Expansion and phase correlation of a wavelength tunable gain-switched optical frequency comb

A novel scheme for the expansion and phase correlation of a wavelength tunable gain-switched optical frequency comb (OFC) is presented. This method entails firstly combining two gain-switched OFCs and expanding them using a phase modulator. Subsequently, the phase correlation between all the comb lines is induced through four-wave mixing (FWM) in a semiconductor optical amplifier (SOA). In this article, the generation of 42 highly correlated comb lines separated by 6.25 GHz, with an optical carrier to noise ratio (OCNR) of more than 50 dB, is experimentally demonstrated. In addition, the wavelength tunability of the scheme, over 30 nm within the C band, is shown. Finally, the degree of phase correlation between comb lines is verified through RF beat tone linewidth measurements. The results show a five orders of magnitude reduction in the beat tone linewidth, due to FWM in an SOA

Reconfigurable multi-carrier transmitters and their application in next generation optical networks

With the advent of new series of Internet services and applications, future networks will have to go beyond basic Internet connectivity and encompass diverse services including connected sensors, smart devices, vehicles, and homes. Today’s telecommunication systems are static, with pre-provisioned links requiring an expensive and time-consuming reconfiguration process. Hence, future networks need to be flexible and programmable, allowing for resources to be directed, where the demand exists, thus improving network efficiency. A cost-effective solution is to utilise the legacy fibre infrastructure more efficiently, by reducing the size of the guard bands and allowing closer optical carrier spacing, thereby increasing the overall spectral efficiency. However, such a scheme imposes stringent transmitter requirements such as frequency stability, which would not be met with the incumbent laser-array based transmitters. An attractive alternative would be to employ an optical frequency comb (OFC), which generates multiple phase correlated carriers with precise frequency separation. The reconfigurability of such a multi-carrier transmitter would enable tuning of channel spacing, number of carriers and emission wavelengths, according to the dynamic network demands. This research thesis presents the work carried out, in the physical layer, towards realising reconfigurability of an optical multi-carrier transmitter system. The work focuses on an externally injected gain-switched laser-based OFC (EI-GSL), which is a particular type of multi-carrier source. Apart from the detailed characterisation of GSL OFCs, advances to the state of the art are achieved via comb expansion, investigating new demultiplexing methods and system implementations. Firstly, two novel broadband GS-OFC generation techniques are proposed and experimentally demonstrated. Subsequently, two flexible and compact demultiplexing solutions, based on micro-ring resonators and laser based active demultiplexers are investigated. Finally, the application of a reconfigurable multi-carrier transmitter, employed in access and data centre networks, as well as analog-radio over fibre (A-RoF) distribution systems, is experimentally demonstrated

Characterisation of optimum devices and parameters for enhanced optical frequency comb generation

The Internet has become an irreplaceable aspect of our daily life. It is used every day by billions of people around the world for various functions such as business, study, and entertainment. Hence, an unabated rise in the demand for higher and faster data traffic has been experienced through the last few decades. This demand for bandwidth is further fuelled by the introduction of bandwidth intensive applications such as ultra-high-definition video streaming, real time online gaming and cloud services making the realization of higher capacity and performance optical networks a necessity. Today’s telecommunication systems are static, with pre-provisioned links requiring an expensive and time-consuming reconfiguration process. The state-of-the-art approach (wavelength division multiplexing - WDM), entailing multiple lasers emitting differing wavelengths (each modulated) multiplexed together (on a 50 GHz grid), cannot meet the growing demands. Hence, future networks need to be flexible and programmable, allowing for resources to be directed, where the demand exists, thus improving network efficiency. A cost-effective solution is to utilise the legacy fibre infrastructure more efficiently by reducing the size of the guard bands and allowing closer optical carrier spacing, thereby increasing the overall spectral efficiency. However, such a scheme imposes a stringent transmitter requirement in terms of wavelength stability, noise properties and cost-efficiency, which would not be met with the incumbent laser-array based transmitters. An attractive alternative would be to employ an optical frequency comb (OFC), which generates multiple phase-correlated optical carriers with a precise frequency separation. The reconfigurability of such a multi-carrier transmitter would enable tuning of channel spacing, number of carriers and emission wavelengths, according to the dynamic network demands. This thesis focusses on the externally injected gain-switched laser-based OFC (GSL-OFC) technique. Advances to the state of the art are achieved via a detailed static and dynamic characterisation of lasers, which is then used for enhancing the comb generation process. Specifically, initial efforts are devoted to the use of different laser structures for OFC generation. This aspect is then furthered by incorporating the concept of photonic integration to reduce the cost, power consumption and footprint of the multi-carrier transmitter. Self and externally seeded photonic integrated circuits are used to generate combs that are then fully characterized to verify their employability in optical networks

VCSEL-based optical frequency comb generation, expansion and optimization: an experimental study

Esta tesis contiene artículos de investigación en anexoLas fuentes ópticas multimodo o peines en frecuencia (Optical Frequency Comb o OFC) han sido y son objeto de investigación en los últimos años dado que ofrecen numerosas posibilidades en diferentes campos como espectroscopía, comunicaciones ópticas, generación de terahercios, generación de señales arbitrarias ópticas, metrología o generación óptica de señales de radiofrecuencia. Los OFC son sistemas típicamente basados en equipos de sobremesa y componentes a medida, obteniendo sistemas robustos y señales de alta calidad pero difíciles de implementar y reproducir al mismo tiempo. Algunas de las aplicaciones de los OFCs tienen como elementos clave la eficiencia en tamaño, coste y consumo, de manera que es importante obtener combs con capacidades más moderadas pero que, a su vez, sean sistemas más flexibles, compactos y fáciles de implementar. Para ello, centramos nuestra atención en sistemas OFCs realizados con componentes comerciales que sean útiles para aplicaciones como generación de THz o espectroscopía. Para mantener estos objetivos, hemos elegido la generación de combs directa en diodos láser (laser diodes o LDs), dado que el OFC es creado en el interior de la cavidad láser sin necesidad de añadir componentes extra ni aumentar excesivamente la potencia necesaria por el sistema. Entre los diodos láser, los láseres de emisión superficial y cavidad vertical (Vertical-Cavity Surface-Emitting Lasers o VCSELs) son un tipo de láseres de diodo que han experimentado una gran evolución en los últimos años debido a las características que presentan: los VCSELs son dispositivos de bajo coste y pequeño tamaño, por lo que ofrecen la posibilidad de ser modulados a altas frecuencias con muy poco consumo de potencia. En este trabajo se estudiará el uso de láseres VCSEL (1550nm 10Gbps VCSELs fabricados por Vertilas GmbH) como elemento base de los OFCs utilizando una técnica de modulación no lineal conocida como Gain Switching (GS). Gracias a la modulación GS, el comb generado hereda el ruido del equipo usado para la modulación, obteniendo así alta correlación de fase entre sus modos. Con el dispositivo VCSEL bajo GS se ha obtenido un comb de hasta 135GHz de ancho en los 20dB superiores del espectro, llamado VCSEL-OFC. Los resultados presentados en esta Tesis demuestran que el uso de VCSELs permite la generación de combs más anchos y planos que con otras tecnologías y record en bajo consumo de energía. El comportamiento del VCSEL bajo GS se comparará con un sistema similar usando otro tipo de fuente láser que ha sido usado con buenos resultados anteriormente, un láser Discrete Mode, también bajo régimen GS. Sin embargo, el VCSEL-OFC sigue limitando su aplicación en algunos campos de nuestro interés como síntesis de THz o espectroscopía dado que necesitan combs más anchos. Esto fundamentó otro de los aspectos clave de este trabajo: la expansión de los combs, usando el VCSEL-OFC como semilla. Tres técnicas para expandir el VCSEL-OFC han sido implementadas, basándonos en fibras altamente no lineales (Highly Nonlinear Fibers, HNLF), lazos ópticos no lineales (Nonlinear Optical Loop Mirrors, NOLM) y moduladores Electro- Ópticos (EO). Con estos sistemas hemos expandido el comb resultante un factor 3, obteniendo combs de alrededor de 450GHz y manteniendo alta correlación entre modos. Posteriormente, dos de estas etapas de expansión, EO y HNLF, han sido implementadas en cascada para aunar sus efectos y se ha conseguido un comb de 1THz de ancho a 20dB, según nuestro conocimiento, el comb más ancho conseguido usando fuentes VCSELs y tecnologías disponibles comercialmente. Este comb es extraordinariamente ancho pero, sin embargo, necesita ser estudiado con más detalle para mejorar otras de sus características como la igualdad de potencia entre los modos considerados (flatness) o el rango dinámico. Por ello, para profundizar en el conocimiento del VCSEL como fuente para generar combs y así optimizar el VCSEL-OFC y todas sus expansiones implementadas, se ha realizado un estudio más profundo de dicho comb en relación a sus componentes de polarización. Los VCSELs típicamente se consideran fuentes monomodo pero tienen un segundo modo con polarización linear y ortogonal. Este modo es residual y se reduce su efecto durante la fabricación de la cavidad pero hemos comprobado que genera un comb residual, con menor potencia y este comb juega un papel fundamental si se equilibraran las potencias de ambos modos de polarización. Además, el uso de GS para la generación del comb hace que tanto los modos del comb principal como de este comb residual tienen alta correlación de fase. Para equilibrar las potencias de ambos modos de polarización, hemos incluido en nuestros experimentos la técnica de inyección (Optical Injection Locking, OIL) en la que una luz externa se inyecta en el láser para mejorar la señal a la salida. Jugando con la polarización de la señal inyectada, hemos conseguido equilibrar los combs correspondientes a ambos estados de polarización y también suprimir uno de ellos manteniendo únicamente el otro. En conclusión, un tipo de diodo laser de emisión vertical, VCSEL, ha sido evaluado para generación de peines ópticos multifrecuenciales. Para ello, se ha estudiado su comportamiento bajo GS, optimizando el ancho del comb generado. Posteriormente, se han implementado distintas técnicas para expandir y optimizar dichos combs. Los resultados han sido significativos, teniendo en cuenta el ancho del comb con respecto a la potencia necesaria y el coste y complejidad de los sistemas. Los combs basados en VCSELs prometen ser dispositivos a tener en cuenta para implementaciones de combs versátiles y compactos de bajo coste y bajo consumo de energía.Optical Frequency Combs (OFCs) are versatile systems and therefore many researchers have been interested in them during the last years as they open possibilities in a large variety of fields like spectroscopy, optical communications, THz generation, optical arbitrary waveform generation, metrology, or microwave photonic. OFCs systems are typically based on bench top lasers sources, often built with tailored components which make them robust and powerful but complex and difficult to reproduce at the same time. Some of the fields of application of OFCs do not need that bespoke systems but, on the contrary, more straightforward, flexible and compact systems are needed for applications aiming for size, cost and energy efficient set- ups. These features can be further enhanced by using only Off the Shelf components obtaining suitable combs for applications like THz generation or spectroscopy. This is the approach in which our attention is centered. Trying to maintain this idea as the horizon of this work, direct OFC generation in laser diodes (LDs), in which the comb is generated inside the LD cavity, has been the focus of the present work. With such an approach, the component count is not increased and the energy consumption remains low. Among the numerous laser diode technologies available, Vertical-Cavity Surface-Emitting Lasers (VCSELs) are cost effective devices with small size. On top of this, they offer high speed capabilities with a very small amount of injected power. These special features are the reason why, in this work, VCSELs (1550nm 10Gbps VCSELs from Vertilas GmbH) are analyzed as the main source to be used for comb generation based on a well stablished nonlinear radio-frequency modulation technique: Gain Switching (GS). Thanks to the GS regime, an optical comb is generated with a very special feature: its modes inherit the stability of the radio-frequency source used for the laser modulation. Hence, the resulting comb exhibits a very high correlation between its modes. With this, a comb of 135GHz in the 20dB span is generated (VCSEL-OFC). The results presented in this Thesis demonstrate that the use of high performance VCSELs permits the generation of very flat optical combs with enhanced optical span and record energy efficiency. The VCSEL performance to generate OFCs is compared in this study to a different type of LD source: Discrete Mode (DM) laser under GS. The results showed that VCSEL-OFC is significantly broader than the comb obtained with other LD technologies under GS. However, the overall optical span that VCSEL based combs provide still needs to be increased to match the majority of the applications targeted. Especially for THz generation or dual-comb spectroscopy, two of the applications that launched our interest in LD combs, this is an important issue. Finding a way to overcome this limitation was the beginning of another of the key studies presented here. The expansion of the VCSEL-OFC, the seed comb. For this purpose, three different expansion techniques were implemented to increment the total span: Highly Nonlinear Fibers (HNLF), Nonlinear Optical Loop Mirrors (NOLM) and Electro-Optic (EO) Modulators. The resulting combs are 3 times broader than the seed VCSEL-OFC, thus combs around 450GHz in the 20dB span have been achieved maintaining high correlation between the comb lines. Subsequently, two of these expansion techniques, the EO and HNLF, have been cascaded to join their expansion effects and a comb of 1THz in the 20dB span has been generated, which is, to our knowledge, the broadest comb achieved using LDs and off the Shelf components. Even when this comb is remarkably broad some other features should be improved: the flatness and the dynamic range. Then, more efforts should be done to study the nature of the VCSEL-OFC. In order to deepen into the VCSEL knowledge for comb generation, to optimize both the VCSEL-OFC and the expansion stages implemented, polarization dynamics studies on the VCSEL in CW emission and the VCSEL under GS were performed. VCSELs are considered monomode laser sources but they present a residual orthogonally polarized mode whose emission is suppressed during fabrication. However, we observed that this residual mode also generates a comb that could play an important role. Using GS for the generation provides high phase correlation among the teeth in the main comb and also in this orthogonally-polarized residual comb. Trying to achieve a balance between both polarization components, Optical Injection Locking (OIL) was implemented. Playing with the injected state of polarization, the combs correspondent to the two states of polarization in VSCELs were balanced and the resulting comb was slightly broader and flatter. Also, one of the optical combs could be enhanced suppressing the other state of polarization with OIL. To conclude, Vertical-Cavity Surface-Emitting Lasers (VCSELs) have been evaluated for optical frequency comb generation. For this, their behavior under GS has been studied, focusing on the optimization of the optical span. Subsequently, different techniques for comb expansion and optimization have been implemented obtaining remarkable results, taking into account the optical span, the energy needs and the complexity of the set-ups. For all this, VCSELs are devices to be used to build versatile, compact, low cost and low energy consumption comb generation systems.Programa Oficial de Doctorado en Ingeniería Eléctrica, Electrónica y AutomáticaPresidente: Víctor Torres Company.- Secretario: Ana Quirce Teja.- Vocal: Borja Vidal Rodrígue

Optical code-division multiple access system and optical signal processing

This thesis presents our recent researches on the development of coding devices, the investigation of security and the design of systems in the optical cod-division multiple access (OCDMA) systems. Besides, the techniques of nonlinear signal processing used in the OCDMA systems fire our imagination, thus some researches on all-optical signal processing are carried out and also summarized in this thesis. Two fiber Bragg grating (FBG) based coding devices are proposed. The first coding device is a superstructured FBG (SSFBG) using ±π/2-phase shifts instead of conventional 0/π-phase shifts. The ±π/2-phase-shifted SSFBG en/decoders can not only conceal optical codes well in the encoded signals but also realize the reutilization of available codes by hybrid use with conventional 0/π-phase-shifted SSFBG en/decoders. The second FBG based coding device is synthesized by layer-peeling method, which can be used for simultaneous optical code recognition and chromatic dispersion compensation. Then, two eavesdropping schemes, one-bit delay interference detection and differential detection, are demonstrated to reveal the security vulnerability of differential phase-shift keying (DPSK) and code-shift keying (CSK) OCDMA systems. To address the security issue as well as increase the transmission capacity, an orthogonal modulation format based on DPSK and CSK is introduced into the OCDMA systems. A 2 bit/symbol 10 Gsymbol/s transmission system using the orthogonal modulation format is achieved. The security of the system can be partially guaranteed. Furthermore, a fully-asynchronous gigabit-symmetric OCDMA passive optical network (PON) is proposed, in which a self-clocked time gate is employed for signal regeneration. A remodulation scheme is used in the PON, which let downstream and upstream share the same optical carrier, allowing optical network units source-free. An error-free 4-user 10 Gbit/s/user duplex transmission over 50 km distance is reazlied. A versatile waveform generation scheme is then studied. A theoretical model is established and a waveform prediction algorithm is summarized. In the demonstration, various waveforms are generated including short pulse, trapezoidal, triangular and sawtooth waveforms and doublet pulse. ii In addition, an all-optical simultaneous half-addition and half-subtraction scheme is achieved at an operating rate of 10 GHz by using only two semiconductor optical amplifiers (SOA) without any assist light. Lastly, two modulation format conversion schemes are demonstrated. The first conversion is from NRZ-OOK to PSK-Manchester coding format using a SOA based Mach-Zehnder interferometer. The second conversion is from RZ-DQPSK to RZ-OOK by employing a supercontinuum based optical thresholder

Lasers à blocage de modes à base de boîtes et bâtonnets quantiques pour les peignes de fréquences optiques

Optical frequency combs, generating tens of equally spaced optical carriers from a single laser source, are very attractive for next-generation wavelength division multiplexing (WDM) communication systems. This PhD thesis presents a study on the optical frequency combs generated by mode-locked laser diodes based on low-dimensional semiconductor nanostructures. In this work, the mode-locking performances of single-section Fabry-Pérot lasers based on different material systems are compared on the basis of the optical spectrum width, the timing jitter and pulse generation capabilities. Then, noticing that InAs quantum dashes grown on InP exhibit on average better characteristics than other examined materials, their unique properties in terms of comb stability and pulse chirp are studied in more detail. Laser chirp, in particular, is first investigated by frequency resolved optical gating (FROG) characterizations. Then, chromatic dispersion of the laser material is assessed in order to verify whether it can account for the large chirp values measured by FROG. For that, a high sensitivity optical frequency-domain reflectometry setup is used and its measurement capabilities are extensively studied and validated. Finally, the combs generated by quantum dash mode-locked lasers are successfully employed for high data rate transmissions using direct-detection optical orthogonal frequency division multiplexing. Terabit per second capacities, as well as the low cost of this system architecture, appear to be particularly promising for future datacom applicationsLes peignes de longueurs d'onde, produisant des dizaines de porteuses optiques régulièrement espacées à partir d'une seule source laser, présentent un grand intérêt pour les systèmes de communication à haut débit. Ce travail de thèse porte sur les peignes générés par les diodes laser à blocage de modes basées sur des nanostructures semi-conductrices à basse dimensionnalité. Dans cette étude, les performances en verrouillage de modes de lasers Fabry-Pérot mono-section basés sur différents systèmes de matériaux sont comparées sur la base de la largeur du spectre optique d'émission et de la capacité à produire des impulsions courtes à faible gigue temporelle. En remarquant que les lasers à base de bâtonnets quantiques InAs sur InP présentent de meilleures caractéristiques par rapport aux autres matériaux examinés, leurs propriétés spécifiques en termes de stabilité des peignes de fréquences optiques et de chirp des impulsions sont étudiées plus en détail. Le chirp est d'abord étudié par la technique FROG (frequency-resolved optical gating). Ensuite, la dispersion chromatique du matériau laser est évaluée afin de vérifier si elle peut expliquer les grandes valeurs de chirp mesurées par FROG. Pour cela la technique de réflectométrie optique dans le domaine fréquentiel est utilisée et ses capacités uniques de mesure ont été étudiées et validées. Enfin, ces lasers sont employés avec succès pour les transmissions haut débit à l'aide de la technique de modulation optique OFDM (orthogonal frequency-division multiplexing) en détection directe. Débits de l'ordre du térabit par seconde, ainsi que le faible coût de l’architecture du système, sont très prometteurs pour les data center

Investigation of performance issues affecting optical circuit and packet switched WDM networks

Optical switching represents the next step in the evolution of optical networks. This thesis describes work that was carried out to examine performance issues which can occur in two distinct varieties of optical switching networks. Slow optical switching in which lightpaths are requested, provisioned and torn down when no longer required is known as optical circuit switching (OCS). Services enabled by OCS include wavelength routing, dynamic bandwidth allocation and protection switching. With network elements such as reconfigurable optical add/drop multiplexers (ROADMs) and optical cross connects (OXCs) now being deployed along with the generalized multiprotocol label switching (GMPLS) control plane this represents the current state of the art in commercial networks. These networks often employ erbium doped fiber amplifiers (EDFAs) to boost the optical signal to noise ratio of the WDM channels and as channel configurations change, wavelength dependent gain variations in the EDFAs can lead to channel power divergence that can result in significant performance degradation. This issue is examined in detail using a reconfigurable wavelength division multiplexed (WDM) network testbed and results show the severe impact that channel reconfiguration can have on transmission performance. Following the slow switching work the focus shifts to one of the key enabling technologies for fast optical switching, namely the tunable laser. Tunable lasers which can switch on the nanosecond timescale will be required in the transmitters and wavelength converters of optical packet switching networks. The switching times and frequency drifts, both of commercially available lasers, and of novel devices are investigated and performance issues which can arise due to this frequency drift are examined. An optical packet switching transmitter based on a novel label switching technique and employing one of the fast tunable lasers is designed and employed in a dual channel WDM packet switching system. In depth performance evaluations of this labelling scheme and packet switching system show the detrimental impact that wavelength drift can have on such systems

Terabit-Rate Transmission Using Optical Frequency Comb Sources

Energy-efficient Tbit/s optical interconnects are key elements for future communication systems. Three novel optical frequency comb sources are investigated, which have the potential of being integrated in chip-scale Tbit/s transmitters. Such frequency combs provide a large number of carriers. The equidistance of the comb lines helps to minimize spectral guard bands. For each type of comb source, coherent data transmission experiments show the potential for Tbit/s data transmission rates

Optical frequency comb source for next generation access networks

The exponential growth of converged telecommunication services and the increasing demands for video rich multimedia applications have triggered the vast development of optical access technology to resolve the capacity bottleneck at metropolitan-access aggregations. To further enhance overall performance, next generation optical access networks will require highly efficient wavelength division multiplexing (WDM) technology beyond the capability of current standard time division multiplexed (TDM) systems. The successful implementation of future-proof WDM access networks depends on advancements in high performance transmission schemes as well as economical and practical electronic/photonic devices. This thesis focuses on an investigation of the use of optical frequency comb sources, and spectrally efficient modulation formats, in high capacity WDM based optical access networks. A novel injected gain switched comb generation technique which deliver simplicity, reliability, and cost effectiveness has been proposed and verified through experimental work. In addition, a detailed characterization of the optical comb source has been undertaken with special attention on the phase noise property of the comb lines. The potential of the injected gain switched comb source is then demonstrated in a digital coherent receiver based long reach WDM access scenario, which intends to facilitate 10 - 40 Gbit/s data delivery per channel . Furthermore, an optical scalar transmission scheme enabling the direct detection of higher order modulation format signals has been proposed and experimentally investigated

Quantum Dash Multi-Wavelength Lasers for Next Generation High Capacity Multi-Gb/s Millimeter-Wave Radio-over-Fiber Wireless Communication Networks

The ever-increasing proliferation of mobile users and new technologies with different applications and features, and the demand for reliable high-speed high capacity, pervasive connectivity and low latency have initiated a roadmap for the next generation wireless networks, fifth generation (5G), which is set to revolutionize the existing wireless communications. 5G will use heterogeneous higher carrier frequencies from the plentifully available spectra in the higher microwave and millimeter-wave (MMW) bands, including licensed and unlicensed spectra, for achieving multi-Gb/s wireless connectivity and overcoming the existing wireless spectrum crunch in the sub-6 GHz bands, resulting from the tremendous growth of data-intensive technologies and applications. The use of MMW when complemented by multiple-input-multiple-output (MIMO) technology can significantly increase data capacity through spatial multiplexing, and improve coverage and system reliability through spatial diversity. However, high-frequency MMW signals are prone to extreme propagation path loss and are challenging to generate and process with conventional bandwidth-limiting electronics. In addition, the existing digitized fronthaul for centralized radio access network (C-RAN) architecture is considered inefficient for 5G and beyond. Thus, to fully exploit the promising MMW 5G new radio (NR) resource and to alleviate the electronics and fronthaul bottleneck, microwave photonics with analog radio-over-fiber (A-RoF) technology becomes instrumental for optically synthesizing and processing broadband RF MMW wireless signals over optical links. The generation and distribution of high-frequency MMW signals in the optical domain over A-RoF links facilitate the seamless integration of high-capacity, reliable and transparent optical networks with flexible, mobile and pervasive wireless networks, extending the reach and coverage of high-speed broadband MMW wireless communications. Consequently, this fiber-wireless integration not only overcomes the problem of high bandwidth requirements, transmission capacity and span limitation but also significantly reduces system complexity considering the deployment of ultra-dense small cells with large numbers of 5G remote radio units (RRUs) having massive MIMO antennas with beamforming capabilities connected to the baseband units (BBU) in a C-RAN environment through an optical fiber-based fronthaul network. Nevertheless, photonic generation of spectrally pure RF MMW signals either involves complex circuitry or suffers from frequency fluctuation and phase noise due to uncorrelated optical sources, which can degrade system performance. Thus simple highly integrated and cost-efficient low-noise optical sources are required for next-generation MMW RoF wireless transmission systems. More recently, well-designed quantum confined nanostructures such as semiconductor quantum dash/dot multi-wavelength lasers (QD-MWLs) have attracted more interest in the photonic generation of RF MMW signals due to their simple compact and integrated design with highly coherent and correlated optical signals having a very low phase and intensity noise attributed to the inherent properties of QD materials. The main theme of this thesis revolves around the experimental investigation of such nanostructures on the device and system level for applications in high-speed high-capacity broadband MMW RoF-based fronthaul and wireless access networks. Several photonic-aided high-capacity long-reach MMW RoF wireless transmission systems are proposed and experimentally demonstrated based on QD-MWLs with the remote distribution and photonic generation of broadband multi-Gb/s MMW wireless signals at 5G NR (FR2) in the K-band, Ka-band and V-band in simplex, full-duplex and MIMO configurations over 10 to 50 km optical fiber and subsequent wireless transmission and detection. The QD-MWLs-based photonic MMW RoF wireless transmission systems’ designs and experimental demonstrations could usher in a new era of ultra-high-speed broadband multi-Gb/s wireless communications at the MMW frequency bands for next-generation wireless networks. The QD-MWLs investigated in this thesis include a simple monolithically integrated and highly coherent low-noise single-section semiconductor InAs/InP QD buried heterostructure passively mode-locked (PML) laser-based optical coherent frequency comb (CFC) and a novel monolithic highly correlated low-noise semiconductor InAs/InP buried heterostructure common-cavity QD dual-wavelength distributed feedback laser (QD-DW-DFBL). The performance of each device is thoroughly characterized experimentally in terms of optical phase noise, relative intensity noise (RIN), timing jitter and RF phase noise exhibiting promising results. Based on these devices, different long-reach photonic MMW RoF wireless transmission systems, including simplex single-input-single-output (SISO) and multiple-input-multiple-output (MIMO) and bidirectional configurations, are proposed and experimentally demonstrated with real-time remote electrical RF synthesizer-free all-optical frequency up-conversion, wireless transmission and successful reception of wide-bandwidth multi-level quadrature amplitude modulated (M-QAM) RF MMW wireless signals having bit rates ranging from 4 Gb/s to 36 Gb/s over different hybrid fiber-wireless links comprising of standard single mode fiber (SSMF) and indoor wireless channel. The end-to-end links are thoroughly investigated in terms of error-vector-magnitude (EVM), bit-error-rat (BER), constellations and eye diagrams, realizing successful error-free transmission. Finally, novel high-capacity spectrally efficient MIMO and optical beamforming enabled photonic MMW RoF wireless transceivers design and methods based on QD-MWLs with wavelength division multiplexing (WDM) and space division multiplexing (SDM) are proposed and discussed. A proof-of-concept implementation of the proposed photonic MMW RoF wireless transmission system is also simulated in a simple WDM-based configuration with bidirectional 4×4 MIMO MMW carrier streams