Integration of optical interconnections on circuit board (original) (raw)
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Integration of Optical Interconnects on Circuit Board
Hybrid integration of polymer-based micro-optical technologies allows implementing high-bit-rate optoelectronic interconnects. The target is communication between surface-mounted integrated circuit packages on printed circuit board through embedded optical waveguides. Different kinds of optical elements for coupling between transmitters/receivers and waveguides are studied, including microlens arrays, microlenses integrated on VCSELs, surface-mountable beam deflecting elements, optical pillar structures, and waveguide structures patterned by laser ablation. Integration experiments by the use of ceramic packaging substrate as well as results of the coupling efficiency and alignment tolerance characterizations are presented.
Integration of optical interconnections on circuit board (invited paper)
2007
Hybrid integration of polymer-based micro-optical technologies allows implementing high-bit-rate optoelectronic interconnects. The target is communication between surface-mounted integrated circuit packages on printed circuit board through embedded optical waveguides. Different kinds of optical elements for coupling between transmitters/receivers and waveguides are studied, including microlens arrays, microlenses integrated on VCSELs, surface-mountable beam deflecting elements, optical pillar structures, and waveguide structures patterned by laser ablation. Integration experiments by the use of ceramic packaging substrate as well as results of the coupling efficiency and alignment tolerance characterizations are presented.
Optoelectronic Interconnects V, 1998
(UCSD), sponsored by DARPAIETO, to develop affordable optoelectronic packaging and interconnect technologies for board and backplane applications. Specifically, progress [1 ,2] is reported on (a) development of a plastic VCSEL array packaging technology using batch and planar fabrication, (b) demonstration of high-density optical interconnects for board and backplane applications using polymer waveguides to a length of 50 cm at an 110 density of 250 channels per inch, (c) development of low-loss optical polymer waveguides with loss less than 0.1 dB/cm at 850 nm, and (d) development of passively alignment processes for efficient coupling between a VCSEL array and polymer waveguides. Significant progress has also been made under the POINT program at Columbia University, in applying CAD tools to simulate multimode-guided wave systems and, at UCSD, to assist mechanical and thermal design in optoelectronic packaging. Because of space limitations, these results will be described elsewhere in future publication.
Embedded optical interconnect on printed wiring board
2004
Integration of high-speed parallel optical interconnects into printed wiring boards (PWB) is studied. The aim is a hybrid optical-electrical board including both electrical wiring and embedded polymer waveguides. Robust optical coupling between the waveguide and the emitter/detector should be achieved by the use of automated pick-and-place assembly. Different coupling schemes were analyzed by combining non-sequential ray tracing with Monte-Carlo tolerance simulation of misalignments. The simulations demonstrate that, with optimized optomechanical structures and with very low loss waveguides, it is possible to achieve acceptable total path loss and yield with the accuracy of automated assembly. A technical demonstrator was designed and realized to allow testing of embedded interconnects based on three different kind of optical coupling schemes: butt-coupling, and couplings based on micro-lens arrays and on microball lenses. They were implemented with PIN and flip-chip-VCSEL arrays as well as 10-Gb/s/channel electronics onto LTCC-based (low-temperature co-fired ceramic) transmitter and receiver modules, which were surface mounted on high-speed PWBs. The polymer waveguides were on separate FR-4 boards to allow testing and characterization of alignment tolerances with different waveguides. With micro-lens array transmitter, the measured tolerances (±10 µm) were dominated by the thickness of the waveguides.
Applied Optics, 2007
Optical interconnects can provide chip-to-chip data communication with much needed bandwidth as processor speed and density keep growing. Optical waveguides and couplers are essential components for implementing optical interconnections. Techniques for directly dispensing polymer waveguides in laserablated trenches on printed circuit boards and for fabricating optical couplers are presented for quick prototype of optical interconnects. High-quality UV curable polymer waveguides were routinely fabricated. High-efficiency couplers, blazed grating couplers on sloped waveguides, sloped facet metal film couplers, and reflective-undercut facet couplers can be fabricated by using excimer laser ablation.
2008
An investigation study concerning optical fiber alignment and micro-mirror performance in MOEMS devices is being reviewed in this paper. The central attention of the study is the analysis of optical fibers positioning, alignment, bonding, optical improvements, coupling to micro-lenses for beam collimation and waveguides. Also, we highlight features concerning coupling of optical fibers to micro-mirrors while searching for the proper alignment and characterization of the optical beam reflection, its tolerances, relative positioning, and attachment techniques. This Part II presents assembly procedures and experiments considering the first Part I of this work.
Superficies Y Vacio, 2008
An investigation study concerning optical fiber alignment and micro-mirror performance in MOEMS devices is being reviewed in this paper. The central attention of the study is the analysis of optical fibers positioning, alignment, bonding, optical improvements, coupling to micro-lenses for beam collimation and waveguides. Also, we highlight features concerning coupling of optical fibers to micro-mirrors while searching for the proper alignment and characterization of the optical beam reflection, its tolerances, relative positioning, and attachment techniques. This Part II presents assembly procedures and experiments considering the first Part I of this work.
IEEE Transactions on Advanced Packaging, 2000
The first, to our knowledge, passive, precision, selfalignment technique for direct coupling of vertical cavity surface emitting laser (VCSEL) and photodiode (PD) arrays to an array of polymer buried channel waveguides on a rigid printed circuit board (PCB) is reported. It gives insertion losses as good as the best achieved previously, to within experimental measurement accuracy, but without the need for costly active alignment nor waveguide facet polishing and so is a major step towards a commercially realizable low cost connector. Such an optical connector with four duplex channels each operating at 10 Gb/s (80 Gb/s aggregate) was designed, constructed, and its alignment precision assessed. The alignment technique is applicable to polymer waveguide interconnections on both rigid and flexible multilayer printed circuit boards (PCBs). The dependence of optical coupling loss on misalignments in , and of the VCSEL and PD arrays allows the precision of alignment to be assessed and its reproducibility on multiple mating cycles of the connector is reported. The first recorded measurements of crosstalk between waveguides when the connector is misaligned are reported. Lateral misalignments of the connector to within its tolerance are shown to have no effect on the signal to crosstalk ratio (SCR), to within experimental measurement accuracy. The insertion loss repeatability is similar to that of single mode fiber mechanically transferable (MT) connectors.
Hybrid Integration of End-to-End Optical Interconnects on Printed Circuit Boards
IEEE Transactions on Components and Packaging Technologies, 2007
This paper discusses the integration of an end-to-end optical interconnect testbed on printed circuit boards using inexpensive off-the-shelf, bare die, optoelectronic components. We developed a process for efficient and simultaneous in-plane optical coupling between edge emitting laser and waveguides, and between photodetector and waveguide. We demonstrated an optically smooth buffer layer separating the printed circuit layer from the optical transport layer. The demonstrated radically new optical interconnect technology, which we refer to as interface optical coupling, is able to efficiently and simultaneously form optical interfaces between waveguides, lasers and photodetectors by photolithographic technique, thereby eliminating the need for micro-lenses and manual alignment. The measured laser to waveguide coupling efficiency is 45% and measured waveguide to photodetector coupling is 35%. The optical link is demonstrated to operate at 10 Gbps. Index Terms-Chip-to-chip, embedded devices, optical communication, optical integration, optical interconnect, polymer waveguide, printed circuit boards (PCBs), system-on-package (SOP). I. INTRODUCTION A S THE digital processor continues to scale down and the processing speed increases as predicted by Moore's law, the signal transport by electrical interconnection on printed circuit boards (PCBs) becomes a limiting factor for further improvement of a digital system due to its complexity in system layout, power consumption, electromagnetic interference, etc [1]. Optical interconnect is a promising solution in routing and distributing data at bit rate in multi-gigabits to above 10 Gpbs in distance less than 50 cm. In recent years, a number of chip-tochip optical interconnect technologies have been demonstrated, including thin film device optoelectronics [2], embedded active and passive component integration [3], [4], hybrid packaging of electronic and optical component [5], [6], optical board technique [7], [8], etc.