A Review Paper on Evolution of Internet

Broadband presents cease customer’s excessive-velocity while affording provider the capability to offer price-added services to growth revenues. Because of the growth of the internet, there was super buildout of high-speed, inter-metropolis communications links that connect population centers and internet provider carriers (ISPs) factors of presence (PoPs) surrounding the sector. This construct out of the spine infrastructure or center network has passed off in the main thru optical shipping generation

LINEAR RING RESONATOR MODULATOR FOR MICROWAVE PHOTONIC LINKS

Modulators within Microwave photonic links (MPLs) encode Radio Frequency (RF) signal information to the optical domain for transmission in applications such as wireless access networks and antenna remoting exploiting advantages optical fiber offers over RF coaxial cables including bandwidth, loss, size, weight, and immunity to electromagnetic interference. A critical figure-of-merit in MPLs is spur-free-dynamic-range (SFDR) defining the range of RF signal power a MPL transmits without distortion. Current Mach-Zehnder Interference (MZI) modulators used in MPLs limit the SFDR because of the associated nonlinear sinusoidal transfer function. A rigorous theoretical method is developed followed by design, fabrication, and testing to investigate a linear ring resonator modulator (RRM) modulator for MPLs. The linear nature of the Lorentzian transfer function for the RRM is utilized over the sinusoidal transfer function within MZI modulators offering significant improvement in MPL SFDR. A novel bias voltage adjustment method is developed for practical implementations improving SFDR of 6 dB versus MZI at 500 MHz noise bandwidth. RRM is shown to be applicable for applications requiring high operational frequencies while in a limited operational bandwidth such as millimeter-wave wireless networks. To improve RRM SFDR in wide operational bandwidths a novel dual ring resonator modulator (DRRM) design is demonstrated. DRRM suppresses the third order intermodulation distortion in a frequency independent process removing SFDR limits of RRM

Systèmes hybrides opto/sans fil pour les réseaux multi-gigabits aux fréquences millimétriques

This thesis focuses on the radio-over-fiber (RoF) communication systems at millimeter frequencies in the frequency range 57-66 GHz and optical generation of a signal at millimeter-wave frequency band. The technique used is based on mode-locked laser diodes. The diodes employed in this work are in quantum dots (or quantum dashes) technology. In this thesis, several studies were conducted: the first relates the ability of integration these types of lasers in the RoF communication systems under direct or external modulation. The second study was devoted to propagation effects. An original technique was implemented to reduce the sensitivity to chromatic dispersion in an optical fiber. A study of the reduction of phase noise mode-locked lasers based on the observation of the reaction effect and against the external optical injection was presented.Ce travail de thèse porte sur les systèmes de communication radio-sur-fibre (RoF) aux fréquences millimétriques dans la gamme de fréquences 57-66 GHz et leur génération par voie optique. La technique utilisée repose sur l’emploi de diodes laser à verrouillage de modes à boites quantiques. Au cours de cette thèse, plusieurs études ont été effectuées : la première porte sur la capacité d’intégrer ces types des lasers dans des systèmes de communication RoF avec leurs performances sous modulation directe ou externe. La deuxième étude a été consacrée aux effets de la propagation de ces signaux dans des systèmes basés sur les lasers à blocage de modes. Une technique originale a été mise en place afin de réduire la sensibilité à la dispersion chromatique dans la fibre optique. Une étude de la réduction du bruit de phase des lasers à verrouillage de modes basée sur l’observation de l’effet de la contre réaction et l’injection optique externe a été également présentée

Systèmes hybrides opto/sans fil pour les réseaux multi-gigabits aux fréquences millimétriques

This thesis focuses on the radio-over-fiber (RoF) communication systems at millimeter frequencies in the frequency range 57-66 GHz and optical generation of a signal at millimeter-wave frequency band. The technique used is based on mode-locked laser diodes. The diodes employed in this work are in quantum dots (or quantum dashes) technology. In this thesis, several studies were conducted: the first relates the ability of integration these types of lasers in the RoF communication systems under direct or external modulation. The second study was devoted to propagation effects. An original technique was implemented to reduce the sensitivity to chromatic dispersion in an optical fiber. A study of the reduction of phase noise mode-locked lasers based on the observation of the reaction effect and against the external optical injection was presented.Ce travail de thèse porte sur les systèmes de communication radio-sur-fibre (RoF) aux fréquences millimétriques dans la gamme de fréquences 57-66 GHz et leur génération par voie optique. La technique utilisée repose sur l’emploi de diodes laser à verrouillage de modes à boites quantiques. Au cours de cette thèse, plusieurs études ont été effectuées : la première porte sur la capacité d’intégrer ces types des lasers dans des systèmes de communication RoF avec leurs performances sous modulation directe ou externe. La deuxième étude a été consacrée aux effets de la propagation de ces signaux dans des systèmes basés sur les lasers à blocage de modes. Une technique originale a été mise en place afin de réduire la sensibilité à la dispersion chromatique dans la fibre optique. Une étude de la réduction du bruit de phase des lasers à verrouillage de modes basée sur l’observation de l’effet de la contre réaction et l’injection optique externe a été également présentée

Investigation of wavelength tunable laser modules for use in future optically switched dense wavelength division multiplexed networks

This thesis investigates the use of fast wavelength tunable laser modules in future optically switched dense wavelength division multiplexed networks (DWDM). The worldwide demand for increasingly greater broadband access has thus far been satisfied by the use of DWDM networks, enabled by the development of the erbium doped amplifier. However as this demand continues to grow electronic switching at network nodes will become a limiting factor, creating a potential bandwidth mismatch between the fibre capacities and switching capacity. Optical switching has been proposed to overcome this electronic bottleneck and fully utilize the enormous bandwidth offered by fibre. Fast tunable lasers (TLs) are a key technology in this area, enabling fast wavelength switching. Experimental work involving the fast wavelength switching of sampled grating distributed Bragg reflector TL modules is presented. Spurious mode generation during wavelength tuning is shown to cause severe cross-channel interference on other data channels in a DWDM test bed. Bit error rate (BER) results demonstrate that a integrated semiconductor optical amplifier can greatly reduce system degradation caused by asynchronous switching of multiple TLs. This is achieved by optically blanking the laser output during channel transition for a period of 60 ns. Immediately after the blanking period a wavelength drift due to the TL module wavelength locking is found to cause cross channel interference and introduce an error floor >1 e-4 on the BER performance characteristic of an adjacent channel in a 12.5 GHz spaced DWDM network. This drift is characterised, using a selfheterodyne and a filter based approach – Error free performance is subsequently demonstrated by using an extended blanking period of 260 ns or by using subcarrier multiplexing transmission and phase selective demodulation before detection. A DWDM optical label switching system, utilizing 40 Gbit/s payload data with low data rate labels placed on a 40 GHz sub-carrier and using TL transmitters is presented. Channel performance is monitored on a static channel as a second data channel is tuned into an adjacent channel on a 100 GHz spaced grid. Error free performance is demonstrated only for the channel payload – Time resolved BER results in agreement with the TL wavelength drift are measured and demonstrate a detrimental influence of the drift on the sub-carrier label performance

High-Performance On-Chip Microwave Photonic Signal Processing Using Linear and Nonlinear Optics

Manipulating and processing radio-frequency (RF) signals using integrated photonic devices has recently emerged as a paradigm-shifting technology for future microwave applications. This emerging technique is referred to as integrated microwave photonics (IMWP) which enables the high-frequency processing and unprecedentedly wideband tunability in compact photonic circuits, with significantly enhanced stability and robustness. However, to find widespread applications, the performance of IMWP devices must meet or exceed the achievable performance of conventional electronic counterparts. The work presented in this thesis investigates high-performance IMWP signal processing from two aspects: the optimized IMWP processing schemes and the photonic integration. Firstly, we explore novel schemes to improve the performance of chip-based microwave photonic subsystems, such as RF delay lines and RF filters which are basic building blocks of RF systems. A phase amplification technique is demonstrated to achieve a Si3N4 chip-based RF time delay with a delay tuning speed at gigahertz level. A new scheme to achieve an all-optimized RF photonic notch filter is demonstrated, producing a record-high RF link performance and complete functionalities. To unlock the potential of RF signal processing, we investigate a new filter concept of pairing linear and nonlinear optics for a high-performance RF photonic filter. To reduce the footprint of the novel IMWP filter, the photonic integration of both the ring resonators and Brillouin-active circuits on the same photonic chip is achieved. To eliminate the use of integrated optical circulators for on-chip SBS, on-chip backward inter-modal stimulated Brillouin scattering is predicted and experimentally demonstrated in a Si-Chalcogenide hybrid integrated photonic platform. The study and demonstrations presented in this thesis make the first viable step towards high-performance IMWP signal processing for real-world RF applications