The present invention comprises apparatuses and methods, for routing optical communication signals over all DWDM wavelength channels. Incoming wavelength channels are separated into a plurality of sub-groups having a smaller optical bandwidth. Wavelength channels within each sub-group are then acted upon independently by a filter, or switch, tunable and operable over the bandwidth of each sub-group. The invention may be embodied in a plurality of dynamic wavelength routing circuits including 1.times.N and N.times.N circuits. The 1.times.N circuit embodiments may be used when the filter free-spectral range is smaller than the full DWDM bandwidth. These embodiments are less complicated than the N.times.N circuit embodiments, but do not provide the same routing bandwidth. The N.times.N circuit embodiments may be used to route the full DWDM bandwidth and may be used for other routing operations having large bandwidth demand.