# Manual Calculation Method

## Introduction

Scattering data generates an *.s file that you can export to OptiSystem. For more information on the *.s file and how to use it in OptiSystem, see the OptiBPM component NxM in the OptiSystem Component Library. OptiBPM uses scattering data when a small part of a larger photonic circuit is isolated for characterization using BPM…

## Innermost Loop

The first quantity needed is P , the Power in Output Waveguide. Calculate the electric field amplitude, a complex number b . The modulus of this complex number is just the square root of P , The real and imaginary parts of b are given by the optical phase θ as There are two terms contributing to…

## Central Wavelength Approximation

We can, however, employ an approximate solution which is much faster to compute. Concerning the wavelength interval, we are mostly dealing with a very small vicinity of a central wavelength. To save more simulation time, we can run the simulation just for this wavelength to obtain the one set of matrix elements. Let us call…

## BPM Calculations

Calculating θdelay If the BPM calculation contains regions, the reference index n0  might not have the same value throughout the calculation (see Figure 28). In this case, you must make a weighted sum of the regions. Figure 28: BPM layout with regions having different reference indices For the layout in Figure 28, the phase delay…

## Tilted Waveguides

Calculating θwg for tilted waveguides When the output waveguides are tilted, the phase becomes a sloped straight line. In You must be careful which point you use to calculate θwg . You must know exactly which point was used to make the information consistent with definitions used in the OptiSystem calculation. Figure 32 illustrates a…