From f81a1becc4d6cc9c4cbfeca52a5e6ced45279163 Mon Sep 17 00:00:00 2001
From: Lukas Chrostowski <lukasc@ece.ubc.ca>
Date: Tue, 29 Oct 2024 23:37:10 -0700
Subject: [PATCH 1/2] Update spiral_paperclip.py

putting the spiral middle (where it switches from CW to CCW), on one side, to reduce the number of SM to MM converters (two fewer). Thanks Pegah at UBC.
---
 .../pcells_EBeam_Beta/spiral_paperclip.py      | 18 ++++++++++++++++--
 1 file changed, 16 insertions(+), 2 deletions(-)

diff --git a/klayout/EBeam/pymacros/pcells_EBeam_Beta/spiral_paperclip.py b/klayout/EBeam/pymacros/pcells_EBeam_Beta/spiral_paperclip.py
index 600ac943..df6bc6c9 100644
--- a/klayout/EBeam/pymacros/pcells_EBeam_Beta/spiral_paperclip.py
+++ b/klayout/EBeam/pymacros/pcells_EBeam_Beta/spiral_paperclip.py
@@ -290,8 +290,8 @@ def produce_impl(self):
         # spiral points
         points = [
             DPoint(-length0, offset),
-            DPoint(0.0, offset),
-            DPoint(0.0, -offset),
+            DPoint(-length0+radius*2, offset),
+            DPoint(-length0+radius*2, -offset),
             DPoint(length0, -offset),
         ]
         for i in range(1, self.loops * 2, 2):
@@ -447,6 +447,11 @@ def __init__(self):
     from SiEPIC.utils.layout import new_layout
     from SiEPIC.scripts import zoom_out
 
+    from SiEPIC._globals import Python_Env
+    if Python_Env == 'Script':
+        # For external Python mode, when installed using pip install siepic_ebeam_pdk
+        import siepic_ebeam_pdk
+
     # load the test library, and technology
     t = test_lib()
     tech = t.technology
@@ -505,3 +510,12 @@ def __init__(self):
                 xmax = max(xmax, x + inst.bbox().width())
 
     zoom_out(topcell)
+
+
+    # Display the layout in KLayout, using KLayout Package "klive", which needs to be installed in the KLayout Application
+    if Python_Env == 'Script':
+        from SiEPIC.scripts import export_layout
+        path = os.path.dirname(os.path.realpath(__file__))
+        file_out = export_layout (topcell, path, filename='spiral_paperclip', relative_path='', format='oas')
+        from SiEPIC.utils import klive
+        klive.show(file_out, technology=tech)

From e411887a702a82a68f2dfdcdfe1c6d80590f323d Mon Sep 17 00:00:00 2001
From: Lukas Chrostowski <lukasc@ece.ubc.ca>
Date: Tue, 29 Oct 2024 23:39:10 -0700
Subject: [PATCH 2/2] Update WAVEGUIDES_SiN.xml
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

SiN with 50 µm bend radius and bezier parameters.
@jingxiang would you be able to optimize the bends for the standard SiN process? 1310, 1550 nm?  There are different waveguide widths as well, so wondering what is a good choice. thanks!
---
 klayout/EBeam/WAVEGUIDES_SiN.xml | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/klayout/EBeam/WAVEGUIDES_SiN.xml b/klayout/EBeam/WAVEGUIDES_SiN.xml
index 1a2ebf04..7e4431a7 100755
--- a/klayout/EBeam/WAVEGUIDES_SiN.xml
+++ b/klayout/EBeam/WAVEGUIDES_SiN.xml
@@ -129,7 +129,8 @@
   <CML>None</CML>
   <model>None</model>
   <sbends>true</sbends>
-  <radius>110</radius>
+  <bezier>0.3</bezier>
+  <radius>50.0</radius>
   <width>0.75</width>
   <component>
     <layer>SiN</layer>