diff --git a/birefringence-waveform/waveform.py b/birefringence-waveform/waveform.py
new file mode 100644
index 0000000000000000000000000000000000000000..4cd1a86977004b3636d550493899b3b018ae5f2b
--- /dev/null
+++ b/birefringence-waveform/waveform.py
@@ -0,0 +1,19 @@
+from pycbc.waveform import get_fd_waveform
+import numpy as np
+import pycbc.conversions
+import lal
+
+def IMRPhenomParity(parity_lambdatilt, **kwds):
+
+    if 'approximant' in kwds:
+        kwds.pop("approximant")
+    hp, hc = get_fd_waveform(approximant="IMRPhenomXPHM", **kwds)
+
+    tempVal =  lal.H_SI * lal.PI * lal.PI * r / parity_lambdatilt;
+
+    deltaPhi1 = tempVal * f * f;
+
+    hp_parity = hp + hc * deltaPhi1;
+    hc_parity = hc - hp * deltaPhi1;
+
+    return hpd,hcd