editor's blog
Subscribe Now

An Optical MEMS Reference Process

A while back Micralyne announced a MEMS reference process. There are a few of these running around: attempts to achieve – or at least grasp at – a standard process that can address a wide range of MEMS devices.

Most of Micralyne’s processes are confidential, per their customer relationships, in typical MEMS style. What they did here was to take a “neutral” improved version of what they do well and open it up. They’re not sure that customers will simply line up and use that process in high-volume production outright, but at the very least it’s a conversation starter and a way for them to show their capabilities without divulging secrets.

Micralyne’s strength is primarily optical MEMS: mirrors and comb drives and such. Those feature large in their process, but, in order to be a bit more general, they added some inertial devices, like a 2-axis (but not a 3-axis) accelerometer and a gyro, as well as some biomedical devices.

It’s a two-wafer process (plus handles); cavities are etched into the base wafer and the top wafer; the top wafer is inverted and fusion-bonded to the bottom wafer, after which the top-wafer handle is removed. From the top, release is performed and then metal is laid down. This metal step pertains in particularly to giving mirrors a nice reflective surface.

As a complete aside, in the discussion of their optical capabilities, there was repeated mention of “hitless” functionality with respect to the mirrors. I actually had a hard time finding out what this meant, and a conversation with Micralyne helped clarify. For any of you who are, like me, not steeped in optical, this is a way of changing optical routing in an optical switch without interfering with other channels.

It’s actually a pretty simple concept. Below I show a scenario with various fibers being routed to various other fibers via the gold mirrors. In particular, fiber 3 routes to fiber 1 (moving bottom to top). Let’s say we want to reroute that so that fiber 3 now routes to fiber 6. If we just move the mirror across, then the light stream from fiber three will interfere with all of the other receiving channels as it scans across (which I’ve tried to illustrate on the right, with the stars indicating interference as the beam moves; at the particular moment shown, it’s made it as far as target fiber 4 on its way to 6).

Hitless_switching_1.png

So the hitless idea is that you simple tilt the mirror in the orthogonal direction first so that it’s no longer targeting the receiving fibers. You can then sweep it across to the new target; the light is now moving under the other beams and doesn’t interfere. Once over in the new position, you then bring the beam back up to its normal working position and the connection is made (with no disturbance to the others).

Hitless_switching_2.png

You can find more info in their release and whitepapers.

Leave a Reply

featured blogs
Jul 9, 2020
I just read '€œEmpty World'€ by John Christopher, and I'€™m sure you will be as amazed as I to discover that this book has a hint of a sniff of the post-apocalyptic about it....
Jul 9, 2020
It happens all the time. We'€™re online with a designer and we'€™re looking at a connector in our picture search. He says '€œI need a connector that looks just like this one, but '€¦'€ and then he goes on to explain something he needs that'€™s unique to his desig...
Jul 3, 2020
[From the last episode: We looked at CNNs for vision as well as other neural networks for other applications.] We'€™re going to take a quick detour into math today. For those of you that have done advanced math, this may be a review, or it might even seem to be talking down...

Featured Video

Product Update: Advances in DesignWare Die-to-Die PHY IP

Sponsored by Synopsys

Hear the latest about Synopsys' DesignWare Die-to-Die PHY IP for SerDes-based 112G USR/XSR and parallel-based HBI interfaces. The IP, available in advanced FinFET processes, addresses the power, bandwidth, and latency requirements of high-performance computing SoCs targeting hyperscale data center, AI, and networking applications.

Click here for more information about DesignWare Die-to-Die PHY IP Solutions

Featured Chalk Talk

The Future of Automotive Interconnects

Sponsored by Mouser Electronics and Molex

The modern automobile is practically a data center on wheels, with countless processors, controllers, sensors, and intelligent systems that need to communicate reliably. Choosing the right interconnect solutions is front and center in the design of these complex systems. In this episode of Chalk Talk, Amelia Dalton chats with Rudy Waluch of Molex about interconnect solutions for today’s automotive designs.

Click here for more information about about Molex Transportation Solutions