Implementation of passively assembled optical interconnection platform in optical PCMs

Abstract

The architecture of a passively assembled optical platform was suggested for the chip-to-chip optical interconnection system. To demonstrate the optical platform, three components were developed: a fiber-embedded optical printed circuit board (OPCB), 90$\deg$-bent fiber connectors, and optical transmitter/receiver modules. All these components were packaged with precise guide pins and holes so that complete passive alignment was achieved in the OPCB. And, another solution to passively assemble all components on an OPCB was suggested, which was named as ``misalignment absorbing function``. The function is contrasted to the ``self-align function`` and means that it intentionally restricts the self-align function of solder balls using guide pins and holes and absorbs the misalignment in the tilted solder balls. In this paper, the new passive assembly technology is illustrated along the assembly process. Optical losses and optical crosstalk occurred in an optical link were analyzed by a Ray tracing method and a Gaussian optic analysis method. Through the analysis, a misalignment tolerance in the optical loss was obtained and another misalignment tolerance in the optical crosstalk was described. In case of the structure used in this paper, 1-dB misalignment tolerance in the optical loss and misalignment tolerance satisfying $10^{-12}$ bit error rate (BER) in the optical crosstalk are analyzed as $\plusmn$20 $\mum$ and $\plusmn$80 $\mum$, respectively. The simulation results showed enough alignment margins for the fabrication of the architecture by the passive assembly. As above already mentioned, three optical components were illustrated about the design and the fabrication in detail. The features and the fabrication processes of a 1$\times$12 channels fiber- and connector-embedded OPCB, a 1$\times$12 channels 90$\deg$-bent fiber block, and 1$\times$4$\times$10-Gb/s optical modules were described in comparison with other examples. To test optical link exper...