The present invention provides an optical printed circuit board blank, comprising, a support layer; one or more optical waveguides formed thereon; and at least one socket for receiving an optical component, the socket including one or more alignment features to ensure alignment of an input/output interface of the said optical component when arranged in the socket with an input/output interface of the at least one waveguide; and a flexible optical connector arranged at an edge of the circuit board, the optical connector being optically connected to the or each of the sockets, to enable optical communication between an optical component located within the or each of the sockets and the optical connector.