This thesis presents results obtained during the course of my PhD research on optical signal routing and interfacing between the metropolitan and access segments of optical networks. Due to both increasing capacity demands and variety of emerging services types, new technological challenges are arising for seamlessly interfacing metropolitan and access networks. Therefore, in this PhD project, I have analyzed those technological challenges and identified the key aspects to be addressed. I have also proposed and experimentally verified a number of solutions to metropolitan and access networks interfacing and signal routing. Equipment and infrastructure simplification was recognized as the path towards more efficient metropolitan and access networks providing a spectrum of high-bandwidth services to large number of users. Several approaches have been proposed and developed in order to enable such simplification, including architectural solutions like fusion of metropolitan and access networks, service broadcasting and distribution of wireless signals over common fiber infrastructure; and physical layer solutions like introducing colorless operation for metropolitan network nodes and gain transient control. Highlights of my research include my proposal and experimental proof of principle of an optical coherent detection based optical access network architecture providing support for a large number of users over a single distribution fiber; a spectral amplitude encoded label detection technique for metropolitan and access signal routing and the incorporation of both wireless and wireline signal transmission for extended reach converged metropolitan access networks.