In order to address a diverse and demanding set of service and network drivers, several technology candidates with inherent physical layer (PHY) differences are emerging for future optical access networks. To overcome this PHY divide and enable both cost and bandwidth efficient heterogeneous technology co-existence in future optical access, we propose a novel Orthogonal Frequency Division Multiple Access (OFDMA)-based “meta-MAC”, which encapsulates PHY variations and enables fair inter-technology bandwidth arbitration. The new software-defined meta-MAC is envisioned to work on top of constituent MAC protocols, and exploit virtual OFDMA subcarriers as both finely granular and scalable bandwidth assignment units. We introduce important OFDMA meta-MAC design principles, and propose an elaborate three-stage dynamic resource provisioning scheme that satisfies the key requirements. The performance benefits of the meta-MAC concept and the proposed dynamic resource provisioning schemes in terms of spectrum management flexibility and support of diverse services are verified via real-time traffic simulation, confirming the attractiveness of the new approach for future optical access systems.