A Methodology to Assess the Impact of Optical and Electronic Crosstalk in a New Generation of Sensors Using Heritage Sensors

Electronic and optical crosstalk are radiometric challenges that often exist in the focal plane design in many sensors Such as MODIS. A methodology is described to assess the impact due to optical and electronic crosstalk on the measured radiance, and thereafter, the retrieval of geophysical products using MODIS Level I data sets. Based on a postulated set of electronic and optical crosstalk coefficients, and a set of MODIS scenes, we have simulated a system signal contamination on any detector on a focal plane when another detector on that focal plane is stimulated with a geophysical signal. The original MODIS scenes and the crosstalk impacted scenes can be used with validated geophysical algorithms to derive the final data products. Products contaminated with crosstalk are then compared to those without contamination to assess the impact magnitude and location, and will allow us to separate Out-Of-Band (OOB) leaks from hand-to-hand optical crosstalk, and identify potential failures to meet climate research requirements

MODIS and VIIRS Lunar Observations and Applications

Terra and Aqua MODIS have successfully operated for more than 13 and 11 years since their launch in 1999 and 2002, respectively. The VIIRS instrument on-board the S-NPP launched in 2011 has also operated for nearly 2 years. Both MODIS and VIIRS make observations in the reflective solar and thermal emissive regions and their on-orbit calibration and characterization are provided by a set of on-board calibrators (OBC). In addition, lunar observations have been made on a regular basis to support sensor on-orbit calibration. This paper provides a brief overview of MODIS and VIIRS instrument on-orbit calibration and characterization activities. It describes the approaches and strategies developed to schedule and perform on-orbit lunar observations. Specific applications of MODIS and VIIRS lunar observations discussed in this paper include radiometric calibration stability monitoring and performance assessment of sensor spatial characterization. Results derived from lunar observations, such as sensor response (or gain) trending and band-to-band registration, are compared with that derived from sensor OBC. The methodologies and applications presented in this paper can also be applied to other earth observing sensors

Post-Launch Calibration Support for VIIRS Onboard NASA NPP Spacecraft

The NPP Instrument Calibration Support Element (NICSE) is one of the elements within the NASA NPP Science Data Segment (SDS). The primary responsibility of NICSE is to independently monitor and evaluate on-orbit radiometric and geometric performance of the Visible Infrared Imaging Radiometer Suite (VIIRS) instrument and to validate its Sensor Data Record (SDR) [1]. The NICSE interacts and works closely with other SDS Product Evaluation and Analysis Tools Elements (PEATE) and the NPP Science Team (ST) and supports their on-orbit data product calibration and validation efforts. The NICSE also works closely with the NPP Instrument Calibration Support Team (NICST) during sensor pre-launch testing in ambient and thermal vacuum environment [2]. This paper provides an overview of NICSE VIIRS sensor post-launch calibration support with a focus on the use of sensor on-board calibrators (OBC) for the radiometric calibration and characterization. It presents the current status of NICSE post-launch radiometric calibration tool development effort based on its design requirement

Feasibility Study for an Aquatic Ecosystem Earth Observing System Version 1.2.

International audienceMany Earth observing sensors have been designed, built and launched with primary objectives of either terrestrial or ocean remote sensing applications. Often the data from these sensors are also used for freshwater, estuarine and coastal water quality observations, bathymetry and benthic mapping. However, such land and ocean specific sensors are not designed for these complex aquatic environments and consequently are not likely to perform as well as a dedicated sensor would. As a CEOS action, CSIRO and DLR have taken the lead on a feasibility assessment to determine the benefits and technological difficulties of designing an Earth observing satellite mission focused on the biogeochemistry of inland, estuarine, deltaic and near coastal waters as well as mapping macrophytes, macro-algae, sea grasses and coral reefs. These environments need higher spatial resolution than current and planned ocean colour sensors offer and need higher spectral resolution than current and planned land Earth observing sensors offer (with the exception of several R&D type imaging spectrometry satellite missions). The results indicate that a dedicated sensor of (non-oceanic) aquatic ecosystems could be a multispectral sensor with ~26 bands in the 380-780 nm wavelength range for retrieving the aquatic ecosystem variables as well as another 15 spectral bands between 360-380 nm and 780-1400 nm for removing atmospheric and air-water interface effects. These requirements are very close to defining an imaging spectrometer with spectral bands between 360 and 1000 nm (suitable for Si based detectors), possibly augmented by a SWIR imaging spectrometer. In that case the spectral bands would ideally have 5 nm spacing and Full Width Half Maximum (FWHM), although it may be necessary to go to 8 nm wide spectral bands (between 380 to 780nm where the fine spectral features occur -mainly due to photosynthetic or accessory pigments) to obtain enough signal to noise. The spatial resolution of such a global mapping mission would be between ~17 and ~33 m enabling imaging of the vast majority of water bodies (lakes, reservoirs, lagoons, estuaries etc.) larger than 0.2 ha and ~25% of river reaches globally (at ~17 m resolution) whilst maintaining sufficient radiometric resolution

Otimização de soluções de fotónica integrada para sistemas óticos de nova geração

Next generation optical systems can highly benefit from optimized photonic integrated solutions. Photonic integrated circuits (PIC) appear as a promising technology under the current demand for flexibility/reconfigurability in optical systems and telecommunications networks. PIC-based optical systems offer an efficient and cost-effective solution to data transmission increasing claims. In order to contribute to the development of integrated photonic technology, optimized PIC solutions addressing different steps of the PIC development chain, mainly design, testing, and packaging processes, are investigated. Optical signal data compression techniques are progressing to sustain the fast processing/storing of large amounts of bandwidth demanding data, with the advantage of resorting to photonic integrated solutions for the implementation of optical transforms, e.g., Haar transform (HT). This demand motivated the research of an optimized PIC design solution in silicon nitride (Si3N4) based platform comprising a two-level HT network for compression, and a switching network as a framework that supplies all logical inputs of the HT network for testing/characterization purposes. Optimized design models for the multimode interference key building block structure of the PIC design solution, are proposed. Additionally, a first test and characterization of PIC solutions implementing the HT for compression applications in indium phosphide (InP) based platform and in a new organic-inorganic hybrid material were realized. Taking advantage of a tunable lattice filter dispersion compensator in Si3N4-based integrated platform, it was demonstrated a real-time extended reach PAM-4 transmission over 40 km enabled by the photonic integrated dispersion compensator, with application in data center interconnects. Under photonic integrated high-Q resonators need for accurate performance measurement, a technique based on RF calibrated Mach-Zehnder interferometer, and Brillouin gain measurements through Lorentzian fitting analysis were successfully attained. Finally, as technical and functional requirements of PIC demand a thorough characterization/testing to provide an accurate prediction of its performance, and current testing platforms can be expensive and have low flexibility, a proof of concept of a new soft-packaging flexible platform for photonic integrated processors and spatial division multiplexing systems, based in spatial light modulation operation principle is proposed.Os sistemas óticos de nova geração beneficiam com a otimização de fotónica integrada. Com os circuitos de fotónica integrada (PIC) avançados a surgir como uma tecnologia promissora, dentro da crescente procura por flexibilidade/ reconfigurabilidade dos sistemas óticos e redes de telecomunicações. Os sistemas óticos baseados em PIC oferecem soluções eficientes e rentáveis em resposta às necessidades crescentes de transmissão de dados. De modo a contribuir para o desenvolvimento tecnológico associado à fotónica integrada, são investigados no âmbito desta dissertação diferentes soluções otimizadas de PIC, abordando diferentes estágios do seu desenvolvimento, nomeadamente projeto/design, teste e encapsulamento. Técnicas de compressão de sinais óticos estão a progredir no sentido de apoiar a expansão de velocidade de processamento e quantidade de armazenamento com elevada largura de banda associada. São esperadas vantagens recorrendo a PIC para a implementação de transformadas óticas, e.g., transformada de Haar (HT). Esta necessidade motivou a investigação de soluções de PIC com design otimizado, desenvolvidas em plataforma integrada de nitreto de silício (Si3N4). O PIC desenhado é constituído por uma rede 2D a executar a HT para fins de compressão e uma rede de comutação para produzir todas as entradas lógicas esperadas para teste e caracterização. São propostos modelos de design otimizados para a estrutura elementar que compõe o PIC, i.e., componente de interferência multimodal. Adicionalmente, foi realizado o primeiro teste e caracterização experimental de um PIC implementando a HT para fins de compressão, numa plataforma integrada de fosfato de índio (InP) e num material orgânico-inorgânico híbrido. Tirando partido de um filtro sintonizável para compensação de dispersão, desenvolvido em plataforma integrada de Si3N4, foi demostrado um link de transmissão alargada (40 km) em modulação PAM-4, com possível aplicação em centros de processamento de dados de interconexão. A necessidade de medições precisas de desempenho para a caracterização efetiva de soluções integradas de ressoadores de elevado fator de qualidade, motivou a implementação de uma técnica de medição eficaz. Esta é baseada num interferómetro de Mach-Zehnder calibrado em rádio frequência e na realização de mediações de ganho de Brillouin por análise Lorentziana de ajuste de curva. Por fim, tendo em conta os rigorosos requisitos técnicos e funcionais associados ao teste/caracterização precisa de PIC e o facto de as atuais soluções serem dispendiosas e pouco flexíveis. Uma prova de conceito de uma nova plataforma flexível de encapsulamento por software é proposta com aplicação em processadores PIC e sistemas com multiplexagem por divisão espacial.Programa Doutoral em Telecomunicaçõe

Enabling Technology in Optical Fiber Communications: From Device, System to Networking

This book explores the enabling technology in optical fiber communications. It focuses on the state-of-the-art advances from fundamental theories, devices, and subsystems to networking applications as well as future perspectives of optical fiber communications. The topics cover include integrated photonics, fiber optics, fiber and free-space optical communications, and optical networking

Telecommunication Systems

This book is based on both industrial and academic research efforts in which a number of recent advancements and rare insights into telecommunication systems are well presented. The volume is organized into four parts: "Telecommunication Protocol, Optimization, and Security Frameworks", "Next-Generation Optical Access Technologies", "Convergence of Wireless-Optical Networks" and "Advanced Relay and Antenna Systems for Smart Networks." Chapters within these parts are self-contained and cross-referenced to facilitate further study