Multi-band Coherent Optical OFDM (MB CO-OFDM) is widely predicted to be one of the technologies which will empower 100 Gigabit Ethernet (100GbE) networks. CO-OFDM uses coherent technology and advanced digital signal processing (DSP) to achieve net data rate of 10 Gbps in a single band. This strict throughput requirement puts a constraint on the kind of signal processing algorithms and architectures used for building the system. In this paper, a scalable parallel architecture using radix-2$^{2}$ for IFFT is proposed. The second proposal consists of a scalable parallel timing synchronization algorithm which can support very high input rates at the receiver. MOPS count as well as area versus throughput for the synchronization algorithm are provided for the OFDM transceiver to show the improvements due to proposed architecture. Architecture exploration is done using a leading-edge high-level synthesis (HLS) tool.