Radio over fibre distribution systems for ultra-wide band and millimetre wave applications

Short range wireless technology such as ultra-wideband (UWB) and 60 GHz millimetre wave (mm-wave) play a key role for wireless connectivity in indoor home, office environment or large enclosed public areas. UWB has been allocated at the frequency band 3.1-10.6 GHz with an emission power below -41.3 dBm. Mm-wave signals around 60 GHz have also attracted much attention to support high-speed data for short range wireless applications. The wide bandwidth and high allowable transmit power at 60 GHz enable multi-Gbps wireless transmission over typical indoor distances. Radio-over-fibre (RoF) systems are used to extend the propagation distance of both UWB and mm-wave signals over hundred of meters inside a building. UWB or mm-wave signals over fibre can be generated first at the central office before being distributed to the remote access points through optical fibre. In this work, we investigate two new techniques to generate and distribute UWB signals. These techniques are based on generating Gaussian pulse position modulation (PPM) using a gain switched laser (GSL). The simulation and experimental results have been carried out to show the suitability of employing gain switching in UWB over fibre systems (UWBoF) to develop a reliable, simple, and low cost technique for distributing UWB pulses. The second part of this work proposes two configurations for optical mm-wave generation and transmission of 3 Gbps downstream data based on GSL. We investigate the distribution of these two methods over fibre with wireless link, and demonstrate the system simplicity and cost efficiency for mm-wave over fibre systems. Both configurations are simulated to verify our obtained results and show system performance at higher bit rates. In the third part, we generate phase modulated mm-waves by using an external injection of a modulated light source into GSL. The performance of this system is experimentally investigated and simulated for different fiber links

All-Optical Logic Gates and Wavelength Conversion Via the Injection-Locking of a Fabry-Perot Semiconductor Laser

This work investigates the implementation of all-optical wavelength conversion and logic gates based on optical injection locking (OIL). All-optical inverting, NOR, and NAND gates are experimentally demonstrated using two distributed feedback (DFB) lasers, a multi-mode Fabry-Perot laser diode (MMFP-LD), and a optical band-pass filter (BPF). The DFB lasers are externally modulated to represent logic inputs into the cavity of the MMFP-LD slave laser. The master lasers\u27 wavelengths are aligned with the longitudinal modes of the MMFP-LD slave laser and their optical power is used to modulate the injection conditions in the slave laser. The optical BPF is used to select the longitudinal mode that is suppressed or transmitted given the logic state of the injecting master laser signals. When the input signal(s) is (are) in the on state, injection locking, and thus the suppression of the non-injected Fabry-Perot modes, is induced, yielding a dynamic system that can be used to implement photonic logic functions. Additionally, all-optical photonic processing is achieved using the cavity mode shift produced in the injected slave laser under external optical injection. The inverting logic case can also be used as a wavelength converter -- a key component in advanced wavelength-division multiplexing networks. The result of this experimental investigation is a more comprehensive understanding of the locking parameters concerning the injection of multiple lasers into a multi-mode cavity. Attention is placed on the turn-on/turn-off transition dynamics, along with the maximum achievable bit rates. The performance of optical logic computations and wavelength conversion has the potential for ultrafast operation, limited primarily by the photon decay rate in the slave laser

Improvements to Optical Communication Capabilities Achieved through the Optical Injection of Semiconductor Lasers

Optically injection locked lasers have shown significant improvement in the modulation capabilities of directly modulated lasers. This research creates a direct-modulated optical communications system to investigate the bit-rate distance improvements achievable using optically injected Fabry-Pérot laser diodes. The injection strength and detuning frequency of the injection signal was varied to determine their impact on the optical communication link\u27s characteristics. This research measured a 25 fold increase in bit-rate distance product using optical injection locking as compared to the injected laser\u27s free-running capability. A 57 fold increase was measured in the bit-rate distance product when signal power is considered in a power-penalty measurement. This increased performance is attributed to the injected signals tolerance to dispersion given its reduced linewidth and chirp. This work also investigates the suitability of optical injection for radio over fiber applications using the period-one dynamic of optical injection. The all-optically generated, widely tunable microwave subcarrier frequency, well above the 3-dB cutoff frequency of the laser\u27s packaging electronics, was modulated with the same baseband electronics. This optically carried, ultra-wide spread spectrum signal was transported over 50km of standard-single-mode fiber. After detection at a high-speed photo- detector and the baseband modulation component was removed, the resultant signal was found to be suitable for broadcasting with an antenna or added to a frequency division multiplexed channel

Distribuição de sinais OFDM e vídeo sobre fibra

Mestrado em Engenharia Electrónica e TelecomunicaçõesEste trabalho incide na transmissão de sinais de rádio e vídeo sobre fibra óptica, usando modulação analógica de amplitude, ou seja sistemas do tipo Radio over Fiber (RoF). Começamos por descrever alguns dos sinais de rádio e vídeo que podem beneficiar, em certas aplicações, do recurso a sistemas RoF. Prosseguimos com a transmissão de sinais OFDM, na banda das micro-ondas e ondas-milimétricas, de forma a concluir acerca das vantagens e desvantagens dos vários tipos de modulação óptica que podemos utilizar no transmissor. Também focamos a multiplicação de frequência óptica no sentido de identificar soluções para distribuição de sinais RF de alta frequência, a baixo custo. De seguida, dando sequência ao estudo da transmissão dos sinais OFDM, analisamos alguns dos cenários de transmissão de sinais WPAN de acordo com os standards ECMA-368 e ECMA-387. Finalmente, acabamos por estudar brevemente a distribuição de sinais de vídeo digital sobre fibra usando modulação externa.This work focuses on the transmission of radio and video signals over fiber using analog amplitude modulation, i.e. Radio over Fiber (RoF) systems. We begin by describing some of the radio and video signals that can benefit, in certain applications, of the use of RoF systems. Then, we will proceed to the transmission of OFDM signals, in the microwave and millimeter-wave frequency band, in order to assess the advantages and disadvantages of several types of optical modulation that we can use at the transmitter. We also study optical frequency multiplication in order to identify solutions to the low-cost distribution of high frequency signals. Then, following the transmission of OFDM signals, we analyzed some of the possible scenarios for distribution of WPAN signals according to the standards ECMA-368 and ECMA-387. Finally we briefly examine the distribution of digital video signals over fiber using external modulation