In Optical Burst Switching (OBS) networks, Just-in-Time (JIT) is a simple resource reservation scheme, which does not involve complex scheduling and is amenable to hardware implementation. However, in OBS networks using JIT, the header processing time is a main factor that affects the network performance since it is included in resource reservation time. In this paper, we propose a novel optical code (OC)-based header processing with header compression, which is able to reduce the header processing time hence improve the network performance. The numerical results show that OC-based header processing helps to increase the utilization efficiency, reduce the minimum burst length and burst drop probability in comparison with conventional electronic header processing. In addition, we modify the signaling scheme to avoid header swapping at intermediate nodes. Therefore, the complexity of switch nodes can be reduced.