Intensive research on optical interconnections has attracted considerable attention for high-end router and server
applications. A polymer film waveguide is expected to be applied to an optical circuit board in an optical
interconnection. The film waveguide requires a conventional connector if it is to be employed as a practical optical
circuit board. This paper describes the MT connector used with polymer film waveguide (PMT connector), which is
compatible with the MT connector used with optical fiber. This connector can be attached to a film waveguide by
passive alignment, and is used to connect waveguides. When the connector was equipped with an epoxy resin film
waveguide, the insertion and connection losses were less than 1.4 and 0.5 dB, respectively. These losses are sufficiently
small to meet the basic requirement for optical circuit boards, so we were able to fabricate a flexible optical circuit board
with PMT connectors. This paper also describes the application of a film waveguide with PMT connectors to an optical
front plane system.
Parallel optical interconnection modules has been used for inter- and intra- hardware systems to overcome the bottleneck of electrical interconnection. The next-generation high-throughput telecommunication systems over several tera-bit-per second and high-speed computer systems over several GHz require chip-level optical interconnection as well as MCM-level optical interconnection. This paper describes chip-level optoelectronic packaging technologies to construct future high-performance telecommunication and computer hardware systems. The key technologies include optoelectronic chip on film(OE-COF) packaging technology, and fiber-less optical I/O-BGA packaging technology using microlenses for optical input or output terminals. The OE-COF is composed of flip-chip bonded optical devices and LSIs on the optical waveguide film with impedance-matched electrical lines for flexible OE packaging. The BGA package can allow wide-misalignment of ±50μm, which is compatible with the performance of current electronic assembly machines, and is useful for high-density and low-cost packaging on boards.
Polyimides are widely used in electronics as heat-resistant organic materials and are now being studied for possible use in optical components. The fluorinated polyimides developed by NTT have high transparency at telecommunication wavelengths, a controllable index of refraction, and high thermal stability, making them suitable for use in optical communication systems. Here, optical components developed using fluorinated polyimides are reviewed, and the relationships between the material characteristics and the device parameters are discussed.
New packaging techniques for opto-electronic multichip modules (OE-MCMs), including OE substrates and optical coupling between a waveguide and a flip-chip bonded photodevice or fiber, are presented for high-speed and wide-band communication systems. The OE substrates, which offer high-density, high-speed optical and electrical interconnection, are made from low loss (0.4 dB/cm) optical polyimide waveguides fabricated on copper-polyimide electrical multilayer substrates. A total internal reflection mirror fabricated at the edge of the optical waveguide reflects the light propagating from the waveguide to a flip-chip bonded photodiode with a loss of less than 1.5 dB. The waveguides are coupled to fibers for inter-module interconnection using the self-aligning fiber guiding method.