Optical Communications Research Papers - Academia.edu (original) (raw)

2025, Journal of Optical Communications

We report evaluation of first higher order modal field for dual mode optical fiber having step and parabolic index profiles. The study is carried out both in absence as well as in presence of Kerr nonlinearity. The analysis is based on a simple iterative method involving Chebyshev formalism. Taking some typical step- and parabolic-index fibers as examples, we show that our results agree excellently with the exact results which can be obtained by applying rigorous methods. Thus, our simple formalism stands the merit of being considered as an accurate alternative to the existing cumbersome methods. The prescribed formalism provides scope for accurate estimation of different propagation parameters associated with first higher order mode in such kinds of fibers in presence of Kerr nonlinearity. The execution of formalism being user friendly, it will be beneficial to the system engineers working in the field of optical technology.

2025, Journal of Optical Communications

The power series formulation for modal field of single-mode graded index fibers by Chebyshev technique has worked excellently in predicting accurately different propagation characteristics in simple fashion. Here we develop a simple iterative method involving Chebyshev formalism to predict the modal field of single-mode graded index fiber in the presence of Kerr-type nonlinearity. Taking step and parabolic index fibers as typical examples, we show that our results match excellently with the available exact results obtained vigorously. Thus, the reported technique can be considered as an accurate alternative to the existing cumbersome techniques. Accordingly, this formalism will be beneficial to the technologies for evaluation of modal noise in single-mode Kerr-type nonlinear graded index fibers.

2025, Journal of Optical Communications

We employ ABCD matrix formalism in order to investigate the coupling optics involving laser diode to single-mode circular core parabolic index fiber excitation via upside-down tapered hyperbolic microlens on the fiber tip. Analytic expressions for coupling efficiencies both in absence and in presence of transverse and angular mismatches are formulated. The concerned investigations are made for two practical wavelengths namely 1.3 µm and 1.5 µm. The execution of the prescribed formulations involves little computation. It has been found that the wavelength 1.5 µm is more efficient in respect of coupling. It is also seen that the present coupling device at both the wavelengths shows more tolerance with respect to angular mismatch. As regards tolerance with respect to transverse mismatch, the result is poor at both the wavelengths used. Consequently, it is desirable that designers should not to exceed transverse mismatch beyond 1 μm.

2025

In the Internet of services, information technology (IT) infrastructure providers play a critical role in making the services accessible to end-users. IT infrastructure providers host platforms and services in their datacenters (DCs). The cloud initiative has been accompanied by the introduction of new computing paradigms, such as Infrastructure as a Service (IaaS) and Software as a Service (SaaS), which have dramatically reduced the time and costs required to develop and deploy a service. However, transport networks become crucial to make services accessible to the user and to operate DCs. Transport networks are currently configured with big static fat pipes based on capacity over-provisioning aiming at guaranteeing traffic demand and other parameters committed in Service Level Agreement (SLA) contracts. Notwithstanding, such over-dimensioning adds high operational costs for DC operators and service providers. Therefore, new mechanisms to provide reconfiguration and adaptability of...

2025, Scientific Reports

Unlike conventional photon lasing, in which the threshold is limited by the population inversion of the electron-hole plasma, the exciton lasing generated by exciton-exciton scattering and the polariton lasing generated by dynamical condensates have received considerable attention in recent years because of the sub-Mott density and low-threshold operation. This paper presents a novel approach to generate both exciton and polariton lasing in a strongly coupled microcavity (MC) and determine the critical driving requirements for simultaneously triggering these two lasing operation in temperature <140 K and large negative polariton-exciton offset (<−133 meV) conditions. In addition, the corresponding lasing behaviors, such as threshold energy, linewidth, phase diagram and angular dispersion are verified. The results afford a basis from which to understand the complicated lasing mechanisms in strongly coupled MCs and verify a new method with which to trigger dual laser emission ba...

2025, Light: Science & Applications

The strong light-matter interaction in ZnO-embedded microcavities has received great attention in recent years, due to its ability to generate the robust bosonic quasiparticles, exciton-polaritons, at or above room temperature. This review introduces the strong coupling effect in ZnO-based microcavities and describes the recent progress in this field. In addition, the report contains a systematic analysis of the room-temperature strong-coupling effects from relaxation to polariton lasing. The stable room temperature operation of polaritonic effects in a ZnO microcavity promises a wide range of practical applications in the future, such as ultra-low power consumption coherent light emitters in the ultraviolet region, polaritonic transport, and other fundamental of quantum optics in solid-state systems.

2025, Proceedings of SPIE - The International Society for Optical Engineering

The characteristics of exciton-polaritons in ZnO-based microcavities (MCs) are demonstrated with a large vacuum Rabi splitting due to large exciton binding energy and oscillator strength. The lower polariton branches (LPBs) can be clearly observed. For low temperature and large negative detuning conditions, a clear polariton relaxation bottleneck in bulk ZnO-based MCs has been observed in angle-resolved photoluminescence measurements from 100 to 353 K at different cavity-exciton detunings. The bottleneck is strongly suppressed with increasing the temperature and pumping power and reducing detuning. This observed results supposed to be due to more efficient phonon-assisted relaxation and a longer radiative lifetime of the polaritons. In addition, the linewidth broadening, blue-shift of the emission peak, and polarization of polariton lasing from below threshold to up threshold are also discussed.

2025, Electronics Letters

2" modified prime codes are designed for all-optical code-division multiple access (CDMA) networks using very simple encoders and decoders. The proposed code is obtained from an original 2" prime code of prime number P, by padding P ~ 1 zeros in each 'subsequence' of codewords in the corresponding 2" prime code. The cross-correlation constraint of the resulting 2" modified prime code is equal to one, as opposed to two for a 2" prime code. For a given bit error rate (BER), the proposed code can thus be used to support a larger number of active users in the fibre optic CDMA network than a 2" prime code. Moreover, using the former can also reduce code length and weight compared with employing the latter to achieve the same BER.

2025

My deepest appreciation goes to my advisor, Dr. Gee-Kung Chang. I am grateful for his guidance through out my research at Georgia Tech. I could not have imagined having a better advisor and mentor for my Ph.D. Without his support and encouragement, I would never have finished. My co-advisor Dr. Jianjun Yu, who has a great part in shaping my research work and helped me tremendously at every step forward. He has been a source of inspiration for me. I also thank Prof. Chang and Dr. Yu for carefully going through my publication drafts, correcting my presentations, and helping me learn the various skills of academic research. I also thank my committee members Dr. Chuanyi

2025, 1ST SAMARRA INTERNATIONAL CONFERENCE FOR PURE AND APPLIED SCIENCES (SICPS2021): SICPS2021

2025, Optical and Quantum Electronics

For any photonic device simulation, the accuracy of the numerical solution not only depends on the methods being used but also on the discretization parameters used in that numerical method. In this work, Finite Element Method and Finite Difference Time Domain Method based on Maxwell's equations were used to simulate optical waveguides and directional couplers. As the solution accuracy may also depend on the index contrast used in such photonic devices, the characteristics of low-index contrast Germanium doped Silica and high-index contrast Silicon Nanowire Waveguides were analyzed, evaluated and benchmarked. Numerical results to benchmark Directional Couplers are also reported in this paper.

2025, OSA Continuum

In the past, multimode transmission through fibers has not been considered a preferred means of signal propagation due to the intermodal dispersion, which limits the data rate. However, recently, there has been an interest in using different modes as individual channels to increase the overall data rate. However, the challenging task in implementing such a system is that each individual mode has to be excited separately without mixing, and these should remain separated even at the bents and splices, and finally, they need to be collected separately. In this paper, design and optimization of a compact optical mode splitter by introducing a small slot in a silicon nanowire waveguide is demonstrated by employing a full-vectorial finite element method. The authors report here that by creating a slot within a waveguide, the desired coupling length ratio of 1:2 between the fundamental and the second modes can be obtained. The waveguide junctions have also been analyzed by using a rigorous least squares boundary residual method to study power transfer efficiency and effect of fabrication tolerances.

2025

Diversified, and high data rate communications are critical for the growing number of current and future small satellites providing the next generation of high-resolution science observations. Science Enabling Technologies for Heliophysics (SETH) is a small satellite mission co n c ep t 1 that will u t i l i ze F ib e r t ek ’ s l o w co s t , Compact Laser Communication Terminal (CLCT) to demonstrate high rate optical communications from deep space. This cutting-edge technology will support the Helio Energetic Neutral Atom (HELENA) heliophysics instrument t h a t demonstrates solar e n e r g e t i c n e u t r a l a t o m ( ENA) and space weather observation capabilities, in alignment with NASA’s Moon to Mars exploration initiative. SETH will demonstrate data rates of at least 10 Mbps from 0.1 AU. The CLCT includes a telescope, Pointing, Acquisition and Tracking sensor, vibration isolation mounts, and a fine steering mirror, all fitting in a 2U commercially available stack. SETH wil...

2025, Optics Letters

We present a novel and simple technique for obtaining transversal filters with negative coefficients by using uniform fiber Bragg gratings. We demonstrate a wide tuning range, good performance, low cost, and easy implementation of multitap filters in an all-optical passive configuration in which negative taps are obtained by use of the transmission of a broadband source through uniform Bragg gratings.

2025, Chinese Optics Letters

We propose an LED reshaping lens design for a handheld underwater wireless optical system to solve the problem of targeting the receiver. The simulation results shows that the designed lens can achieve 0.91 light intensity uniformity and 91.39% optical efficiency in hemisphere space, even with the actual LED model. After fabrication with computer numeric control, the work demonstrates the design to be effective.

2025, Photonics

Data centers are continuously growing in scale and can contain more than one million servers spreading across thousands of racks; requiring a large-scale switching network to provide broadband and reconfigurable interconnections of low latency. Traditional data center network architectures, through the use of electrical packet switches in a multi-tier topology, has fundamental weaknesses such as oversubscription and cabling complexity. Wireless intra-data center interconnection solutions have been proposed to deal with the cabling problem and can simultaneously address the over-provisioning problem by offering efficient topology re-configurability. In this work we introduce a novel free space optical interconnect solution for intra-data center networks that utilizes 2D optical beam steering for the transmitter, and high bandwidth wide-area photodiode arrays for the receiver. This new breed of free space optical interconnects can be developed on a photonic integrated circuit; offerin...

2025, IEEE Transactions on Instrumentation and Measurement

2025, Journal of Optical Communications

Peak to average power ratio (PAPR) is one of the major limitations of orthogonal frequency division multiplexing (OFDM) systems because the higher PAPR induces the signal to get out of linear region of high power amplifier (HPA). In this article, a hybrid PAPR reduction scheme based on the combination of optimized iterative clipping and filtering (OICF) method and phase rotation is proposed. Using phase rotation, signal’s initial PAPR has been reduced by 14.23 dB and then OICF further reduces the final PAPR by 1.37 dB. Decreased PAPR will play an important role in reducing systems power consumption.

2025, Journal of Telecommunication, Electronic and Computer Engineering

Carrierless amplitude phase (CAP) modulation format has appeared as a potential advanced modulation format candidate for spectrally efficient single-carrier modulation type due to less complexity and has competitive performance. In this paper, the comparison between 2D-CAP-4 and 4-QAM-DMT modulation format over 3 km single mode fiber (SMF) transmission link using 1310 nm vertical cavity surface emitting laser (VCSEL) has been performed for inhome network environment. The net bit rates of 625 Mb/s and 454.6 Mb/s are achieved for 2D-CAP-4 and 4-QAM-DMT, respectively. Spectral efficiencies of 1.89 b/s/Hz for 2D-CAP-4 and 1.43 b/s/Hz for 4-QAM-DMT are reported. It is observed that 2D-CAP-4 outperforms 4-QAM-DMT with 1.14 dB better receiver sensitivity. These results indicate that the privilege properties of CAP modulation format can be an attractive prospect for in-home network environment.

2025

Exploration of advanced modulation formats and multiplexing techniques for next generation optical access networks are of interest as promising solutions for delivering multiple services to end-users. This thesis addresses this from two different angles: high dimensionality carrierless amplitudephase (CAP) and multiple-input multiple-output (MIMO) radio-over-fiber (RoF) systems. High dimensionality CAP modulation has been investigated in optical fiber systems. In this project we conducted the first experimental demonstration of 3 and 4 dimensional CAP with bit rates up to 10 Gb/s. These results indicate the potentiality of supporting multiple users with converged services. At the same time, orthogonal division multiple access (ODMA) systems for multiple possible dimensions of CAP modulation has been demonstrated for user and service allocation in wavelength division multiplexing (WDM) optical access network. 2 × 2 MIMO RoF employing orthogonal frequency division multiplexing (OFDM) with 5.6 GHz RoF signaling over all-vertical cavity surface emitting lasers (VCSEL) WDM passive optical networks (PONs). We have employed polarization division multiplexing (PDM) to further increase the capacity per wavelength of the femto-cell network. Bit rate up to 1.59 Gbps with fiber-wireless transmission over 1 m air distance is demonstrated. The results presented in this thesis demonstrate the feasibility of high dimensionality CAP in increasing the number of dimensions and their potentially to be utilized for multiple service allocation to different users. MIMO multiplexing techniques with OFDM provides the scalability in increasing spectral efficiency and bit rates for RoF systems. High dimensional CAP and MIMO multiplexing techniques are two promising solutions for supporting wired and hybrid wired-wireless access networks. i First of all, I would like to attribute my sincere gratitude to my supervisor and co-supervisor, Professor Idelfonso Tafur Monroy and Assistant Professor Jesper Bevensee Jensen for their encouragement, support and enthusiasm. They always spent time with me and guided me through the problems that I have encountered. It is a privilege to work with them. Thanks a lot from my heart. I am very grateful to the Ministry of Higher Education of Malaysia (MOHE) and University of Tun Hussein Onn Malaysia (UTHM) for providing me with a scholarship. I would not have completed a Ph.D without this financial assistance. My warmest thanks are extended to my closest friend Lei, Xu, Xiaodan, and Ying. We have spent time together in the lab doing the experiment with a very good team working spirit. My sincere thanks to Kamau and Xianbin for their practical assistance. I would also like to thank all my colleagues at Metro-Access group, Darko, JJ, Neil, Alexey, Thang, Valeria, Roberto, Robert, Silvia, Alexander, Bomin, Miguel, David and also my colleagues in DTU Fotonik. I must also thank Evarist my ex-officemate in building 343 DTU Fotonik for sharing all the good food recipes. I want to thank to all my Malaysian friends in Denmark for friendship through all these years. Many thanks for supporting each other, and I really hope this friendship will last forever. The last, and foremost, I would like to thank my parents, mother in law, my brothers, my husband, Shamsudin Bin Awang and my two handsome heroes: Muhammad Hazlam and Muhammad Hulaif. Thanks for their 'dua', love, patience, and encouragement. This made my Ph.D study possible and joyful at DTU Fotonik.

2025, Chinese Optics Letters

In this Letter, an efficient bidirectional differential phase-shift keying (DPSK)-DPSK transmission for a ultradense wavelength division-multiplexed passive optical network is proposed. A single distributed feedback laser at the optical network unit (ONU) is used both as the local laser for downlink coherent detection and the optical carrier for uplink. Phase-shift keying is generated using a low-cost reflective semiconductor optical amplifier (RSOA) at the ONU. The RSOA chip has the bandwidth of 4.7 GHz at the maximum input power and bias current. For uplink transmission, the sensitivity of the RSOA chip reaches -48.2 dBm at the level of bit error rate ¼ 10 -3 for back-to-back, and the penalty for 50 km transmission is less than 1 dB when using polarization diversity.

2025, Light: Science & Applications

Light sources based on reliable and energy-efficient light-emitting diodes (LEDs) are instrumental in the development of solid-state lighting (SSL). Most research efforts in SSL have focused on improving both the intrinsic quantum efficiency (QE) and the stability of light emitters. For this reason, it is broadly accepted that with the advent of highly efficient (QE close to 1) and stable emitters, the fundamental research phase of SSL is coming to an end. In this study, we demonstrate a very large improvement in SSL emission (above 70-fold directional enhancement for p-polarized emission and 60-fold enhancement for unpolarized emission) using nanophotonic structures. This is attained by coupling emitters with very high QE to collective plasmonic resonances in periodic arrays of aluminum nanoantennas. Our results open a new path for fundamental and applied research in SSL in which plasmonic nanostructures are able to mold the spectral and angular distribution of the emission with unprecedented precision.

2025, Journal of the Optical Society of America B

For convenient optical communications by the aid of vortex beams, topological charge (TC) alterations should be translated to the change in intensity of the output light. In this paper, we formulate and experimentally investigate diffraction of vortex beams from amplitude radial gratings having sinusoidal profiles. We show that the diffraction pattern simply renders both TC and twist direction of the impinging vortex beam. When the TC of the vortex beam and the radial grating spoke number are equal, intensity on the optical axis of the Fraunhofer pattern gets a maximum value. Otherwise, its value on the optical axis remains zero. We examined the method on different vortex beams; the measured TCs of generated beams are in excellent agreement with the expected values. We show that an alteration between two vortex beams, in which one has a TC equal to the grating spoke number, is translated to a binary change in intensity of the output light on the optical axis. This feature might find wide applications in optical communications.

2025, Optics Express

This paper presents and demonstrates a centralized light source optical access network based on optical polarization multiplexing technique. By using two optical sources emitting light orthogonally polarized in the Central Node for downstream and upstream operations, the Remote Node is kept source-free. EVM values below telecommunication standard requirements have been measured experimentally when bidirectional digital signals have been transmitted over 10 km of SMF employing subcarrier multiplexing technique in the electrical domain.

2025, J. Opt. Commun.

This paper studies the bit error performance analysis of decode-and-forward (DF) relays-based freespace optical (FSO) communication systems using avalanche photodiode (APD). The system uses subcarrier intensity binary phase shift keying (BPSK) modulated signals and subjects to scintillation due to optical turbulence. A log-normal random process is considered to model the received signal intensity fluctuation for a clearair condition (weak atmospheric turbulence) scenario. Mathematical expressions of the average bit error probability and bit error rate (BER) are derived by taking into account the impact of atmospheric loss, thermalnoise and shot-noise limited conditions. It can be inferred from the numerical results that using DF relay nodes can extend the transmission distance and minimize BER performance of FSO system significantly compared with the direct transmission. Moreover, the selection of APD's gain values is essential to minimize the system's error rate performance. Therefore, the system could achieve the minimal BER by selecting an optimal average APD gain value appropriately. Moreover, the optimal average gain values of APD significantly depend on various conditions, such as the bit rate, total transmitted power, and the number of relay nodes.

2025, Journal of Optical Communications and Networking

2025

The wavelength division multiplexing (WDM) optical fiber system is an important enabling technology to satisfy the requirements of bandwidth of today's information age. The main objective of this research project is to develop novel devices with the potential applications in WDM systems. In particular, novel semiconductor fiber ring lasers based on a recently introduced linear optical amplifier (LOA) and all-optical signal processing devices based on an entirely new type of highly nonlinear fiber as well as devices based on injection-locking in Fabry Pérot laser diodes are investigated. We proposed and demonstrated a simple configuration of a widely tunable single wavelength semiconductor fiber ring laser and a multiwavelength semiconductor fiber ring laser based on a linear optical amplifier (LOA). In an LOA, a vertical-cavity surface-emitting laser is integrated, perpendicularly, along the entire length of the amplifier, serves as a ballast to provide a constant gain to the amplifier and helps to clamp the gain competition in a laser cavity. In case of a single wavelength laser, ultrawide continuous wavelength tuning range of over 90 nm was achieved using a scanning Fabry Pérot filter. In addition a stable multiwavelength semiconductor fiber ring laser was also realized using F-P etalon. Thirty eight lasing lines were obtained with a fixed channel spacing of 0.8 nm, which is defined by the free-spectral range of the F-P etalon. Power stability of less than 0.15 dB during a 3-hour test for a single channel of the multiwavelength laser demonstrated the stability of this laser. A gain clamped SOA scheme is also realized using optical feedback. Using this scheme a stable multiwavelength semiconductor fiber laser was demonstrated. support during all these years. Finally, I greatly appreciate the Hong Kong Polytechnic University for awarding the International postgraduate scholarship and the Asahi Glass Corporation Ltd., Japan for providing the bismuth-based highly nonlinear fibers.

2025, Journal of Optical Communications

Sigma Delta Radio over Fiber (S-DRoF) systems are looked upon as an enabling technology due to their advantages that comes due to combination of analog and digital radio over fiber (RoF) systems. In this paper, we have proposed and experimentally demonstrated a Multi-stAge-noise-SHaping (MASH) based Sigma Delta Modulated RoF system targeting 5G C-RAN (cloud/centralized radio access network) fronthaul applications. The evaluation has been done for LTE 20 MHz signal having 256 quadrature amplitude modulation with a carrier frequency of 3.5 GHz up to 5 Km of Standard Single Mode Fiber (SSMF). Furthermore, a comprehensive analysis of the design is explained followed by the experimental setup. The performance is reported in terms of error vector magnitude (EVM) and adjacent channel leakage ratio. It is concluded that S-DRoF substantiates the desired range of the 5G C-RAN fronthaul networks.

2025, Optics Express

Random bit generators (RBGs) constitute an important tool in cryptography, stochastic simulations and secure communications. The later in particular has some difficult requirements: high generation rate of unpredictable bit strings and secure key-exchange protocols over public channels. Deterministic algorithms generate pseudo-random number sequences at high rates, however, their unpredictability is limited by the very nature of their deterministic origin. Recently, physical RBGs based on chaotic semiconductor lasers were shown to exceed Gbit/s rates. Whether secure synchronization of two high rate physical RBGs is possible remains an open question. Here we propose a method, whereby two fast RBGs based on mutually coupled chaotic lasers, are synchronized. Using information theoretic analysis we demonstrate security against a powerful computational eavesdropper, capable of noiseless amplification, where all parameters are publicly known. The method is also extended to secure synchronization of a small network of three RBGs.

2025, Journal of the Optical Society of America B

2025

Zasadniczym problemem podczas wdrażania nowych systemów radiowych jest zagadnienie kompatybilności elektromagnetycznej z innymi systemami. Prace w tym zakresie rozpoczynają się w momencie ukończenia standaryzacji systemu i trwają często wiele lat (z powodu różnorodności systemów występujących w różnych krajach oraz czasochłonnych i kosztownych pomiarów). Wielokrotnie nowe systemy nie są wprowadzane w pasmach współużytkowanych z innymi pracującymi systemami radiowymi tylko dlatego, że nie są znane kryteria kompatybilności międzysystemowej, a ze względu na bezpieczeństwo nie można dopuścić do ewentualnych zakłóceń. Określenie zatem kryteriów kompatybilności jest niezwykle istotne, gdyż nie tylko nie dopuszcza do wzajemnych zakłóceń, ale również umożliwia efektywne wykorzystanie widma radiowego, na które zapotrzebowanie jest ogromne, podczas gdy jego zasoby pozostają niezmienne. Jest to zadanie ważne dla każdego kraju. Wiele jest bowiem systemów narodowych, dla których wykorzystanie ba...

2025, Microwave and Optical Technology Letters

An underwater optical link is proposed for communication between sensors on a swimmer during training. Tests in still-pool water, still-spa water, and bubbles-spa water demonstrated the attenuation of the signal. The system uses a light emitting device (LED) (520 nm) and optical detector and is operating at 520 nm. The attenuation constant was found to increase from 0.09 to 2.9 m À1 when the spa jets were turned on.

2025

In this paper, we present a new code design for the Optical Code Division Multiple Access (OCDMA) system based on the Jacobi function. One of the major factors limiting the performance of OCDMA systems is known as Multiple Access Interference (MAI). A good code design provides a minimum cross-correlation, maximum number of users with minimum code length, and implementation flexibility to remove the MAI effectively. The use of finite field arithmetic’s in the construction of our proposed code yield a zero cross-correlation (ZCC) which is the least desired value. Theoretical analysis and simulation results show that the proposed code outperforms the previously reported codes with zero maximum cross-correlation. Thus, the Multiple Access Interference (MAI) and Phase-Induced intensity noise (PIIN) effects are eliminated, improving the system’s performance. The system can accommodate more simultaneous users than other codes at a standard acceptable bit error rate value (≤ 10). Furthermor...

2025, SPIE Proceedings

Free space optical (FSO) communication has been a subject of interest for researcher and the corporate world since a few decades ago. This has been motivated by the huge benefits associated with this technology. Meanwhile, the generation and all optical up conversion of millimeter wave (mmw) for propagation in a FSO channel has been an important research direction. In this article, a single side band tone mmw generated by the optical carrier suppression (OCS) method has been modulated by modified duo-binary return to zero (MDRZ) and polarization shift keying (PolSK) modulated baseband data. The resulting optical signal was propagated in a FSO cannel subjected to combined weather and atmospheric turbulence induced fading. Later on, a comparative analysis was carried out between hybrid OCS/MDRZ and OCS/PolSK mmw signals propagated over free space. Using the performance metrics such as the bit error rate, quality (Q) factor and the received power among others, the simulation results indicated that hybrid OCS/MDRZ performs better than hybrid OCS/PolSK.

2025

We propose and experimentally demonstrate a fiber-wireless transmission system for optimized delivery of 60-GHz radio frequency (RF) signals through picocell mobile backhaul connections. We identify advantages of 60-GHz links for utilization in short-range mobile backhaul through feasibility analysis and comparison with an alternative E-band (60-90 GHz) technology. The 60-GHz fiber-wireless-fiber setup is then introduced: two spans of up to 20 km of optical fiber are deployed and bridged by up to 4 m of wireless distance. The 60-GHz radio-over-fiber technology is utilized in the first span of fiber transmission. The system is simplified and tailored for delivery of on-off keying data signals by employing a single module for lightwave generation and modulation combined with a simplified RF downconversion technique by envelope detection. Data signals of 1.25 Gb/s are transmitted, and a bit-error-rate performance below the 7% overhead forward-errorcorrection limit is achieved for a range of potential fiber deployment scenarios. A spurious free dynamic range of 73 dB-Hz 2=3 is attained for a frequency-doubling photonic RF upconversion technique. The power budget margin that is required to extend the wireless transmission distance from 4 m to a few hundred meters has been taken into account in the setup design, and the techniques to extend the wireless distance are analyzed.

2025

In this paper, we report on a detailed analysis and performance comparison work between 60 GHz radio-over-fiber systems based on a DFB laser and a C-band VCSEL. Coherent photonic up-conversion method is applied for the 60 GHz millimeter-wave signal generation. The generated signals are evaluated by means of phase noise and bit error rate for different transmission scenarios. The results show a positive potential to adopt both DFB lasers and VCSELs for the next generation 60 GHz hybrid fiber-wireless access networks.

2025, Optics Express

In this paper the on-the-field performance of a WDM-PON optical access providing quintuple-play services using orthogonal frequency division multiplexing (OFDM) modulation is evaluated in a real fiber-tothe-home (FTTH) network deployed by Towercom operator in Bratislava (Slovakia). A bundle of quintuple-play services comprising full-standard OFDM-based signals (LTE, WiMAX, UWB and DVB-T) and an ad-hoc OFDM-GbE signal is transmitted in coexistence per single user. Both downstream and upstream transmission performances are evaluated in different on-the-field long-reach optical link distance configurations. Four wavelength multi-user transmission of quintuple-play OFDM services is demonstrated exceeding 60.8 km reach in standard single mode fiber.

2025, 37th European Conference and Exposition on Optical Communications

Hybrid fiber-wireless transmission of 2-Gbps signals in 60-GHz band over a composite channel (10-km SMF/1-km MMF/6.5-m wireless) is experimentally demonstrated for gigabit inbuilding wireless access using simple direct modulation, optical... more

2025, Optics Express

We demonstrate that, by jointly optimizing video coding and radio-over-fibre transmission, we extend the reach of 60-GHz wireless distribution of high-quality high-definition video satisfying low complexity and low delay constraints,... more

2025, Journal of Lightwave Technology

This paper proposes and demonstrates experimentally the application of optical polarization-multiplexed radioover-fiber wireless backhauling of fully standard 3GPP carrieraggregated multiple-input multiple-output (MIMO) signals. The experimental work demonstrates successful long-reach optical transmission of 3GPP carrier-aggregated LTE-Advanced (LTE-A) signals using 2×2 MIMO spatial diversity. The suitability of MIMO provision using radio-over-fiber optical links is demonstrated over different E-UTRA frequency division duplex frequency bands. The performance of electrical carrier aggregation is evaluated in different configurations comprising one, three and five LTE-A component carriers of 10 and 20 MHz bandwidth each. The experimental results demonstrate successful 2×2 MIMO radioover-fiber polarization-multiplexed transmission of five LTE-A carriers over 25 km, three LTE-A carriers over 75 km and an LTE-A carrier over 100 km of standard single mode fiber to provide pervasive MIMO wireless service to a large number of users.

2025, IEEE Photonics Technology Letters

2025, Optical Fiber Communication Conference/National Fiber Optic Engineers Conference 2013

Cognitive networks are a promising solution for the control of heterogeneous optical networks. We review their fundamentals as well as a number of applications developed in the framework of the EU FP7 CHRON project.

2025, Journal of Optical Communications and Networking

The use of cognition is a promising element for the control of heterogeneous optical networks. Not only are cognitive networks able to sense current network conditions and act according to them, but they also take into account the knowledge acquired through past experiences; that is, they include learning with the aim of improving performance. In this paper, we review the fundamentals of cognitive networks and focus on their application to the optical networking area. In particular, a number of cognitive network architectures proposed so far, as well as their associated supporting technologies, are reviewed. Moreover, several applications, mainly developed in the framework of the EU FP7 Cognitive Heterogeneous Reconfigurable Optical Network (CHRON) project, are also described.

2025, Photonic Network Communications

In this article, a new dynamic bandwidth allocation algorithm for the upstream channel of Ethernet Passive Optical Networks, called DySLa, is proposed not only to provide service differentiation but also to offer subscriber differentiation. In contrast to previous methods in which the performance of each class of service is not insured, DySLa is continuously evaluating the mean packet delay and guarantees that the highest priority services fulfil the packet delay requirements in the access network for every type of client. Simulation results show that DySLa can maintain both the mean packet delay and packet loss ratio below the maximum upper bounds permitted for the most sensitive services of every class of customer. Moreover, DySLa outperforms other dynamic bandwidth allocation algorithms which provide service and client differentiation and it makes a fairer bandwidth distribution than those methods. Ethernet passive optical networks • Dynamic bandwidth allocation algorithms • Quality of service • Service level agreement • Class of service • Service and customer differentiation • Automatic weight adaptation

2025, Optics Express

We report on the experimental performance of a case-based reasoning technique to predict whether optical channels fulfill quality of transmission requirements, thus supporting impairment-aware networking. Validation is performed in a WDM... more

2025, Journal of Optical Communications

This paper considers the solutions to optical fibers and integrated optical dielectric waveguides. The unbounded medium surrounding the waveguide is modeled by infinite elements with edge bases. The inhomogeneous part of the waveguide is discretized into a recently-developed edge finite elements. To match the infinite elements with adjacent finite elements, compatible interpolation functions are proposed for the infinite elements. In consequence, the boundary conditions between finite and infinite elements are exactly satisfied. Also, the formulation in this paper is presented such that any decay function in the radial direction may be employed. However, explicit representations for the infinite element matrices are given for the case of an inverse power decay function. Other functions will be investigated in the future work. The solutions to the final system of equations provide the dispersion characteristics of the optical waveguide. A computer program and an automatic mesh generator were written and shown to be valid by comparing the solutions with other published data.

2025, International Journal of Engineering & Technology

This paper presents a triangular-lattice photonic crystal fiber for broadband dispersion compensation. The finite element method with perfectly matched absorbing layers boundary condition is used to investigate the guiding properties. The designed dispersion compensating fiber shows that it is possible to obtain a larger negative dispersion coefficient of ?360 ps/(nm.km) at 1.55 ?m, better dispersion slope compensation, better compensation ratio in the entire telecommunication (1460-1640 nm) band by using a modest number of design parameters and very simple cladding design.