Strategies for glass based photonic system integration

There is a clear tendency to integrate more and more opto-electronic and micro-optical components like optical fibers, laser diodes, modulators, isolators, beam-splitting components and micro lenses in also increasingly dense and complex assemblies. The paper will discuss thin glass as a very promising base material for that kind of photonic packaging on interposer and board level including optical interconnection using fibers

"glassPack": A novel photonic packaging and integration technology using thin glass foils

"glassPack" will be introduced as a novel photonic packaging concept for a wide area of applications like high-speed electronic systems and sensors. The usage of thin glass foils with a thickness of some tens of microns as substrate and interconnection material will be discussed. Photonic packaging in such hybrid optoelectronic systems involves single packages, modules, and subsystems comprising at least one optoelectronic device, micro-optical element or optical interconnection. Thin glass is a commercially available and reliable material with high thermal resistance and excellent optical properties. Because glass is a well known material, many technologies like polishing, plating, etching and refractive index tuning are already known. In combination with newly developed integration technologies, a complete glass based package on wafer level can be realized. The main ideas of the "glassPack" concept are: selection of suitable glass foils as substrate material, realizat ion of microsystem compatible structuring technologies like cutting, drilling and etching, integration of optical waveguides by ion-exchange for single- and multi-mode applications, implementation of optical interconnects between fibres and integrated waveguides by laser fusion, integration of electrical wires and feed throughs, assembly of electronic and optoelectronic components, and bonding of the thin glass foils to 3D-stacks. Furthermore, the integration of micro fluidic channels into a "glassPack" will be supported. A sensor module containing optical waveguides, fluidic channels, electrical wires and components like a laser, two photodiodes and two flip-chips will be presented to demonstrate the suitability of glass as a material for integrated microsystems

Embedded planar glass waveguide optical interconnect for data centre applications

Electro-optical printed circuit boards (EOCB) based on planar multimode polymer channels are limited by dispersion in the step-index waveguide structures and increased optical absorption at the longer telecom wavelengths [1]. We present a promising technology for large panel EOCB based on holohedrally integrated glass foils. The planar multimode glass waveguides patterned into these glass foils have a graded-index structure, thereby giving rise to a larger bandwidthlength product compared to their polymer waveguide counterparts and lower absorbtion at the longer telecom wavelengths. This will allow glass waveguide based EOCBs to support the future bandwidth requirements inherent to large scale data centre and high performance computer subsystems while not incurring the same dispersion driven penalties on interconnect length or loss dependence on wavelength. To this end glass foil structuring technologies have been developed that are compatible with industrial PCB manufa cturing processes. Established processes as well as new approaches were analysed for their eligibility and have been applied to the EOCB process. In addition a connector system has been designed, which would allow optical pluggability to glass waveguide EOCBs

Glass carrier based packaging approach demonstrated on a parallel optoelectronic transceiver module for PCB assembling

Glass as a carrier material for electrical and optical interconnects has many benefits compared to conventional materials like silicon, ceramic or polymer based laminates because of its excellent dielectric and transparent properties that are becoming important for electrical high-frequency signal wiring as well as for optical wave guiding. Furthermore, the integration potential of glass is excellent because of the dimensional stability under thermal load and the coefficient of thermal expansion matching that of silicon ICs. A small pitch size of conductor traces, small scale through-vias and high alignment accuracy are the key requirements that will be achieved from glass carrier based packaging. Another outstanding benefit is the transparency of glass that allows the planar integration of optical waveguides inside the glass core material and the light transmission through the carrier between different optical layers. This paper presents a four channel bi-directional o ptoelectronic transceiver module that was designed and processed using the glass carrier based packaging approach called glassPack. The transceiver operates with 10 Gbps per channel and has an extremely low power consumption of 592 mW. The module is mounted on a printed circuit test board and the performance is characterized by bit error rate testing

Evaluation of graded index glass waveguides for board-level WDM optical chip-to-chip communications

A Proof-of-Concept for a multi-channel WDM board-level optical communications link is under development. This paper is focusing on theoretical and experimental evaluation of thin-glass based nearly single mode graded index optical waveguides with regard to low loss in the 1310nm regime. Results from waveguide characterization will be reported. Waveguide modes are determined theoretically from the measured refractive index profiles. Towards improvement of the robustness of the coupling efficiency against misalignments, investigations on the use of tapered waveguide structures will be presented too

Low-loss telecom wavelength board-level optical interconnects in thin glass panels by ion-exchange waveguide technology

An optical interconnection technology for 1310 and 1550 nm has been developed by using commercial available thin glass panels for waveguide fabrication. Process and mode-field distribution can be designed according optical requirements and simulated by combined FEM algorithms

SiN-assisted flip-chip adiabatic coupler between SiPh and Glass OPCBs

We demonstrate, for the first time to our knowledge, a SiN-assisted in-plane adiabatic coupler between SiPh and onboard glass waveguides. Our numerical study is founded on an actual graded index glass waveguide developed by Fraunhofer-IZM. The Silicon taper profile and the optimal length are extracted employing the supermode theory and the adiabatic theorem. Fabrication and assembly issues are investigated, resulting to an optimized coupler design that exhibits a theoretical Si-to-glass loss below 0.1dB over the entire C-band. The proposed solution can be realized utilizing standard passive flip-chip assembly equipment and is, therefore, cost-effective, easy to be fabricated, and well-suited for compact packaging