diff --git a/Project.toml b/Project.toml
index 7bda77a..23135a2 100644
--- a/Project.toml
+++ b/Project.toml
@@ -6,6 +6,7 @@ version = "1.4.0"
 [deps]
 ArgParse = "c7e460c6-2fb9-53a9-8c5b-16f535851c63"
 BandedMatrices = "aae01518-5342-5314-be14-df237901396f"
+DataInterpolations = "82cc6244-b520-54b8-b5a6-8a565e85f1d0"
 FiniteElementHermite = "6ce10167-d368-4c0e-af34-9787cdd175e5"
 ForwardDiff = "f6369f11-7733-5829-9624-2563aa707210"
 JSON = "682c06a0-de6a-54ab-a142-c8b1cf79cde6"
diff --git a/src/QED.jl b/src/QED.jl
index 5c10f12..7e1b93c 100644
--- a/src/QED.jl
+++ b/src/QED.jl
@@ -4,6 +4,7 @@ module QED
 
 using FiniteElementHermite
 using BandedMatrices
+import DataInterpolations
 import ForwardDiff
 import JSON
 using ArgParse
diff --git a/src/build.jl b/src/build.jl
index ddb98d4..441ee68 100644
--- a/src/build.jl
+++ b/src/build.jl
@@ -12,9 +12,9 @@ function Waveform(value::T) where {T<:Real}
 end
 
 # Interpolated waveform
-function Waveform(ts::AbstractVector{T}, values::AbstractVector{S}; order=:cubic) where {T<:Real, S<:Real}
+function Waveform(ts::AbstractVector{T}, values::AbstractVector{S}) where {T<:Real, S<:Real}
     TS = promote_type(T, S)
-    fitp = IMAS.interp1d(ts, values, order)
+    fitp = DataInterpolations.CubicSpline(values, ts; extrapolate=true)
     return Waveform{TS}(t -> fitp(t))
 end