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Basic Optical Waveguide Circuit
Published in Yasuo Kokubun, Lightwave Engineering, 2018
As can be seen in Equation (8.3), when E(1)(x) and E(2)(x) are equal, η is 1.0, but if they are not equal, it will always be smaller than 1. Normally, the coupling efficiency that is expressed in the form of −10 log10η in dB is called the coupling loss. Because this equation was derived by assuming the mode of a slab waveguide, the integral is expressed in the one-dimensional case, but in three-dimensional waveguides, such as optical fibers, the integral may be replaced with a double integral in the xy cross-section.
Modelling, simulation and evaluation of ground vibration caused by rail vehicles*
Published in Vehicle System Dynamics, 2019
David J. Thompson, Georges Kouroussis, Evangelos Ntotsios
When a new building is planned near an existing operational line, a similar technique can be used to estimate the levels of vibration and re-radiated noise in the proposed building. In this case, the characterisation of the vibration source can be performed more accurately, since vibration measurements can be made during the operation of trains on the existing line and used to estimate the vibration levels at the proposed location of the new building (Figure 6(b)). However, in this case, there is no available measured information about the vibration propagation from the soil into the building. Moreover, due to soil-structure interaction the actual response when the building is constructed could differ significantly from the measured ground response in the absence of the building. This difference is called the ‘coupling loss’ [14,24].
Recent progress and applications of optical microfiber and nanofiber devices
Published in Instrumentation Science & Technology, 2019
Qi Wang, Jian-Ying Jing, Bo-Tao Wang, Shuai Li
The coupling and propagation of the light in microfiber knot resonator are repeated so that the output spectrum is obtained.[42] The transmission matrix of the microfiber resonator is given by:[44] where and are the output light field, and are the input light field, is the coupling loss coefficient, and is the coupling coefficient. From (6),[43] where is the propagating constant. The insertion of (7) into (6) gives:[43]
An interval statistical energy method for high-frequency analysis of uncertain structural–acoustic coupling systems
Published in Engineering Optimization, 2020
J. H. Dong, F. W. Ma, Y. D. Hao, C. S. Gu
The power dissipated by the subsystem at a given circular frequency can be expressed as (Hynná, Klinge, and Vuoksinen 1995): where is a damping loss factor for the structural subsystem and is a damping loss factor for the acoustic cavity subsystem. The power transferred between subsystems can be expressed as where and denote energy coupling loss factors for the structural subsystem and acoustic cavity subsystem, respectively.