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![Explosion of functions and technology development in handheld devices [1].](profile/Marika-Immonen/publication/224197442/figure/fig1/AS:651873199616009@1532430090304/Explosion-of-functions-and-technology-development-in-handheld-devices-1.png)
Source publication
In this paper, we present active optical flex module aimed for mobile device applications. The module utilizes flexible optical waveguides on electrical printed circuit board for data links between high-speed interface devices, such as application processor-to-camera or display module. In this study, flexible and rigid-flex optical electrical circu...
Contexts in source publication
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... loss measurement setup is shown in (Fig. 11.a) Waveguides with mirror I/Os were measured with the modif ied setup shown in (Fig 11.b). The measurements were carried out using an ...
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... loss measurement setup is shown in (Fig. 11.a) Waveguides with mirror I/Os were measured with the modif ied setup shown in (Fig 11.b). The measurements were carried out using an 850nm ...
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... layer sustained undamaged during the pressing conditions (total time 185min, T =195 C, P =2,4 MPa). Increase in IL was < 0.035dB/cm. The results of the excess loss in -looped waveguides are shown in (Fig. 13). The results by the supplier indicate that with current waveguide materials, the minimum bending radius is 2.0mm with 0.5dB excess loss penalty. Since the OE-FPCs are designed for dynamic interconnections inside a phone, the optical FPC should possess excellent flexural and sliding characteristics at the small radius of curvature. ...
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... specif ication for bending radius is below 1mm. We aim to obtain R down to 1mm by new core/clad design. Results of the folding endurance tests are given in Table 2. for the free-standing optical flex and OE- Simulation results indicated that under natural convection conditions, T of each device exceeds max. allowable operation temperatures (Fig. ...
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... via matrix alone did not provide enough thermal conductivity (Fig. 14.b). With copper plane in contact with the backside of the ICs, the minimum thermal requirements were met for the embedded optical engine unit (Fig 14.c) ...
Citations
... WGs were designed with square step index profile in multiple core sizes (WxH) of 25x50µm 2 , 50x50µm 2 , 70x50µm 2 . Optical layers were fabricated in our production site as reported in [8]. For practical optical interconnect the maximum channel insertion loss is less than 10-12 dB. ...
... This is higher than obtained previously by the cut-back 0.1-0.15 dB/cm [8]. ...
... OPTOELECRONIC BGA MODULE ASSEMBLED ON O-PCB. DOUBLE LENS ARRAY AND TURNING MIRROR CHIPS ARE LOCATED UNDER MODULE[8]. ...
Purpose
The purpose of this paper is to study fabrication of optical‐PCBs on panel scale boards in a conventional modern PCB process environment. It evaluates impacts on board design and manufacturing with the developed optical board verifiers outlining challenges and requirements for manufacturing low‐loss waveguide structures and optical building blocks. The study aims to expand the current knowledge in the field by adding results obtained by utilizing industrial production infrastructure and developed scalable manufacturing processes to fabricate optical‐PCBs and board assemblies in high‐volumes and low‐cost manner.
Design/methodology/approach
Impacts on board design and manufacturing were studied with the developed optical technology verifiers. One verifier is optical‐PCB with embedded waveguides, integrated i/o couplers and optical vias. Another verifier is large size PCB with optical layer. A system‐level optical board assembly with 12.5 Gb/s Tx/Rx devices on surface mounted ball grid array (BGA) modules is designed for optical link analysis. Fabricated optical structures on verifiers are evaluated of their physical characteristics utilizing optical, SEM, LSCM analysis methods. Performance testing is conducted using standard optical transmission measurement methods and equipment.
Findings
The paper provides empirical results about fabrication of multimode optical waveguides with conventional PCB process equipment. Results suggest that current coating and imaging equipments are capable of producing optical waveguide patterns with high resolution and size accuracy. However, fabricators would require larger process window and defect tolerance for processing optical materials to obtain low‐loss waveguides with sufficient yields.
Research limitations/implications
Because of the limited amount of design variants in production verifiers evaluated in this paper, some impacts like effect of base material, board construction, optical layer location and beam coupling solution were not evaluated. Likewise, impacts on long‐term stability and cost were not addressed. These factors however require further investigation to address technical feasibility of optical PCBs technology prior commercial high volume production.
Practical implications
The paper includes implications for the development of a fabrication methods and testing procedures for optical polymer waveguide layers on PCBs.
Originality/value
This paper fulfils need to provide results on design, fabrication and characterization of optical PCBs and backplanes from industrial fabricator's perspective. The paper provides input for end‐user and developers to evaluate technical performance, robustness, and maturity of building blocks and supply chain to support polymer waveguide based technology for intra‐system optical links.
An optoelectronic interconnection module for mobile devices is required to have not only optical interconnection for high-speed and noise-free signal transmission but also many electrical wirings for multiple power supplies and low-speed signal transmission. It leads to great challenges of cost increase, flexibility degradation and electromagnetic noise emission. We propose a novel optoelectronic interconnection module for mobile devices in this paper. A hybrid configuration of an optoelectronic flexible printed circuit (OE-FPC) and an electrical FPC enables to minimize the cost, and a multi-fin structure fabricated by splitting the interconnection area realizes 3D flexibility which is not feasible with a conventional FPC. Magnetic near-field intensities of the optoelectronic interconnection module for mobile devices are shown for the first time. An ultralow-power and ultralow electromagnetic interference (EMI) optical signal transmission performance is demonstrated. It proves that the module developed in this work is highly promising for mobile devices in which signal integrity and EMI are growing into serious problems.
