Merge pull request #292 from Hang-Bobby-Zou/master

Create EBeam_GC_SiN_1310_8deg.py

klayout/EBeam/pymacros/pcells_SiN/EBeam_GC_SiN_1310_8deg.py

@@ -0,0 +1,307 @@
+from pya import *
+import pya
+
+def linspace_without_numpy(low, high, length):
+    step = ((high-low) * 1.0 / length)
+    return [low+i*step for i in range(length)]
+
+class EBeam_GC_SiN_1310_8deg(pya.PCellDeclarationHelper):
+  """
+  Universal Grating Coupler PCell implementation.
+  Analytical design based on "Grating Coupler Design Based on Silicon-On-Insulator", Yun Wang (2013). Master's Thesis, University of British Columbia, Canada
+  Some PCell implementation adapted from the SiEPIC_EBeam library by Dr. Lukas Chrostowski, University of British Columbia, Canada
+  Orignal script written by Timothy Richards (Simon Fraser University, BC, Canada) and Adam DeAbreu (Simon Fraser University, BC, Canada)
+  Modified to use UGC method presented in : Yun Wang, Jonas Flueckiger, Charlie Lin, Lukas Chrostowski, "Universal grating coupler design," Proc. SPIE 8915, Photonics North 2013, 89150Y (11 October 2013), 
+  Transfered from Mentor Graphics to KLayout by Connor Mosquera (University of British Columbia, Canada)
+  
+  """
+
+  def __init__(self):
+
+    # Important: initialize the super class
+    super(EBeam_GC_SiN_1310_8deg, self).__init__()
+    from SiEPIC.utils import get_technology_by_name, load_Waveguides_by_Tech
+    TECHNOLOGY = get_technology_by_name('EBeam')
+    self.TECHNOLOGY = TECHNOLOGY
+
+    # declare the parameters  
+    self.param("wavelength", self.TypeDouble, "Design Wavelength (micron)", default = 1.31)  
+    self.param("Si_thickness", self.TypeDouble, "SiN Thickness (micron)", default = 0.4)
+    self.param("etch_depth", self.TypeDouble, "Etch Depth (micron)", default = 0.4, hidden = True)
+    self.param("pol", self.TypeString, "Polarization", default = "TE")
+    self.param("n_t", self.TypeDouble, "Cladding Index", default = 1.4223)
+    self.param("angle_e", self.TypeDouble, "Taper Angle (deg)", default = 36.0)
+    self.param("grating_length", self.TypeDouble, "Grating Length (micron)", default = 30.0)
+    self.param("taper_length", self.TypeDouble, "Taper Length (micron)", default = 20)
+    self.param("dc", self.TypeDouble, "Duty Cylce", default = 0.5)
+    self.param('pitch', self.TypeDouble, "Pitch (micron)", default = 1)
+    self.param("t", self.TypeDouble, "Waveguide Width (micron)", default = 0.75)
+    self.param("theta_c", self.TypeDouble, "Insertion Angle (deg)", default = 8.0)
+
+    # Layer parameters
+    self.param("layer", self.TypeLayer, "Layer", default = TECHNOLOGY['SiN'])
+    self.param("pinrec", self.TypeLayer, "PinRec Layer", default = TECHNOLOGY['PinRec'])
+    self.param("devrec", self.TypeLayer, "DevRec Layer", default = TECHNOLOGY['DevRec'])
+
+  def display_text_impl(self):
+    # Provide a descriptive text for the cell
+    return "Universal_GC_%.1f-%.2f-%.2f-%.2f-%.2f-%.2f" % \
+    (self.wavelength, self.theta_c, self.dc, self.angle_e, self.taper_length, self.t)
+
+#    return "temporary placeholder"
+
+  def coerce_parameters_impl(self):
+    pass
+
+  def can_create_from_shape(self, layout, shape, layer):
+    return False
+
+  def produce_impl(self):
+    # fetch the parameters
+    dbu = self.layout.dbu
+    ly = self.layout
+    shapes = self.cell.shapes
+    TECHNOLOGY = self.TECHNOLOGY
+
+    LayerSi = self.layer
+    LayerSiN = ly.layer(LayerSi)
+    LayerSiSPN = ly.layer(LayerSi)
+    LayerPinRecN = ly.layer(self.pinrec)
+    LayerDevRecN = ly.layer(self.devrec)
+    LayerTextN = TECHNOLOGY['Text']
+
+    ######## effective index function ##########
+
+    def effective_index(wl = self.wavelength, etch_depth = self.etch_depth, Si_thickness = self.Si_thickness, n_t = self.n_t, pol = self.pol, dc = self.dc):
+
+      from math import pi, cos, sin, log, sqrt, tan
+      from SiEPIC.utils import points_per_circle
+
+      point =1001
+      n_0 = n_t
+      n_1 = 0
+      n_3 = 1.4223
+      #if 0:  # Silicon
+      #    n_2 = sqrt(7.9874+(3.68*pow(3.9328,2)*pow(10,30))/((pow(3.9328,2)*pow(10,30)-pow(2*3.14*3*pow(10,8)/(wl*pow(10,-6)),2))))  # Silicon wavelength-dependant index of refraction
+      #if 1:  # Silicon Nitride
+      n_2 = 2.0031  # approximate  
+      delta = n_0 - n_3 
+      t = Si_thickness
+      t_slot = t - etch_depth
+      k_0 = 2*pi/wl
+
+      b_0 = linspace_without_numpy(0, 0, point-1)
+      te_0 = linspace_without_numpy(0, 0, point-1)
+      te_1 = linspace_without_numpy(0, 0, point-1)
+      tm_0 = linspace_without_numpy(0, 0, point-1)
+      tm_1 = linspace_without_numpy(0, 0, point-1)
+      h_0 = linspace_without_numpy(0, 0, point-1)
+      q_0 = linspace_without_numpy(0, 0, point-1)
+      p_0 = linspace_without_numpy(0, 0, point-1)
+      qbar_0 = linspace_without_numpy(0, 0, point-1)
+      pbar_0 = linspace_without_numpy(0, 0, point-1)
+
+      # calculating neff for the silicon layer
+      if delta<0:
+        n_1 = n_3
+      else:
+        n_1 = n_0
+
+      for ii in range(0,point-1):
+        b_0[ii] = n_1*k_0 + (n_2 - n_1)*k_0/(point-1)*ii   # copied from .ample UGC: should this be point-1?
+
+        h_0[ii] = sqrt( abs(pow(n_2*k_0,2) - pow(b_0[ii],2)));	
+        q_0[ii] = sqrt( abs(pow(b_0[ii],2) - pow(n_0*k_0,2)));
+        p_0[ii] = sqrt( abs(pow(b_0[ii],2) - pow(n_3*k_0,2)));
+
+        pbar_0[ii] = pow(n_2/n_3, 2)*p_0[ii]
+        qbar_0[ii] = pow(n_2/n_0, 2)*q_0[ii]
+
+      # calculating neff for TE mode
+      if pol == "TE":
+        for ii in range(0, point-1):
+          te_0[ii] =  tan( h_0[ii]*t )-(p_0[ii]+q_0[ii])/h_0[ii]/(1-p_0[ii]*q_0[ii]/pow(h_0[ii],2)) 
+          te_1[ii] =  tan( h_0[ii]*t_slot )-(p_0[ii]+q_0[ii])/h_0[ii]/(1-p_0[ii]*q_0[ii]/pow(h_0[ii],2))
+
+        abs_te_0 = [abs(x) for x in te_0] 
+        abs_te_1 = [abs(x) for x in te_1] 
+        index_TE_0 = abs_te_0.index(min(abs_te_0))
+        index_TE_1 = abs_te_1.index(min(abs_te_1))
+        nTE_0 = b_0[index_TE_0]/k_0
+        nTE_1 = b_0[index_TE_1]/k_0
+        nTE_1 = n_3
+
+        while (nTE_0<1.5 or nTE_0>3):
+          abs_te_0[index_TE_0] = 100
+          index_TE_0 = abs_te_0.index(min(abs_te_0))
+          nTE_0 = b_0[index_TE_0]/k_0
+
+        '''  
+        while (nTE_1<1.5 or nTE_1>3):
+          abs_te_1[index_TE_1] = 100
+          index_TE_1 = abs_te_1.index(min(abs_te_1))
+          nTE_1 = b_0[index_TE_1]/k_0
+        '''
+
+        ne=dc*nTE_0+(1-dc)*nTE_1
+
+      # calculating neff for TE mode
+      elif pol == "TM":
+        for ii in range(0, point-1):
+          tm_0[ii] =  tan( h_0[ii]*t )-(pbar_0[ii]+qbar_0[ii])/h_0[ii]/(1-pbar_0[ii]*qbar_0[ii]/pow(h_0[ii],2)) 
+          tm_1[ii] =  tan( h_0[ii]*t_slot )-(pbar_0[ii]+qbar_0[ii])/h_0[ii]/(1-pbar_0[ii]*qbar_0[ii]/pow(h_0[ii],2))
+
+        abs_tm_0 = [abs(x) for x in tm_0] 
+        abs_tm_1 = [abs(x) for x in tm_1] 
+        index_TM_0 = abs_tm_0.index(min(abs_tm_0))
+        index_TM_1 = abs_tm_1.index(min(abs_tm_1))
+        nTM_0 = b_0[index_TM_0]/k_0
+        nTM_1 = b_0[index_TM_1]/k_0
+
+        while (nTM_0<1.5 or nTM_0>3):
+          abs_tm_0[index_TM_0] = 100
+          index_TM_0 = abs_tm_0.index(min(abs_tm_0))
+          nTM_0 = b_0[index_TM_0]/k_0
+
+        while (nTM_1<1.5 or nTM_1>3):
+          abs_tm_1[index_TM_1] = 100
+          index_TM_1 = abs_tm_1.index(min(abs_tm_1))
+          nTM_1 = b_0[index_TM_1]/k_0
+
+        ne=dc*nTM_0+(1-dc)*nTM_1
+
+      else:
+        print('Please type TE or TM for polarization')
+
+      return ne
+    #####################################
+
+    from math import pi, cos, sin, log, sqrt, tan
+    from SiEPIC.utils import points_per_circle
+
+    lambda_0 = self.wavelength                   ##um wavelength of light
+
+    n_e = effective_index()
+    ne_fiber = 1 # effective index of the mode in the air
+    period = self.wavelength/(n_e - sin(pi/180*self.theta_c)*ne_fiber)
+    period = self.pitch
+
+
+    # Geometry
+    wh = period*self.dc                   ##thick grating
+
+    gc_number = int(round(self.grating_length/period)) ##number of periods by dividing the defined length and rounding it
+    e = self.n_t*sin((pi/180)*self.theta_c)/n_e
+    N = round(self.taper_length*(1+e)*n_e/lambda_0) ##allows room for the taper
+
+    start = (pi - (pi/180)*self.angle_e/2)
+    stop = (pi + (pi/180)*self.angle_e/2)
+
+    # Draw coupler grating.
+    for j in range(gc_number):
+
+        # number of points in the arcs:
+        # calculate such that the vertex & edge placement error is < 0.5 nm.
+        #   see "SiEPIC_EBeam_functions - points_per_circle" for more details
+        radius = N*lambda_0 / (n_e*( 1 - e )) + j*period
+        seg_points = int(points_per_circle(radius/dbu, dbu=dbu)/360.*self.angle_e) # number of points grating arc
+        theta_up = []
+        for m in range(seg_points+1):    
+          theta_up = theta_up + [start + m*(stop-start)/seg_points]
+        theta_down = theta_up[::-1]
+
+        ##big one
+        r_up = []
+        r_down = []
+        for k in range(len(theta_up)):
+          r_up = r_up + [N*lambda_0 / (n_e*( 1 - e*cos(float(theta_up[k])) )) + j*period+period*(1-self.dc)]
+        r_down = r_up[::-1]
+
+        xr = []
+        yr = []
+        for k in range(len(theta_up)):
+          xr = xr + [r_up[k]*cos(theta_up[k])]
+          yr = yr + [r_up[k]*sin(theta_up[k])]
+
+        xl = []
+        yl = []
+        for k in range(len(theta_down)):
+          xl = xl + [(r_down[k] + wh)*cos(theta_down[k])]
+          yl = yl + [(r_down[k] + wh)*sin(theta_down[k])]
+
+        x = xr + xl
+        y = yr + yl
+
+        pts = []
+        for i in range(len(x)):
+            pts.append(Point.from_dpoint(DPoint(x[i]/dbu, y[i]/dbu)))
+
+        polygon = Polygon(pts)
+        shapes(LayerSiN).insert(polygon)
+
+    # Taper section
+    r_up = []
+    r_down = []
+    for k in range(len(theta_up)):  
+      r_up = r_up + [N*lambda_0 / (n_e*( 1 - e*cos(float(theta_up[k])) ))]
+    r_down = r_up[::-1]
+
+    xl = []
+    yl = []  
+    for k in range(len(theta_down)):
+      xl = xl + [(r_down[k])*cos(theta_down[k])]
+      yl = yl + [(r_down[k])*sin(theta_down[k])]
+
+    yr = [self.t/2., -self.t/2.]
+
+    yl_abs = []
+    for k in range(len(yl)):
+      yl_abs = yl_abs + [abs(yl[k])]
+
+    y_max = max(yl_abs)
+    iy_max = yl_abs.index(y_max)
+
+    L_o = (y_max - self.t/2)/tan((pi/180)*self.angle_e/2)
+
+    xr = [0, 0]
+
+    x = xr + xl
+    y = yr + yl  
+
+    pts = []
+    for i in range(len(x)):
+      pts.append(Point.from_dpoint(DPoint(x[i]/dbu, y[i]/dbu)))
+
+    polygon = Polygon(pts)
+    shapes(LayerSiN).insert(polygon)
+
+
+    # Pin on the waveguide:
+    from SiEPIC._globals import PIN_LENGTH as pin_length
+    x = 0
+    t = Trans(Trans.R0, x,0)
+    pin = Path([Point(-pin_length/2,0), Point(pin_length/2,0)], self.t/dbu)
+    pin_t = pin.transformed(t)
+    shapes(LayerPinRecN).insert(pin_t)
+    text = Text ("pin1", t)
+    shape = shapes(LayerPinRecN).insert(text)
+    shape.text_size = 0.4/dbu
+
+    # Reference information
+    t = Trans(Trans.R0, 0,-4000)
+    text = Text ("Ref: 'Universal grating coupler design'\nhttps://doi.org/10.1117/12.2042185\nPCell implementation by: Yun Wang, Timothy Richards, Adam DeAbreu,\nJonas Flueckiger, Charlie Lin, Lukas Chrostowski, Connor Mosquera\n Adapted by Hang Bobby Zou", t)
+    shape = shapes(LayerPinRecN).insert(text)
+    shape.text_size = 0.4/dbu
+    shape.text_halign=2 # right alignment
+
+    t = Trans(Trans.R0, 0,4000)
+    text = Text ("Wavelength: %s\nIncident Angle: %s\nPolarization: %s\nSilicon thickness: %s\nSilicon etch depth: %s\nRadius: %s" % (self.wavelength, self.theta_c, self.pol, self.Si_thickness, self.etch_depth, radius), t)
+    shape = shapes(LayerPinRecN).insert(text)
+    shape.text_size = 0.4/dbu
+    shape.text_halign=2 # right alignment
+    shape.text_valign=2 # bottom alignment
+
+    # Device recognition layer 
+    yr = sin(start) * (N*lambda_0 / ( n_e*( 1 - e*cos(float(start)) )) + gc_number*period )
+    box1 = Box(-(self.grating_length+self.taper_length)/dbu-pin_length*2, yr/dbu, 0, -yr/dbu)
+    shapes(LayerDevRecN).insert(box1)