By using the proposed method, we could improve the utilization of link capacity by 45% compared with the conventional method. An all-optical network based on wavelength division multiplexing (WDM) seems one of promising solutions to this problem since many O/E and E/O converters in the network are eliminated, and it can realize veiy large capacity network by exploiting the advancing transmission technologies. A WDM network, however, exhibits inefficient bandwidth utilization because of its coarse bandw idth granularity. When the amount of traffic between two nodes is not large enough to fill one wavelength capacity, electrical sw itch/routers are often used with WDM nodes for traffic grooming, and thus the pow er consumption is still an issue in the case of carrying many small traffic paths [1], Therefore, an efficient sub-Aswitching with low power consumption is needed.