diff --git a/thewalrus/symplectic.py b/thewalrus/symplectic.py
index 19a1ccfd8..6e698340c 100644
--- a/thewalrus/symplectic.py
+++ b/thewalrus/symplectic.py
@@ -279,4 +279,4 @@ def rotation(theta):
         array: rotation matrix by angle theta
     """
     V = np.identity(1) * np.exp(1j * theta)
-    return V
+    return interferometer(V)
diff --git a/thewalrus/tests/test_symplectic.py b/thewalrus/tests/test_symplectic.py
index e6a8c3d78..c5c9f11b5 100644
--- a/thewalrus/tests/test_symplectic.py
+++ b/thewalrus/tests/test_symplectic.py
@@ -175,9 +175,8 @@ def test_beamsplitter(self, tol):
     def test_rotation(self, tol):
         """Test that a rotation returns the correct symplectic for an abritrary angle"""
         theta = 0.98
-        U = symplectic.rotation(theta)
-        S = symplectic.interferometer(U)
-        expected = np.block([[U.real, -U.imag], [U.imag, U.real]])
+        S = symplectic.rotation(theta)
+        expected = np.block([[np.cos(theta), -np.sin(theta)], [np.sin(theta), np.cos(theta)]])
         np.allclose(S, expected, atol=tol, rtol=0)