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add more models
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‎src/sax/models/__init__.py‎

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passthru,
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unitary,
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)
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from .isolators import (
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circulator,
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isolator,
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)
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from .mmis import (
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mmi1x2,
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mmi1x2_ideal,
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from .probes import (
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ideal_probe,
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)
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from .reflectors import (
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mirror,
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reflector,
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)
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from .splitters import (
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splitter_ideal,
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)
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phase_shifter,
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straight,
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)
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from .terminators import (
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terminator,
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)
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__all__ = [
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"attenuator",
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"bend",
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"circulator",
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"copier",
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"coupler",
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"coupler_ideal",
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"crossing_ideal",
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"grating_coupler",
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"ideal_probe",
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"isolator",
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"mirror",
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"mmi1x2",
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"mmi1x2_ideal",
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"mmi2x2",
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"model_4port",
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"passthru",
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"phase_shifter",
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"reflector",
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"rf",
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"splitter_ideal",
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"straight",
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"terminator",
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"unitary",
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]

‎src/sax/models/isolators.py‎

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"""SAX Isolator and Circulator Models."""
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from __future__ import annotations
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import jax
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import jax.numpy as jnp
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from pydantic import validate_call
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import sax
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@jax.jit
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@validate_call
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def isolator(
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*,
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wl: sax.FloatArrayLike = sax.WL_C,
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insertion_loss_dB: sax.FloatArrayLike = 0.0,
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isolation_dB: sax.FloatArrayLike = 40.0,
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) -> sax.SDict:
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"""Optical isolator model (non-reciprocal).
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Transmits light in the forward direction (in0 -> out0) with low loss
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while blocking the reverse direction (out0 -> in0).
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```{svgbob}
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in0 out0
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o1 ====>====== o2
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```
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Args:
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wl: Wavelength in micrometers.
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insertion_loss_dB: Forward insertion loss in dB. Defaults to 0.0 dB.
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isolation_dB: Reverse isolation in dB. Higher values mean better
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blocking of backward-propagating light. Defaults to 40.0 dB.
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Returns:
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S-matrix dictionary for the isolator.
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Examples:
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Isolator with 1 dB insertion loss and 30 dB isolation:
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```python
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# mkdocs: render
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import matplotlib.pyplot as plt
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import numpy as np
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import sax
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sax.set_port_naming_strategy("optical")
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wl = sax.wl_c()
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s = sax.models.isolator(
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wl=wl,
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insertion_loss_dB=1.0,
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isolation_dB=30.0,
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)
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fwd = np.abs(s[("o1", "o2")]) ** 2
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bwd = np.abs(s[("o2", "o1")]) ** 2
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plt.figure()
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plt.plot(wl, 10 * np.log10(fwd), label="forward")
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plt.plot(wl, 10 * np.log10(bwd + 1e-10), label="backward")
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plt.xlabel("Wavelength [μm]")
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plt.ylabel("Transmission [dB]")
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plt.legend()
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```
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"""
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one = jnp.ones_like(jnp.asarray(wl))
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forward = jnp.asarray(10 ** (-insertion_loss_dB / 20), dtype=complex) * one
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backward = jnp.asarray(10 ** (-isolation_dB / 20), dtype=complex) * one
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return {
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("o1", "o2"): forward,
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("o2", "o1"): backward,
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}
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@jax.jit
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@validate_call
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def circulator(
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*,
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wl: sax.FloatArrayLike = sax.WL_C,
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insertion_loss_dB: sax.FloatArrayLike = 0.0,
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isolation_dB: sax.FloatArrayLike = 40.0,
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) -> sax.SDict:
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"""Optical circulator model (non-reciprocal 3-port device).
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Routes light in a circular fashion: port 1 -> port 2 -> port 3 -> port 1.
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Light traveling in the reverse direction is strongly attenuated.
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```{svgbob}
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o2
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*
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/ \\
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/ \\
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/ --> \\
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*-------*
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o1 o3
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```
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Args:
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wl: Wavelength in micrometers.
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insertion_loss_dB: Insertion loss in dB for the forward circulation
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path. Defaults to 0.0 dB.
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isolation_dB: Isolation in dB between non-adjacent ports (reverse
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direction). Defaults to 40.0 dB.
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Returns:
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S-matrix dictionary for the circulator.
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Examples:
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3-port circulator:
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```python
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# mkdocs: render
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import matplotlib.pyplot as plt
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import numpy as np
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import sax
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sax.set_port_naming_strategy("optical")
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wl = sax.wl_c()
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s = sax.models.circulator(
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wl=wl,
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insertion_loss_dB=0.5,
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isolation_dB=30.0,
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)
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fwd_12 = np.abs(s[("o1", "o2")]) ** 2
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fwd_23 = np.abs(s[("o2", "o3")]) ** 2
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iso_21 = np.abs(s[("o2", "o1")]) ** 2
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plt.figure()
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plt.plot(wl, 10 * np.log10(fwd_12), label="o1→o2")
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plt.plot(wl, 10 * np.log10(fwd_23), label="o2→o3")
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plt.plot(wl, 10 * np.log10(iso_21 + 1e-10), label="o2→o1 (isolated)")
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plt.xlabel("Wavelength [μm]")
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plt.ylabel("Transmission [dB]")
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plt.legend()
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```
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"""
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one = jnp.ones_like(jnp.asarray(wl))
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forward = jnp.asarray(10 ** (-insertion_loss_dB / 20), dtype=complex) * one
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isolated = jnp.asarray(10 ** (-isolation_dB / 20), dtype=complex) * one
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return {
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# Forward circulation: o1 -> o2 -> o3 -> o1
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("o1", "o2"): forward,
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("o2", "o3"): forward,
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("o3", "o1"): forward,
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# Reverse (isolated): o2 -> o1, o3 -> o2, o1 -> o3
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("o2", "o1"): isolated,
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("o3", "o2"): isolated,
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("o1", "o3"): isolated,
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}

‎src/sax/models/reflectors.py‎

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"""SAX Reflector Models."""
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from __future__ import annotations
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import jax
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import jax.numpy as jnp
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from pydantic import validate_call
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import sax
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@jax.jit
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@validate_call
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def reflector(
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*,
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wl: sax.FloatArrayLike = sax.WL_C,
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reflection: sax.FloatArrayLike = 0.5,
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loss_dB: sax.FloatArrayLike = 0.0,
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) -> sax.SDict:
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r"""Partial reflector / mirror model.
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A 2-port component that reflects a fraction of the input power and
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transmits the rest (minus any loss).
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```{svgbob}
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in0 | out0
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o1 ========= | ========= o2
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|
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mirror
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```
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Args:
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wl: Wavelength in micrometers.
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reflection: Power reflection coefficient between 0 and 1.
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0 means full transmission, 1 means full reflection. Defaults to 0.5.
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loss_dB: Insertion loss in dB applied to both reflected and
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transmitted amplitudes. Defaults to 0.0 dB.
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Returns:
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S-matrix dictionary for the reflector.
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Examples:
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50% reflector:
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```python
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# mkdocs: render
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import matplotlib.pyplot as plt
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import numpy as np
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import sax
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sax.set_port_naming_strategy("optical")
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wl = sax.wl_c()
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s = sax.models.reflector(wl=wl, reflection=0.5)
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thru = np.abs(s[("o1", "o2")]) ** 2
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refl = np.abs(s[("o1", "o1")]) ** 2
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plt.figure()
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plt.plot(wl, thru, label="transmission")
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plt.plot(wl, refl, label="reflection")
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plt.xlabel("Wavelength [μm]")
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plt.ylabel("Power")
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plt.legend()
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```
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"""
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one = jnp.ones_like(jnp.asarray(wl))
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loss_amp = jnp.asarray(10 ** (-loss_dB / 20), dtype=complex) * one
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r = jnp.asarray(reflection**0.5, dtype=complex) * loss_amp
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t = jnp.asarray((1 - reflection) ** 0.5, dtype=complex) * loss_amp
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p = sax.PortNamer(1, 1)
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return sax.reciprocal(
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{
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(p.in0, p.in0): r,
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(p.in0, p.out0): t,
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(p.out0, p.out0): r,
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}
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)
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@jax.jit
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@validate_call
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def mirror(
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*,
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wl: sax.FloatArrayLike = sax.WL_C,
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reflection: sax.FloatArrayLike = 1.0,
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loss_dB: sax.FloatArrayLike = 0.0,
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) -> sax.SDict:
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r"""Ideal mirror model (reflector with default 100% reflection).
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```{svgbob}
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in0 ||
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o1 ========= ||
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||
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mirror
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```
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Args:
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wl: Wavelength in micrometers.
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reflection: Power reflection coefficient between 0 and 1.
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Defaults to 1.0 (perfect mirror).
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loss_dB: Insertion loss in dB. Defaults to 0.0 dB.
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Returns:
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S-matrix dictionary for the mirror.
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Examples:
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Perfect mirror:
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```python
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# mkdocs: render
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import matplotlib.pyplot as plt
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import numpy as np
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import sax
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sax.set_port_naming_strategy("optical")
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wl = sax.wl_c()
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s = sax.models.mirror(wl=wl)
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refl = np.abs(s[("o1", "o1")]) ** 2
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plt.figure()
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plt.plot(wl, refl, label="reflection")
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plt.xlabel("Wavelength [μm]")
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plt.ylabel("Power")
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plt.legend()
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```
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"""
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return reflector(wl=wl, reflection=reflection, loss_dB=loss_dB)

‎src/sax/models/rf.py‎

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@@ -207,6 +207,49 @@ def admittance(
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return sax.reciprocal(sdict)
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@partial(jax.jit, inline=True)
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def resistor(
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*,
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f: sax.FloatArrayLike = DEFAULT_FREQUENCY,
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resistance: sax.FloatLike = 50,
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z0: sax.ComplexLike = 50,
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) -> sax.SDict:
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r"""Ideal two-port resistor model.
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Args:
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f: Frequency in Hz
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resistance: Resistance in Ohms
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z0: Reference impedance in Ω.
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Returns:
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S-dictionary representing the resistor element
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References:
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[@pozar2012]
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Examples:
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```python
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# mkdocs: render
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import matplotlib.pyplot as plt
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import numpy as np
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import sax
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sax.set_port_naming_strategy("optical")
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f = np.linspace(1e9, 10e9, 500)
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s = sax.models.rf.resistor(f=f, resistance=100, z0=50)
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plt.figure()
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plt.plot(f / 1e9, np.abs(s[("o1", "o1")]), label="|S11|")
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plt.plot(f / 1e9, np.abs(s[("o1", "o2")]), label="|S12|")
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plt.plot(f / 1e9, np.abs(s[("o2", "o2")]), label="|S22|")
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plt.xlabel("Frequency [GHz]")
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plt.ylabel("Magnitude")
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plt.legend()
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```
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"""
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return impedance(f=f, z=resistance, z0=z0)
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@partial(jax.jit, inline=True)
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def capacitor(
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*,

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