straight

直波导是光子集成链路不可或缺的组件。

创建步骤如下:

导入库:

from dataclasses import dataclass
from functools import cached_property
from typing import Tuple

from fnpcell import all as fp
from fnpcell.interfaces import angle_between, distance_between
from gpdk.technology import get_technology, PCell

定义直波导类:

@dataclass(eq=False)
class Straight(fp.IWaveguideLike, PCell):

    length: float = fp.FloatParam(default=10, min=0)
    waveguide_type: fp.IWaveguideType = fp.WaveguideTypeParam()
    anchor: fp.Anchor = fp.AnchorParam(default=fp.Anchor.START)
    port_names: fp.IPortOptions = fp.PortOptionsParam(count=2, default=("op_0", "op_1"))

    def _default_waveguide_type(self):
        return get_technology().WG.FWG.C.WIRE

    @cached_property
    def raw_curve(self):
        return fp.g.Line(
            length=self.length,
            anchor=self.anchor,
        )

    def build(self) -> Tuple[fp.InstanceSet, fp.ElementSet, fp.PortSet]:
        insts, elems, ports = super().build()
        wg = self.waveguide_type(curve=self.raw_curve).with_ports(self.port_names)
        insts += wg
        ports += wg.ports
        return insts, elems, ports

    @fp.cache()
    def sim_model(self, env: fp.ISimEnv):
        # We can use simple straight waveguide model or calculate s-matrix ourselves
        # return fp.sim.StraightWaveguideModel(self.waveguide_type.theoretical_parameters, length=self.length)
        import numpy as np

        TECH = get_technology()
        op_0, op_1 = self["op_0"], self["op_1"]  # TODO should use [self[name] for name in self.port_names], consider Hidden / None
        params = fp.sim.TheoreticalParameters(self.waveguide_type.theoretical_parameters)

        # we can get wavelength from env
        # wavelength = env.wavelength * TECH.METRICS.UNIT  # wavelength in um => m
        wl = np.asanyarray(params.wl) * TECH.METRICS.UNIT  # wavelength in um => m
        n_eff = np.asanyarray(params.n_eff)
        loss = np.asanyarray(params.loss) * 1e2  # loss in dB/cm => dB/m
        length = self.length * TECH.METRICS.UNIT  # length in um => m

        mag = 10 ** (-loss * length / 20)
        ang = 2 * np.pi * n_eff * length / wl

        S = fp.sim.SMatrix()
        # These two lines below are equal
        # S[op_1 <= op_0] = S[op_0["TE"] <= op_1["TE"]] = mag, ang
        S[op_1, op_0] = S[op_0["TE"], op_1["TE"]] = mag, ang

        # metadata is optional
        metadata = {
            "ports": {
                op_0.name: "LEFT",
                op_1.name: "RIGHT",
            }
        }
        return fp.sim.SMatrixWavelengthModel(wl, S, metadata=metadata)

这个类定义通过以下方法调用实现版图设计:

TECH = get_technology()
    straight = Straight(name="s", length=10, waveguide_type=TECH.WG.FWG.C.WIRE)
fp.plot(straight)

这个类里面定义的仿真可以用于整体链路的仿真。

此外，还需要定义端口之间直波导链接的函数:

def StraightBetween(
    *,
    start: fp.Point2D = (0, 0),
    end: fp.Point2D,
    waveguide_type: fp.IWaveguideType,
    port_names: fp.IPortOptions = ("op_0", "op_1"),
):
    length = distance_between(end, start)
    orientation = angle_between(end, start)
    straight = Straight(length=length, waveguide_type=waveguide_type, port_names=port_names).rotated(radians=orientation).translated(*start)
    return straight

运行案例，得到的版图文件为: