improve mmis for rib waveguides

gdsfactory/components/mmi.py

@@ -2,7 +2,6 @@
 
 import gdsfactory as gf
 from gdsfactory.component import Component
-from gdsfactory.components.straight import straight as straight_function
 from gdsfactory.components.taper import taper as taper_function
 from gdsfactory.typings import Callable, ComponentFactory, CrossSectionSpec
 
@@ -19,7 +18,6 @@ def mmi(
     gap_input_tapers: float = 0.25,
     gap_output_tapers: float = 0.25,
     taper: ComponentFactory = taper_function,
-    straight: ComponentFactory = straight_function,
     cross_section: CrossSectionSpec = "xs_sc",
     input_positions: list[float] | None = None,
     output_positions: list[float] | None = None,
@@ -38,7 +36,6 @@ def mmi(
         gap_input_tapers: gap between input tapers from edge to edge.
         gap_output_tapers: gap between output tapers from edge to edge.
         taper: taper function.
-        straight: straight function.
         cross_section: specification (CrossSection, string or dict).
         input_positions: optional positions of the inputs.
         output_positions: optional positions of the outputs.
@@ -65,11 +62,10 @@ def mmi(
     c = Component()
     gap_input_tapers = gf.snap.snap_to_grid(gap_input_tapers, grid_factor=2)
     gap_output_tapers = gf.snap.snap_to_grid(gap_output_tapers, grid_factor=2)
-    w_mmi = width_mmi
     w_taper = width_taper
     x = gf.get_cross_section(cross_section)
-    xs_mmi = gf.get_cross_section(cross_section, width=w_mmi)
     width = width or x.width
+    delta_width = width_mmi - width
 
     _taper = taper(
         length=length_taper,
@@ -79,7 +75,20 @@ def mmi(
         add_pins=False,
     )
 
-    mmi = c << straight(length=length_mmi, cross_section=xs_mmi, add_pins=False)
+    y = width_mmi / 2
+    c.add_polygon([(0, -y), (length_mmi, -y), (length_mmi, y), (0, y)], layer=x.layer)
+    for section in x.sections[1:]:
+        layer = section.layer
+        y = section.width / 2 + delta_width / 2
+        c.add_polygon(
+            [
+                (-delta_width, -y),
+                (length_mmi + delta_width, -y),
+                (length_mmi + delta_width, y),
+                (-delta_width, y),
+            ],
+            layer=layer,
+        )
 
     wg_spacing_input = gap_input_tapers + width_taper
     wg_spacing_output = gap_output_tapers + width_taper
@@ -124,11 +133,10 @@ def mmi(
         c.add_port(name=port.name, port=taper_ref.ports["o1"])
         c.absorb(taper_ref)
 
-    c.absorb(mmi)
     if x.add_bbox:
-        c = x.add_bbox(c)
+        x.add_bbox(c)
     if x.add_pins:
-        c = x.add_pins(c)
+        x.add_pins(c)
     c.auto_rename_ports()
     if post_process:
         post_process(c)
@@ -138,6 +146,7 @@ def mmi(
 if __name__ == "__main__":
     # import gdsfactory as gf
     # c = gf.components.mmi1x2(cross_section="xs_rc")
-    c = mmi(inputs=2, outputs=4, gap_input_tapers=0.5, input_positions=[-1, 1])
-    print(len(c.ports))
+    # c = mmi(inputs=2, outputs=4, gap_input_tapers=0.5, input_positions=[-1, 1])
+    c = mmi(cross_section="xs_rc")
+    # print(len(c.ports))
     c.show(show_ports=True)

gdsfactory/components/mmi1x2.py

@@ -62,7 +62,6 @@ def mmi1x2(
     c = Component()
     gap_mmi = gf.snap.snap_to_grid(gap_mmi, grid_factor=2)
     x = gf.get_cross_section(cross_section, **kwargs)
-    xs_mmi = gf.get_cross_section(cross_section, width=width_mmi)
     width = width or x.width
 
     _taper = taper(
@@ -73,9 +72,23 @@ def mmi1x2(
         add_pins=False,
     )
 
-    a = gap_mmi / 2 + width_taper / 2
-    mmi = c << straight(length=length_mmi, cross_section=xs_mmi, add_pins=False)
+    delta_width = width_mmi - width
+    y = width_mmi / 2
+    c.add_polygon([(0, -y), (length_mmi, -y), (length_mmi, y), (0, y)], layer=x.layer)
+    for section in x.sections[1:]:
+        layer = section.layer
+        y = section.width / 2 + delta_width / 2
+        c.add_polygon(
+            [
+                (-delta_width, -y),
+                (length_mmi + delta_width, -y),
+                (length_mmi + delta_width, y),
+                (-delta_width, y),
+            ],
+            layer=layer,
+        )
 
+    a = gap_mmi / 2 + width_taper / 2
     ports = [
         gf.Port(
             "o1",
@@ -109,7 +122,6 @@ def mmi1x2(
         c.add_port(name=port.name, port=taper_ref.ports["o1"])
         c.absorb(taper_ref)
 
-    c.absorb(mmi)
     if with_bbox:
         x.add_bbox(c)
     if x.add_pins:

gdsfactory/components/mmi2x2.py

@@ -63,7 +63,6 @@ def mmi2x2(
     gap_mmi = gf.snap.snap_to_grid(gap_mmi, grid_factor=2)
     w_taper = width_taper
     x = gf.get_cross_section(cross_section, **kwargs)
-    xs_mmi = gf.get_cross_section(cross_section, width=width_mmi)
     width = width or x.width
 
     _taper = taper(
@@ -74,9 +73,23 @@ def mmi2x2(
         add_pins=False,
     )
 
-    a = gap_mmi / 2 + width_taper / 2
-    mmi = c << straight(length=length_mmi, cross_section=xs_mmi, add_pins=False)
+    delta_width = width_mmi - width
+    y = width_mmi / 2
+    c.add_polygon([(0, -y), (length_mmi, -y), (length_mmi, y), (0, y)], layer=x.layer)
+    for section in x.sections[1:]:
+        layer = section.layer
+        y = section.width / 2 + delta_width / 2
+        c.add_polygon(
+            [
+                (-delta_width, -y),
+                (length_mmi + delta_width, -y),
+                (length_mmi + delta_width, y),
+                (-delta_width, y),
+            ],
+            layer=layer,
+        )
 
+    a = gap_mmi / 2 + width_taper / 2
     ports = [
         gf.Port("o1", orientation=180, center=(0, -a), width=w_taper, cross_section=x),
         gf.Port("o2", orientation=180, center=(0, +a), width=w_taper, cross_section=x),
@@ -102,7 +115,6 @@ def mmi2x2(
         c.add_port(name=port.name, port=taper_ref.ports["o1"])
         c.absorb(taper_ref)
 
-    c.absorb(mmi)
     if with_bbox:
         x.add_bbox(c)
     if x.add_pins:
@@ -114,6 +126,6 @@ def mmi2x2(
 
 if __name__ == "__main__":
     # c = mmi2x2(gap_mmi=0.252, cross_section="xs_m1")
-    c = mmi2x2(gap_mmi=0.252)
+    c = mmi2x2(gap_mmi=0.252, cross_section="xs_rc")
     c.show(show_ports=True)
     c.pprint()