Contents
How does the mode-finite difference eigenmode solver work?
The solver calculates the mode field profiles, effective index, and loss. Integrated frequency sweep makes it easy to calculate group delay, dispersion, etc. The solver can also treat bent waveguides. In the z-normal eigenmode solver simulation example shown in the figure below, we have the vector fields:
How is the eigenfrequency of a structure determined?
An eigenfrequency analysis can only provide the shape of the mode, not the amplitude of any physical vibration. The true size of the deformation can only be determined if an actual excitation is known together with damping properties. Determining the eigenfrequencies of a structure is an important part of structural engineering.
When does the FDE solve an eigenvalue problem?
Note: The FDE solves an eigenvalue problem where beta2 (beta square) is the eigenvalue (see the reference below) and in some cases, such as evanescent modes or waveguides made from lossy material, beta2 is a negative or complex number. The choice of root for beta2 determines if we are returning the forward or backward propagating modes.
Which is the lowest eigenfrequency in two DOF system?
For the two-DOF system above, the first eigenmode (corresponding to the lowest eigenfrequency) consists of both masses moving in the same direction; whereas in the second eigenmode, the masses move in opposite directions. This is illustrated below for an undamped two-DOF system with, where the natural frequencies are
How many circumferential waves are in the eigenmode?
As mentioned earlier the eigenmode has n = 10 circumferential waves equally spaced in the hoop direction and positioned at the junction between the knuckle and spherical portion of the dome. Fig. 7.4.16 shows the sensitivity of buckling pressure to eigenmode affine shape perturbation within the scaling factor, 0.0 < δ 0 /t ≤ 2.0.
What is the eigenmode of a top surface field?
Top-surface fields , 4-nm L/S Absorber thickness = 103.4 nm •At X = 24 nm, the n = 2 eigenmode field is again approximately equal to but 180oout of phase with the top-surface reflected field, leading to almost zero at the position of aerial-image minimum.
How big is the eigenmode field at x = 24 nm?
•At X = 24 nm, the n = 2 eigenmode field is approximately equal to and in phase with the top-surface reflected field, leading to a large value at the position of aerial-image minimum. Top-surface fields , 4-nm L/S Absorber thickness = 103.4 nm