Single-mode glass waveguide platform for DWDM chip-to-chip interconnects

Due to high bandwidth potential, optical single-mode signal transmission is superior to electrical as well as optical multimode signal transmission. For years, optical single-mode fiber cables have been used in telecommunication networks. However, there is a lack of photonic system integration based on optical single-mode interconnects in printed circuit boards and modules for signal transmission between electro-optical components and optical fibers. Therefore, a thin glass-based photonic integration concept for single-mode signal transmission was developed. Optical waveguides and optical free space interconnects are integrated in a single or a stack of thin glass sheets for module and printed circuit board packaging. For light routing inside a thin glass sheet, a singlemode waveguide technology on wafer level (150 mm) was developed promising for scaling up on panel size (45 × 60 cm²). The waveguides show single-mode behavior, low propagation (0.05 dB/cm) and fiber coupling (- 0.3 dB) losses at wavelength of 1550 nm. Different waveguide structures such as 180°-bends, S-bends, splitters and crosses have been integrated in thin glass and characterized in detail. Coupling mechanism and misalignment loss has also been studied. Technologies for fiber laser joining on glass as well as laser structuring of an optical mirror are introduced and first results are presented. Generic module and board-based photonic packaging solutions can be put into practice by applying all introduced technologies and will be demonstrated for a chip-to-fiber module package platform.