diff --git a/src/scgenerator/parameter.py b/src/scgenerator/parameter.py
index 55331fc..097b39e 100644
--- a/src/scgenerator/parameter.py
+++ b/src/scgenerator/parameter.py
@@ -361,7 +361,7 @@ class Parameters:
     shape: str = Parameter(literal("gaussian", "sech"))
     wavelength: float = Parameter(in_range_incl(100e-9, 10000e-9), unit="m")
     intensity_noise: float = Parameter(in_range_incl(0, 1), unit="%")
-    ase_level: float = Parameter(positive(*number), default=1.0)
+    ase_level: float = Parameter(non_negative(*number))
     noise_correlation: float = Parameter(in_range_incl(-10, 10))
     width: float = Parameter(positive(*number), unit="s")
     t0: float = Parameter(positive(*number), unit="s")