small noise improvements

pyproject.toml

@@ -4,7 +4,7 @@ build-backend = "setuptools.build_meta"
 
 [project]
 name = "scgenerator"
-version = "0.3.24"
+version = "0.3.25"
 description = "Simulate nonlinear pulse propagation in optical fibers"
 readme = "README.md"
 authors = [{ name = "Benoit Sierro", email = "benoit.sierro@iap.unibe.ch" }]

src/scgenerator/noise.py

@@ -217,6 +217,8 @@ class NoiseMeasurement:
         spec[1:-1] *= 0.5
         if phase is None:
             phase = 2 * np.pi * self.rng.random(len(freq) - 2)
+        elif phase.shape[-1] != len(freq) - 2:
+            phase = np.interp(freq, self.freq, phase)[1:-1]
         time, dt = math.irfftfreq(freq, True)
 
         amp = np.asarray(np.sqrt(spec), dtype=complex)

src/scgenerator/physics/pulse.py

@@ -545,11 +545,11 @@ def shot_noise(w: np.ndarray, dt: float):
     dw = w[1] - w[0]
 
     rand_phase = np.random.rand(len(w)) * 2 * pi
-    oppm_phase = np.exp(-1j * rand_phase)
+    shot_noise_phase = np.exp(-1j * rand_phase)
 
-    oppm_amp = np.sqrt(0.5 * units.hbar * np.abs(w) / dw)
+    shot_noise_amplitude = np.sqrt(0.5 * units.hbar * np.abs(w) / dw)
 
-    return ifft(oppm_amp * oppm_phase / dt * np.sqrt(2 * pi))
+    return ifft(shot_noise_amplitude * shot_noise_phase / dt * np.sqrt(2 * pi))
 
 
 def finalize_pulse(
@@ -614,7 +614,29 @@ def compress_pulse(spectra: np.ndarray):
     else:
         return fftshift(ifft(flatten_phase(spectra)), axes=1)
 
+def shot_noise(w: np.ndarray, dt: float):
+    """
 
+    Parameters
+    ----------
+    w : array, shape (n,)
+        angular frequencies
+    dt : float
+        resolution of time grid
+
+    Returns
+    -------
+    np.ndarray, shape (n,)
+        noise field to be added on top of initial field in time domain
+    """
+    dw = w[1] - w[0]
+
+    rand_phase = np.random.rand(len(w)) * 2 * pi
+    shot_noise_phase = np.exp(-1j * rand_phase)
+
+    shot_noise_amplitude = np.sqrt(0.5 * units.hbar * np.abs(w) / dw)
+
+    return ifft(shot_noise_amplitude * shot_noise_phase / dt * np.sqrt(2 * pi))
 def ideal_compressed_pulse(spectra: np.ndarray):
     """
     returns the ideal compressed pulse assuming flat phase

src/scgenerator/physics/units.py

@@ -375,14 +375,26 @@ def nm_rads(nm: _T) -> _T:
     return 2e9 * np.pi * c / nm
 
 
+def nm_hz(nm: _T) -> _T:
+    return 1e9 * c / nm
+
+
 def um_rads(um: _T) -> _T:
     return 2e6 * np.pi * c / um
 
 
+def um_hz(um: _T) -> _T:
+    return 1e6 * c / um
+
+
 def m_rads(m: _T) -> _T:
     return 2 * np.pi * c / m
 
 
+def m_hz(m: _T) -> _T:
+    return c / m
+
+
 def get_unit(unit: Union[str, Callable]) -> Callable[[float], float]:
     if isinstance(unit, str):
         return units_map[unit]