This paper presents solutions towards an efficient and intelligent network infrastructure for Grid services, taking advantage of recent developments in optical-networking technologies. Two lambda-Grid network architectures based on extensions to existing wavelength-switched network infrastructure are discussed. These network solutions aim to provide a user-centric Grid environment, specifically for data-intensive and e-science applications. Furthermore, a novel solution towards an intelligent and ubiquitous photonic-Grid network based on optical burst switching (OBS) is proposed. The proposed solution utilizes active optical burst-switched routers and advanced protocols in order to provide a programmable photonic-Grid network infrastructure for evolving data-intensive and emerging Grid applications.