Optical Printed Circuit Board Technology
The next generation of internet switches and high-end computers are expected to process data at Tbit/s aggregate speeds. As a result, the interconnections between the processing units will have to handle data speeds of 10 to 40 gigabits per second. At such data rates, traditional electrical connecting technology will suffer from substantial transmission losses and serious integrity issues.
Optical PCB interconnects are thought to be the best option. Using optical waveguides in printed circuit boards has a number of advantages over using traditional PCBs. They are as follows: increased data transmission rate, smaller electrical connection physical size, lower material cost, and lower power consumption
Telecommunications, photonic connectivity, Opto-Micromachine, and other fields can benefit from optical PCBs.
Waveguide fabrication materials and processing processes have been the focus of research for several years. Now many of technological limitations in optical PCB processing technologies has been resolved to enable manufacturing of optical PCB such as :
- Photo imaginable waveguide material has been developed to achieve functional and processing requirements.
- Imaging processing technique has improved that ensures the waveguide layer’s dimensional integrity.Optical PCB reliability has been improved.
- Optical PCB relibality has been improved.
Optical Interconnect Options for PCBs
Glass fibres embedded in the interior layers of a multilayer PCB are the two greatest solutions for optical interconnects in PCBs. Polymer waveguides can also be deposited on the internal layers or surface layers. Glass fibres might also be used on the surface layer, but polymers allow for more precise geometric control.
Because the geometry and coupling optics must be accurately determined on the surface layer when interacting with optical components, this becomes critical. Because optical interconnects do not have the same signal integrity issues as interconnects, the design process will not alter significantly regardless of which approach is chosen.
Because glass optical interconnects can be incorporated in the core or prepreg layers, they will most likely be the easiest to integrate into typical multilayer PCB production processes. Between FR4 laminates, the proper material can operate as a cladding layer for glass waveguides. Glass and polymers might be employed in the same layer; normal optical fibre glasses could be used in the inner layer, while polymers would be easier to deposit on the outer layer.
Glass or polymer waveguides in the interior layers of a PCB require transmission back to the surface layer and coupling optics for EPICs/PICs, or the use of a fast-responding photodetector (normally a PIN photodiode). An optical connection requires some type of coupling optics in the form of 45-degree mirrors, especially in optical BGAs for EPICS and PICs. This necessitates ultra-precise micromanufacturing. Otherwise, in an optical link, the laser diode and receiver must be integrated in the substrate.
Drivers and Motivation: Power and Signal Integrity
Is the Copper PCB Trace Dead?
The demise of copper has been just a couple of years in the future for the last 20+ years but this time it appears to be different —not only is signal integrity becoming a significant gating factor so is power. Optical solutions offer significant advantages over copper on both counts
Optical PCB – TRENDS & ROADMAP
Optical PCB Overview
Polymer Waveguide Fabrication Processes and Integration to OE PCB
Examples Of Optical PCB Stack-up
PCB Design and Optics
Optical systems have mostly been commercialised through fibreoptic cables for internet technologies to date.
However, optical layers on a PCB have been utilised to send data around the board between components in a variety of technologies. This is accomplished with specific 90° grooves that can produce optical vias, allowing light to pass through to the component layer.
While inter-optical connections on a single PCB are possible, they will only boost the board’s local bandwidth. What we truly need is the ability to connect individual PCBs to an optical backplane, which would allow massive computer systems to send data across hundreds of boards. Without the use of multiple fiberoptic cables, such a solution would reduce the complexity of linking boards. Direct optical communication between ICs is also possible.
Summary and Key Takeaways
- System and component power has become first order issue and drive new solutions development.
- Hybrid PCB with copper and optical offer a viable 112/ 224Gbps solution -no re-timers, no cables, exploits best of both worlds.
- Capability to build optical PCBs using standard high vol. scalable processes. Multimode solution is mature, lower cost, robust vs. Single Mode.
- Strong eco-system partnering with material , connector, EMS/ test developer to align customer roadmaps, readiness and multi-sourcing.
- New Products in Pipeline : Single mode polymer waveguide products.
Cerra Systems is one of the leading PCB manufacturing solutions providers with PCB manufacturing plants located in North America, Asia with certifications for MIL, AS, TS, ISO, & NADCAP. Our products are Rigid, Flex, Rigid-flex, HDI, RF, and hybrid PCBs addressing up to 64 layers and 2 mil technology. Cerra Systems Major PCB Market is Aerospace, defense, Medical, computing, cellular & Industrial.
We manufacture and supply a wide range of Printed Circuit Boards in India from very small, double-sided PCB to high layer count, high-density multi-layer boards to large tabletop size backplanes. We have dedicated and quick-turnaround operations capable of delivering PCB prototypes with a lead time as short as 24 hours. We also offer quick-turn prototyping with a lead time as short as 5 days, depending on the technology and layer counts.
For more details, visit us- http://cerrasystems.com/