Analysis device and analysis method

1. An analysis apparatus for analyzing optical characteristics of a physical optical connection structure which has a distribution of an electromagnetic field in which many modes are combined, the analysis apparatus comprising:

a setting device configured to set information on a structure of an optical connection structure based on a physical property value of the optical connection structure, wherein the optical connection structure includes a first waveguide, a second waveguide, and an optical element optically connecting the first waveguide and the second waveguide to each other;

a solution device configured to solve a partial differential equation having, as an unknown, an electromagnetic field distributed in the optical connection structure based on the information on the structure of the optical connection structure to determine a distribution of the electromagnetic field, wherein the solution device comprises:

a first distribution calculation device configured to calculate the distribution of the electromagnetic field in the optical connection structure; and

a second distribution calculation device configured to calculate a distribution of a reference electric field indicating a distribution of an electromagnetic field of a region included in the first waveguide and the optical element when electromagnetic waves propagate from the first waveguide towards the second waveguide;

a data extraction device configured to extract, from the distribution of the electromagnetic field determined by the solution device, a mode distribution in a plane at a predetermined position of the optical connection structure and a time response of an electromagnetic field at a predetermined position of the optical connection structure, wherein the data extraction device comprises:

a first response calculation device configured to obtain a temporal change of an electric field at first reference coordinate set at a position intersecting an optical axis of the optical element by the distribution of the electromagnetic field calculated by the first distribution calculation device;

a second response calculation device configured to obtain a temporal change of an electric field at second reference coordinate set at a position intersecting the optical axis of the second waveguide by the distribution of the electromagnetic field calculated by the first distribution calculation device; and

a third response calculation device configured to obtain a temporal change of the reference electric field at the first reference coordinate set from the distribution of the reference electric field calculated by the second distribution calculation device;

a characteristics analysis device configured to analyze optical characteristics of the optical connection structure based on the mode distribution and the time response of the electromagnetic field extracted by the data extraction device; and

an evaluation device configured to determine whether to modify the physical property value of the optical connection structure based on the optical characteristics output by the characteristic analysis device.

2. The analysis apparatus according to claim 1 , wherein:

the solution device includes:

a waveguide mode calculation device configured to calculate a waveguide mode indicating an electromagnetic field in which zeroth or higher order eigenmodes are combined when reflection does not occur on an end surface of the first waveguide facing the optical element, wherein the first distribution calculation device is configured to calculate the distribution of the electromagnetic field based on the waveguide mode.

3. The analysis apparatus according to claim 2 , wherein:

the solution device includes an eigenmode calculation device configured to calculate an eigenmode of the second waveguide;

the data extraction device includes a mode distribution extraction device configured to extract a mode distribution within a cross section intersecting an optical axis of the second waveguide; and

the characteristics analysis device includes a coupling efficiency calculation device configured to calculate a coupling efficiency of the eigenmode and the mode distribution based on the eigenmode calculated by the eigenmode calculation device and the mode distribution extracted by the mode distribution extraction device.

4. The analysis apparatus according to claim 1 , wherein the characteristics analysis device includes a reflectance calculation device configured to calculate a reflectance at the first reference coordinate set based on the temporal change of the electric field at the first reference coordinate set obtained by the first response calculation device and the temporal change of the reference electric field obtained by the third response calculation device.

5. The analysis apparatus according to claim 1 , wherein the characteristics analysis device includes a transmittance calculation device configured to calculate a transmittance at the second reference coordinate set based on the temporal change of the electric field at the second reference coordinate set obtained by the second response calculation device and the temporal change of the reference electric field obtained by the third response calculation device.

6. The analysis apparatus according to claim 1 , further comprising:

an evaluation device configured to evaluate the structure of the optical connection structure set by the setting device based on preset optical characteristics from optical characteristics of the optical connection structure analyzed by the characteristics analysis device.

7. An analysis method for analyzing optical characteristics of a physical optical connection structure which has a distribution of an electromagnetic field in which many modes are combined, the method comprising:

setting information on a structure of an optical connection structure based on a physical property value of the optical connection structure, wherein the optical connection structure comprises includes a first waveguide, a second waveguide, and an optical element optically connecting the first waveguide and the second waveguide to each other;

solving a partial differential equation having, as an unknown, an electromagnetic field distributed in the optical connection structure based on the information on the structure of the optical connection structure to determine a distribution of the electromagnetic field;

calculating a distribution of a reference electric field indicating a distribution of an electromagnetic field of a region included in the first waveguide and the optical element when electromagnetic waves propagate from the first waveguide toward the second waveguide;

obtaining, from the distribution of the electromagnetic field, a mode distribution in a plane at a predetermined position of the optical connection structure and a time response of an electromagnetic field at a predetermined position of the optical connection structure, wherein obtaining the mode distribution and the time response of the electromagnetic field comprises:

obtaining a temporal change of an electric field at first reference coordinate set at a position intersecting an optical axis of the optical element by the distribution of the electromagnetic field of the region included in the optical connection structure;

obtaining a temporal change of an electric field at second reference coordinate set at a position intersecting the optical axis of the second waveguide by the distribution of the electromagnetic field of the region included in the optical connection structure, and

obtaining a temporal change of the reference electric field at the first reference coordinate set from the distribution of the reference electric field;

analyzing optical characteristics of the optical connection structure based on the mode distribution and the time response of the electromagnetic field; and

determining whether to modify the physical property value of the optical connection structure based on the optical characteristics.

8. The method according to claim 7 , wherein solving the partial differential equation to determine the distribution of the electromagnetic field further comprises:

calculating a waveguide mode indicating an electromagnetic field in which zeroth or higher order eigenmodes are combined when reflection does not occur on an end surface of the first waveguide facing the optical element, wherein calculating the distribution of the electromagnetic field comprises calculating the distribution of the electromagnetic field based on the waveguide mode.