MEMS for Photonic Integrated Circuits

The field of microelectromechanical Systems (MEMS) for photonic integrated circuits (PICs) is reviewed. This field leverages mechanics at the nanometer to micrometer scale to improve existing components and introduce novel functionalities in PICs. This review covers the MEMS actuation principles and the mechanical tuning mechanisms for integrated photonics. The state of the art of MEMS tunable components in PICs is quantitatively reviewed and critically assessed with respect to suitability for large-scale integration in existing PIC technology platforms. MEMS provide a powerful approach to overcome current limitations in PIC technologies and to enable a new design dimension with a wide range of applications

Impact of in-band crosstalk in an optical network based on multi-degree CDC ROADMs

he most common optical networks nodes are known as reconfigurable optical add/drop multiplexers (ROADMs). The architecture and components of these nodes have evolved over the time to become more flexible and dynamic. Particularly, the wavelength add/drop structures of these nodes have become more complex and with new features such as colorless, directionless and contentionless (CDC). One of the main limitations of the optical networks physical layer, the in-band crosstalk, is mainly due to the imperfect isolation of the components inside these nodes. This crosstalk is enhanced, when an optical signal traverses a cascade of ROADM nodes. In this work, the impact of in-band crosstalk, optical filtering and amplified spontaneous emission (ASE) noise on the performance of an optical communication network based on a cascade of CDC ROADMs with coherent detection and the modulation format quadrature phase-shift keying with polarization-division multiplexing (PDM-QPSK) at 100-Gb/s is studied through Monte-Carlo simulation. Two architectures, broadcast and select (B&S) and route and select (R&S), and two possible implementations for the add/drop structures, the multicast switches (MCSs) and the wavelength selective switches (WSSs), were considered. The degradation of the optical communication network performance due to in-band crosstalk is assessed through the optical-signal-to-noise ratio (OSNR) calculation. In particular, an OSNR penalty of 1 dB due to in-band crosstalk is observed when the signal passes through a cascade of 19 CDC ROADMs with 16-degree, based on a R&S architecture and with add/drop structures implemented with WSSsOs nós das redes de comunicação ótica mais comuns são os multiplexadores óticos de inserção/extração reconfiguráveis (ROADMs – acrónimo anglo-saxónico de reconfigurable optical add/drop multiplexers). A arquitetura e componentes destes nós têm evoluído ao longo do tempo no sentido de se tornarem mais flexíveis e dinâmicos. Em particular, as estruturas de adição/extração destes nós, tornaram-se mais complexas e detêm novas características que oferecem as funcionalidades CDC (acrónimo anglo- -saxónico de colorless, directionless e contentionless). Uma das principais limitações do nível físico das redes óticas, o crosstalk homódino, deve-se principalmente ao isolamento imperfeito dos componentes presentes dentro destes nós. Este tipo de crosstalk tem um impacto ainda mais significativo quando o sinal ótico atravessa uma cadeia de nós baseados em ROADMs. Nesta dissertação, o impacto do crosstalk homódino, filtragem ótica e ruído ASE (acrónimo anglo-saxónico de amplified spontaneous emission) no desempenho de uma rede de comunicação ótica baseada numa cadeia de CDC ROADMs com deteção coerente e usando o formato de modulação PDM-QPSK (acrónimo anglo-saxónico de polarization-division multiplexing quadrature phase-shift keying) a um ritmo binário de 100-Gb/s é investigado através de simulação Monte-Carlo. Consideraram-se duas arquiteturas, B&S e R&S (acrónimos anglo-saxónicos para broadcast and select e route and select), e duas possíveis implementações para a estruturas de inserção/extração, os MCSs e os WSSs (acrónimos anglo-saxónicos de multicast switches e wavelengh selective switches). A degradação do desempenho da rede ótica devido ao crosstalk homódino foi obtida através do cálculo da relação sinal-ruído ótica. Em particular, obteve-se uma penalidade de 1 dB para esta relação devido ao crosstalk homódino quando o sinal percorre uma cadeia de 19 CDC ROADMs com grau 16, uma arquitetura R&S e estruturas de inserção/extração baseadas em WSSs