Sweep Taper Length

Find the S-matrix of a taper for different taper lengths

from typing import List

import matplotlib.pyplot as plt
import meow as mw
import numpy as np
from tqdm.notebook import tqdm

Installation

pip install meow-sim

Quick Start

1. Structure

def create_structures(length=10.0):
    oxide = mw.Structure(
        material=mw.silicon_oxide,
        geometry=mw.Prism(
            poly=np.array([(0, -2.1), (10, -2.1), (10, 2.1), (0, 2.1)]),
            h_min=-3,
            h_max=0,
            axis="y",
        ),
    )

    poly = np.array([(0, -0.45 / 2), (10, -1), (10, 1), (0, 0.45 / 2)])

    core = mw.Structure(
        material=mw.silicon,
        geometry=mw.Prism(
            poly=poly,
            h_min=0,
            h_max=0.22,
            axis="y",
        ),
    )

    structures = [oxide, core]
    return structures

mw.visualize(create_structures())

2. Cells

def create_cells(length=10.0, cell_length=1.0):
    num_cells = round(length / cell_length)
    structures = create_structures(length=length)
    cells = mw.create_cells(
        structures=structures,
        mesh=mw.Mesh2D(
            x=np.linspace(-2, 2, 101),
            y=np.linspace(-2, 2, 101),
            # specify possible conformal mesh specifications here:
            # bend_radius=2.0,
            # bend_axis=1,
        ),
        Ls=np.array([length / num_cells for _ in range(num_cells)]),
    )
    return cells

cells = create_cells()
mw.visualize(cells[-1])

3. Cross Sections

def create_cross_sections(length=10.0, cell_length=1.0, wl=1.55, T=25.0):
    cells = create_cells(length=length, cell_length=cell_length)
    env = mw.Environment(wl=1.55, T=25.0)
    css = [mw.CrossSection.from_cell(cell=cell, env=env) for cell in cells]
    return css

css = create_cross_sections()
mw.visualize(css[0])

4. Find Modes (FDE)

def find_modes(length=10.0, cell_length=1.0, wl=1.55, T=25.0, num_modes=10):
    css = create_cross_sections(length=length, cell_length=cell_length, wl=wl, T=T)
    modes: List[List[mw.Mode]] = []
    for cs in tqdm(css):
        modes_in_cs = mw.compute_modes(cs, num_modes=num_modes)
        modes.append(modes_in_cs)
    return modes

5. Calculate S-matrix (EME)

def find_s_matrix(length=10.0, cell_length=1.0, wl=1.55, T=25.0, num_modes=10):
    modes = find_modes(
        length=length, cell_length=cell_length, wl=wl, T=T, num_modes=num_modes
    )
    S, port_map = mw.compute_s_matrix(modes, cell_lengths=[cell_length for _ in modes])
    return S, port_map

S1, pm1 = find_s_matrix(length=10.0)
S2, pm2 = find_s_matrix(length=5.0)

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mw.visualize((abs(S1), pm1))

mw.visualize((abs(S2), pm2))