Wavelength cross connect device, branch ratio variable method, and program

Abstract

A large number of degrees for relays of optical signals transmitted via optical paths in the degrees is secured. A wavelength cross-connect deviceA performs a relay by splitting optical signals from respective degrees indicated by reference numerals, each of the degrees being provided by optical fibers, via respective optical couplers and outputting the split optical signals to output sides of the plurality of degrees via respective WSSsto. As the optical couplers, variable couplerstowhose respective splitting ratios, each of which is a ratio of optical signal power losses in splitting an optical signal, are variable are used. The wavelength cross-connect deviceA includes a control unitthat performs control to change the splitting ratios in such a manner as to eliminate an imbalance among OSNR margins of the output sides of the degrees in which a plurality of optical paths transmitting the split optical signals extend. The control unitcalculates the margins for the respective optical paths transmitting the split optical signals via the variable couplersto, for each of the output sides of the degrees. The control unitperforms control to, based on respective smallest margins of the degrees in all the margins, change the splitting ratios of the variable couplerstoin such a manner as to eliminate an imbalance between the margins of the degrees.