Yes, it is possible. The Splitter makes no difference which Wavelength Division Multiplex method is used. A important notice is, that a CWDM Multiplexer/ Demultiplexer (OCM 18xx) has a high Insertion loss itself. In Combination with a Fiber Splitter like the OSP 1814, which again divides the available budget according to the device, you will need to have a closer look at your available budget therefore.