bend_euler
实践证明，作为非线性曲率的欧拉弯曲拥有更好的传输性能。本小节将创建欧拉弯曲组件。
创建步骤如下:
导入库:
from dataclasses import dataclass
from functools import cached_property
from typing import Optional, Tuple
from fnpcell import all as fp
from gpdk.technology import get_technology, PCell
from gpdk.technology.interfaces import CoreCladdingWaveguideType
定义欧拉弯曲类:
@dataclass(eq=False)
class BendEuler(fp.IWaveguideLike, PCell):
"""
Attributes:
degrees: central angle in degrees
radius_min: radius minimum
p: radio of euler spiral in whole bend, 0 < p <= 1, when p = 1, there's no cirular part in the bend
l_max: max length of euler spiral in half bend
choose either p or l_max
waveguide_type: type of waveguide of the bend
port_names: defaults to ["op_0", "op_1"]
Examples:
```python
TECH = get_technology()
bend = BendEuler(name="e90", radius_min=10, degrees=90, waveguide_type=TECH.WG.FWG.C.WIRE)
fp.plot(bend)
```
"""
degrees: float = fp.DegreeParam(default=90, min=-180, max=180, doc="Bend angle in degrees")
radius_eff: float = fp.PositiveFloatParam(required=False, doc="Bend radius_eff")
radius_min: float = fp.PositiveFloatParam(required=False, doc="Bend radius_min")
p: Optional[float] = fp.PositiveFloatParam(required=False, max=1, doc="Bend parameter")
l_max: Optional[float] = fp.PositiveFloatParam(required=False, doc="Bend Lmax")
waveguide_type: fp.IWaveguideType = fp.WaveguideTypeParam(doc="Waveguide parameters")
port_names: fp.IPortOptions = fp.PortOptionsParam(count=2, default=["op_0", "op_1"])
def _default_radius_eff(self):
if self.radius_min is None:
return 10
def _default_waveguide_type(self):
return get_technology().WG.FWG.C.WIRE
def __post_pcell_init__(self):
assert self.radius_eff is not None or self.radius_min is not None, "either radius_eff or radius_min must be provided"
@cached_property
def raw_curve(self):
radius_min = self.radius_min
if radius_min is None:
radius_min = self.radius_eff
curve = fp.g.EulerBend(radius_min=radius_min, degrees=self.degrees, p=self.p, l_max=self.l_max)
if self.radius_min is None and not fp.is_close(curve.radius_eff, self.radius_eff):
curve = curve.scaled(self.radius_eff / curve.radius_eff)
return curve
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
定义90度欧拉弯曲类:
@dataclass(eq=False)
class BendEuler90(BendEuler):
"""
Attributes:
slab_square: bool, whether draw a square clad
radius_min: radius minimum
radius_eff: radius effective
choose either radius_min(imum) or radius_eff(ective)
p: radio of euler spiral in whole bend, 0 < p <= 1, when p = 1, there's no cirular part in the bend
l_max: max length of euler spiral in half bend
choose either p or l_max
waveguide_type: type of waveguide of the bend
port_names: defaults to ["op_0", "op_1"]
Examples:
```python
TECH = get_technology()
bend = BendEuler90(name="e90c", radius_min=10, slab_square=True, waveguide_type=TECH.WG.FWG.C.WIRE)
fp.plot(bend)
```
"""
degrees: float = fp.DegreeParam(default=90, min=90, max=90, locked=True, doc="Bend angle in degrees")
waveguide_type: CoreCladdingWaveguideType = fp.WaveguideTypeParam(type=CoreCladdingWaveguideType, doc="Waveguide parameters")
slab_square: bool = fp.BooleanParam(required=False, default=False, doc="whether draw a square clad")
def build(self) -> Tuple[fp.InstanceSet, fp.ElementSet, fp.PortSet]:
insts, elems, ports = super().build()
waveguide_type = self.waveguide_type
if self.slab_square:
r = self.raw_curve.radius_eff
w = r + waveguide_type.cladding_width / 2
x = w / 2
y = (r - waveguide_type.cladding_width / 2) / 2
elems += fp.el.Rect(width=w, height=w, center=(x, y), layer=waveguide_type.cladding_layer)
return insts, elems, ports
这个类定义通过以下方法调用实现版图设计:
library += BendEuler()
library += BendEuler90()
fp.export_gds(library, file=gds_file)
这个类里面定义的仿真可以用于整体链路的仿真。
运行案例，得到的版图文件为:
