Optical connection with optical pins and self-written waveguides for board-level optical wirings

The potential of optical circuit packaging technology is discussed. Special attention is paid to introduction of "optical wiring" at the printed wiring board level (i.e., in the "last 1 meter area") to overcome the bandwidth limitations of electrical copper-based wiring. The suitability of optical surface mount technology (O-SMT) as a possible solution is reviewed. It is shown that the key to the utility of O-SMT is high efficiency and alignment-free coupling between optical wiring and optical devices. O-SMT requires a method to change the beam direction from the horizontal to the vertical and vice versa in order to couple optical wiring in an OE-board and OE-devices mounted on the board. A novel method using an "optical pin" is proposed and investigated. Furthermore, an optical coupling method using a self-written waveguide called "optical solder" is reviewed. Several applications of self-written waveguides using a green laser and a photo-mask are demonstrated.