We developed model and unveiled the mechanism of the large wavelength-dependent attenuation (WDA) that has been hindering the development of tilting-mirror MEMS VOA. We developed a new tilting-mirror VOA with low WDA of <0.1dB at 20dB attenuation.
We have designed and fabricated PIN photodiode based ROSA used for FTTX applications. The critical nonlinearity parameters of Inter-modulation Distortion (IMD) were measured by two RF modulated light sources near 1550nm wavelength channels. A cost effective measuring system with narrow pass band filter was set up and some procedures were utilized for determining the low level signals of IMD. Obtained test results were used in real time to guide packaging process to achieve best receiver performance.
Reconfigurable optical add/drop multiplexer (ROADM) is a next generation critical component that facilitates the
network system evolution from a point-to-point transmission-oriented structure to an all-optical, wavelength-flexible,
dynamic network. ROADM enables flexible removal and insertion of WDM channels at either a head-end or
intermediate nodes-making it possible for true network provisioning and reconfiguration.
We will review the pros and cons of each of the techniques for tunable OADM, from their operating principles to their
practical implementations with special emphasis on two approaches: a TTF based three-port tunable filter as a basic
one-channel tunable add/drop multipexer and a full-scale, MEMS mirror array based 80-channel reconfigurable OADM
subsystem. Comparative laboratory experimental results with theoretical calculations are presented.
Reconfigurable Add/drop Multiplexer (ROADM) is a broad definition of a functionally reconfigurable filtering device for dynamic networking. We focus on a class of ROADM architecture that allows scalability of wavelength channels, add/drop port counts as well as functional capability of integrating variable attenuation and monitoring elements. We demonstrate the proposed concepts of integrating a ROADM with a variable optical attenuator and a performance monitor array.
High intensity nonresonant multiphoton ionization has been used in conjunction with time-of-flight mass spectrometry to perform highly sensitive, quantitative, chemical analysis. To achieve quantification of all elements simultaneously and obtain uniform detection efficiencies, all species, regardless of ionization potentials, should be saturated in a single, well-defined volume. To aid in this analysis, 3D potentials intensity distributions of high power laser beams were imaged at a nd near their focus. The cross-sectional intensity distributions of the fundamental and higher order harmonics of a 35-ps Nd:YAG laser beam showed near Gaussian profiles. For nonresonant multiphoton ionization of sputtered or gaseous atoms and molecules, high laser beam quality combined with high power density led not only to photo-ionization saturation of species with quite different ionization potentials, but also to sharply defined ionization volumes. Experiments were performed on the nonresonant multiphoton ionization of species from solid samples and from gaseous samples using well-characterized, high intensity laser beams. The result, driving relative sensitivity factors almost to unity, demonstrate quantitative compositional analysis.