IEC TR 62658-2013 pdf Roadmap of optical circuit boards and their related packaging technologies

2.3 Planar embedded optical waveguides It is proposed that the resulting performance bottleneck due to the electrical constraints described above be substantially reduced by conveying high-speed data optically instead of electronically. This requires that optical channels be incorporated into the system at the printed circuit board (PCB) level. While many technology solutions have been put forward and commercially deployed to support embedding conventional optical fibres onto printed circuit boards, there has been a great deal of research and development activity centred in Europe looking at the fabrication and deployment of planar optical waveguide channels on/ in printed circuit board substrates[1 0] to [1 8]. The key academic contributors to research into planar optical waveguides include University of Cambridge, University College London, Vrije Universitaet Brussels, University of Ghent, Loughborough University, Heriot-Watt University and Fraunhofer Institute IZM, while the key industrial contributors include IBM Research in Zürich, Xyratex Technology, TTM Technologies, Vario-optics, TE Connectivity, FCI and Dow Corning. Collectively research and development activities in this field have included a wide range of planar waveguide fabrication techniques, in-plane and out-of-plane waveguide coupling and connector solutions. Though this activity has been mostly centred on polymer waveguides, some research and development has been carried out on embedded planar glass waveguides as well. 3 Standardization of board-level optical packaging 3.1 Role of IEC TC86/JWG9 (with TC91 ) Broadband technologies and services using optical networking systems have come into widespread use, not only at the backbone level but also at the access level. As data bandwidths continue to increase, the optical interconnect must be driven even further down, to the system level, which requires the development of suitable opto-electronic packaging and interconnect solutions to accommodate the system environment.
Board mounted optical transceiver modules will increase in both channel count and data rate. In 201 1 , mid-board transceiver modules with 4 duplex or 1 2 single channels operating at 1 0 Gbps per channel were commercially available, with array subcomponents such as 4 and 1 2 channel VCSEL arrays and PIN photodiode arrays operating at up to 25 Gbps and single channel components operating at 40 Gbps available from certain vendors to enable 4 duplex channel 40 Gbps midboard transceivers and beyond. According to the board capacity trends shown, current 1 0 Gbps array technologies would typically require 30 optical channels per board, while the introduction of 40 Gbps array technologies in the near future would push this requirement to 1 00 optical channels per board.