EMI suppression of 10Gbit/s optical transceiver by using EBG structure

The fiber optic data transmission system plays an important role in broadband communication. According to the market trend, data traffic is significantly increasing and larger throughput of communication systems is required. Many opto-electronic conversion devices (so called optical transceivers) are used in the system. Because of that, the electro-magnetic noise radiation becomes a serious consideration. Although noise level is proportional to the number of transceivers, a qualitative relationship between the number of transceivers and emission level is not clear. Furthermore, since there´s no general design guideline to suppress EMI, it is difficult to solve this problem once it emerges. In these circumstances, recent dispersion control technology such as Electro-magnetic Band Gap (EBG) is a potential solution for this problem. In this paper, the method of how to predict total emission level with the superimposed effect of thousands of transceivers and how to determine the EMI suppression design target are described. Then, the method of how to reach the goal with a newly introduced shielding scheme is described. And, it is demonstrated that the EBG structure is suitable for optical transceivers. Its verification is shown by utilization of FEM/FDTD simulation and an experiment of an in-house prototype.