diff --git a/src/jax_finufft/ops.py b/src/jax_finufft/ops.py
index 4721c65..65850bc 100644
--- a/src/jax_finufft/ops.py
+++ b/src/jax_finufft/ops.py
@@ -60,6 +60,22 @@ def nufft2(source, *points, iflag=-1, eps=1e-6, opts=None):
     return index.unflatten(result)
 
 
+def get_frequency_array(n, modeord):
+    if modeord == 0:
+        return np.arange(-np.floor(n / 2), np.floor((n - 1) / 2 + 1))
+    elif modeord == 1:
+        if n % 2 == 0:
+            pos = np.arange(0, n // 2)
+            neg = np.arange(-n // 2, 0)
+            return np.concatenate([pos, neg])
+        else:
+            pos = np.arange(0, (n + 1) // 2)
+            neg = np.arange(-(n - 1) // 2, 0)
+            return np.concatenate([pos, neg])
+    else:
+        raise ValueError(f"Unsupported modeord: {modeord}")
+
+
 def jvp(prim, args, tangents, *, output_shape, iflag, eps, opts):
     # Type 1:
     # f_k = sum_j c_j * exp(iflag * i * k * x_j)
@@ -75,6 +91,9 @@ def jvp(prim, args, tangents, *, output_shape, iflag, eps, opts):
         source, *points, output_shape=output_shape, iflag=iflag, eps=eps, opts=opts
     )
 
+    # Extract modeord from opts
+    modeord = opts.modeord if hasattr(opts, "modeord") else 0
+
     # The JVP op can be written as a single transform of the same type with
     output_tangents = []
     ndim = len(points)
@@ -105,7 +124,7 @@ def jvp(prim, args, tangents, *, output_shape, iflag, eps, opts):
         n = source.shape[-ndim + dim] if output_shape is None else output_shape[dim]
         shape = np.ones(ndim, dtype=int)
         shape[dim] = -1
-        k = np.arange(-np.floor(n / 2), np.floor((n - 1) / 2 + 1))
+        k = get_frequency_array(n, modeord)
         k = k.reshape(shape)
         factor = 1j * iflag * k
         dx = dx[:, None, :]