Mobility as a Service (MaaS) is a concept that aligns with both current and future mobility demands of users, namely intermodal, personalized, on-demand and seamless. Although the number of shared ...mobility, electric mobility and multimodal passenger transport users is rapidly growing, until now, the list of MaaS and electric Mobility as Service (eMaaS) providers is quite short. This could partly be explained by the lack of a common architecture that facilitates the complex integration of all actors involved in the (e)MaaS ecosystem. The goal of this publication is to give an overview of the state of the art regarding (e)MaaS’ ecosystems and architectures. Moreover, it aims to support the further development of eMaaS by proposing a definition and a novel system architecture for eMaaS. Firstly, the state of the art of the MaaS ecosystem is reviewed. Secondly, the eMaaS ecosystem that builds upon our definition of eMaaS is described and the MaaS system- and technical- architectures found in literature are reviewed. Finally, an eMaaS architecture that focuses on the integration of MaaS and electric mobility systems is presented. With the definition, ecosystem and system architecture presented in this work, the aim is to support the further development of the eMaaS concept.
A simple analytic expression for the far-field diffraction pattern of a general high-order Laguerre-Gaussian mode from a circular aperture is derived. Aperturing of the fundamental Gaussian beam is ...shown as a special case, where in the limit of waist size much larger than the aperture the Airy pattern is recovered and in the opposite limit we get a Gaussian intensity pattern. The diffraction pattern is shown to be an infinite series of Bessel functions and is strongly dependent on the ratio of the aperture area to the beam waist area (also known as the truncation parameter). This formulation leads to a more intuitive understanding of the far field of these modes, and the effect of the aperture as a spatial filter is discussed.
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1996.
Includes bibliographical references (leaves 115-123).
by Gadi Lenz.
Ph.D.
We propose a high-repetition-rate soliton-train source based on adiabatic compression of a dual-frequency optical signal in nonuniform fiber Bragg gratings. As the signal propagates through the ...grating, it is reshaped into a train of Bragg solitons whose repetition rate is predetermined by the frequency of initial sinusoidal modulation. We develop an approximate analytical model to predict the width of compressed soliton-like pulses and to provide conditions for adiabatic compression. We demonstrate numerically the formation of a 40-GHz train of 2.6-ps pulses and find that the numerical results are in good agreement with the predictions of our analytical model. The scheme relies on the dispersion provided by the grating, which can be up to six orders of magnitude larger than of fiber and makes it possible to reduce the fiber length significantly.
A design for a birefringent filter is described, which is suitable for tunable femtosecond lasers. Using a single plate, which has a steeply diving optic axis, two-octave tunability is attained with ...negligible deterioration of the stopband rejection. For a specific wavelength region, it means that the filter's bandwidth can be changed by a factor of four. Another characteristic of the design is that, for the same bandwidth, the proposed plate is five times thicker than a conventional plate in which the optic axis is parallel to the surface. Thus, etalon effects can be avoided. Tuning characteristics of color center lasers utilizing the new filter are also presented. (I.E.)
Time-domain measurements have been conducted in the 1.5-micron region of the spectrum to ascertain the group velocity dispersion in both a bulk and an MQW laser for TE and TM polarizations. The range ...of values obtained (-0.63 to -0.095/micron) is consistent with the results of other measurement techniques. Critical pulse-widths of less than 100 fsec have been computed and confirmed by cross-correlation measurements. The results obtained deepen insight into ultrashort propagation in diode lasers and amplifiers, and allow calculation of limitations on 100-fsec pulse generation and amplification in InGaAsP diode lasers. (O.C.)
Another model takes a IO Gb/s signal, demultiplexes it electrically to generate four 2.5 Gb/s signals which are then multiplexed optically using CWDM onto one fiber. After traveling 140 km and ...passing through an amplifier, it is optically de-multiplexed into four 2.5 Gb/s signals and electrically multiplexed into a IO Gb/s signal. Finally, it is demultiplexed electrically. The cost savings in this model is also in the 20% to 25% range.
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