was focused directly on the fiber core through the polyimide coating and cladding. A first-order FBG for 2004.8-nm light with more than 56% reflectances was fabricated. High wavelength sensitivity and linearity of the FBG were demonstrated by temperature and strain-sensing testing. The first-order FBG of 2004.8 and 2000.2 nm resonant wavelengths could be realized simultaneously through parallel inscription method in 3000μm long grating area.
关键词： 2-μm-wavelength-band,Fiber Bragg grating,Erbium-doped fiber laser,Femtosecond pulsed laser
更新于2025-09-23 15:21:21
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Alien Wavelengths Over Optical Transport Networks
摘要： To reduce network infrastructure cost, network operators want to integrate interoperable and open transponders, since these transponders allow application of the latest technologies over legacy networks at a competitive price. This process of using third-party transponders in a given network is commonly called “alien wavelength” support. Yet, moving toward interoperability raises several challenges: incompatible physical parameters, vendor lock-in, and proprietary software. Manual set up of alien wavelengths has been demonstrated, but automating this process is essential to enable alien wavelength operation in the field. This paper sheds light on the prevailing literature on the concept of alien wavelengths, taking into account many challenges that accompany the concept on its various levels. We particularly focus on several approaches proposed in the literature: protocol message translation, controller cooperation, and open line systems, including our own proposals, an OpenROADM-based approach and a RSVP-TE-based approach. We analyze these approaches with respect to several criteria: applicability to legacy equipment, added operational cost, and the offered level of interoperability and openness. According to these characteristics, we note that, even though some non-interoperable approaches might be applicable to legacy equipment and easy to maintain, they remain infeasible with advanced alien scenarios (high level of interoperability). Finally, a combination has to be made between at least two of the given approaches in order to get the optimal solution.
关键词： Optical networks,Network interoperability,Alien wavelength
更新于2025-09-23 15:21:21
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Development and Validation of Spectrophotometric and Spectrofluorimetric Methods for the Determination of Cyclobenzaprine HCl
摘要： Five simple and sensitive methods were developed for the determination of cyclobenzapirine hcl (CB) in presence of its degradation product anthraquinone (AQ). Method A dual wavelength spectrophotometry (DW); where two wavelengths were selected for the drug 283 and 306 nm in such a way that the difference in absorbance was zero for its degradation. Method B ratio difference spectrophotometry (RD) was depended on measuring the ratio difference between 290 and 305 nm. Method C was depended on measuring the peak amplitude of the first derivative of the ratio spectra (1DD) at 282 and 306 nm. Method D Isoabsorptive Point (ISO) at 280 nm Coupled with Second Derivative (2D). Method E depending on spectrofluorimetric determination of cyclobenzapirine HCl through quenching of uranyl acetate with ?exi 228 nm and ?em at 458 nm. Linearties were obtained in concentration range 5 μg/ml – 30 μg/ml in case of methods A, B, C and D, while in case of methods E linearity was obtained in concentration range of 1 μg/ml –10 μg/ml. The five methods were found to be specific for CB in presence of different concentration % of its degradation product. The five proposed methods were successfully applied for the determination of CB in Multirelax tablets. Statistical comparison between the results obtained by the proposed methods and that obtained by the official one for the determination of the drug was done, founding that there were no significant differences between them.
关键词： (1DD) Derivative ratio,Dual wavelength (DW),Isoabsorptive point (ISO),Spectrofluorimetry,Ratio difference (RD),Uranyl acetate,Cyclobenzapirine HCl (CB),Anthraquinone (AQ)
更新于2025-09-23 15:21:21
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Switchable Multi-Color Solution-Processed QD-laser
摘要： In this paper, for the first time, the switchable two-color quantum dot laser has been realized considering solution process technology, which has both simultaneous and lonely lasing capability exploiting selective energy contacts. furthermore, both channels can be modulated independently, which is a significant feature in high-speed data transmission. To this end, utilizing superimposed quantum dots with various radii in the active layer provides the different emission wavelengths. In order to achieve the different sizes of QDs, solution process technology has been used as a cost-effectiveness and fabrication ease method. Moreover, at the introduced structure to accomplish the idea, the quantum wells are used as separate selective energy contacts to control the lasing channels at the desired wavelength. It makes the prominent device have simultaneous lasing at different emission wavelengths or be able to lase just at one wavelength. the performance of the proposed device has been modeled based on developed rate equation by assuming inhomogeneous broadening of energy levels as a consequence of the size distribution of quantum dots and considering tunnel injection of carriers into the quantum dots via selective energy contacts. Based on simulation results, the simultaneous lasing in both or at one of two wavelengths 1.31 μm and 1.55 μm has been realized by the superimposition of two different sizes of InGaAs quantum dots in a single cavity and accomplishment of selective energy contacts. Besides, controlling the quantum dot coverage leads to managing the output power and modulation response at the desired wavelengths. By offering this idea, one more step is actually taken to approach the switchable QD-laser by the simple solution process method.
关键词： solution process technology,high-speed data transmission,multi-wavelength lasing,quantum dot laser,selective energy contacts
更新于2025-09-23 15:21:01