How do I obtain a frequency resolution of 0.1 GHz in my filter definition?

A frequency resolution of 0.1 GHz is supported by every WaveShaper model, provided the filter shape is defined using a .wsp file (and not using the GUI). When creating the .wsp file, just make sure to include an additional digit in the frequency column. As example we create here the .wsp file definition for a channel at 193 THz in a 25 GHz channel spaced system:

192.9874   60            0              0
192.9875   60            0              0
192.9876   0               0              1
192.9877   0               0              1

192.9999   0            0              1
193.0000   0            0              1
193.0001   0            0              1

193.0124   0              0              1
193.0125   0              0              1
193.0126   60           0             0
193.0127   60           0              0

The resulting bandwidth of the channel is 25 GHz.