Abstract: We propose an optical broadcast-and-select network architecture with centralized multi-carrier light source (C-MCLS). It enables all network nodes access a large number of optical carriers in a cost-effective manner through dynamic optical broadcast and select. Cost analysis and numerical results show that it greatly reduces the light source cost compared with the conventional one, as the number of required access wavelengths at network nodes becomes large. We also show its cost-effective areas in different cases of cost calculation. The obtained results indicate that it is very promising for future regional/metro networks, which demand a large number of wavelengths.