An Illuminating Chat with Lumerical's CTO

During the recent photonics summit, I sat down with James Pond, the CTO of Lumerical along with Rich Goldman who is doing their marketing. At CDNLive in Munich earlier in the year I got a brief demo of the Lumerical software. Their main products provide simulation of optical devices used in photonics. But in the context of silicon photonics the important thing is that they provide co-simulation of electronic and photonics circuits within Cadence's Virtuoso environment. This enables a true joint development flow, where some of the polygons represent optical devices, and some represent electronic devices.

History of Lumerical

James was one of the founders of Lumerical. All the founders came from a company called Galian Photonics that was founded in the late 1990s to commercialize photonics crystal technology. They were based in Vancouver, Canada. Luxtera started at the same time. They found that they could not buy the simulation tools that they needed and so they build them in-house. Gallian survived until 2002/3 when the telecom bubble finally collapsed and they closed the doors. But a group of them said to themselves, "if we couldn't find these tools and had to build them then maybe there are other people out there". They had built a grating coupler (still used by Luxtera) and they could simulate it in about 10 hours on what was one of the top 500 supercomputers at the time. If you are thinking of the fancy pictures you have seen of top-of-the-line supercomputers, then think again. This was a stack of boxes in the hallway. That grating coupler is still one of the two standard I/O ports in silicon photonics.

So when Galian wrapped up, a group of four of them decided to start a software company, Lumerical. Three of the four are still there (the 4th became a professor at Queen's University in Canada). They created one of the most powerful solvers, written from the start to be parallelized and run on supercomputers. Now, with the increase in performance since 2003, it can run on a single server in ten minutes.

In the early days, just after the telecom bubble burst, integrated photonics was not a key area since nobody was doing anything. Lumerical started expanding and had software that could be applied in lots of areas, such as plasmonics and heat-assisted magnetic recording (HAMR). In the first years, they found niches outside of integrated photonics.

But in 2010, although you could see it a couple of years before, there was a sudden increased interest in silicon photonics and integrated photonics. The manufacturing problems had been solved. So they adapted the technology with features that supported integrated photonics. They still have a diverse set of customers doing various things, but the fastest growing area is integrated photonics.

Currently, they are over 50 people. They are still fairly small, but they are riding the silicon-photonics wave and growing fast.

Products

James said that the best way to think about what they do is TCAD in the semiconductor world, providing FDTD (finite-difference time-domain) simulation starting from a very low level. Their focus is photonics devices, of course, not transistors, so even though they have a charge-transport solver and a heat-transport solver, their focus is photonics. 

In purely optical devices you are often simulating just the optical S-parameters. For example, for a grating coupler, you want to know the transmission and reflection as a function of wavelength. But for active devices, such as a phase shifter in a wave guide, you need to combine optical and electrical simulation. You want to know how much voltage you need to apply to produce a π shift in the wave guide. The point of all this physical simulation is to optimize and improve designs. But another important aspect is parameter extraction, since then you can make behavioral models for larger scale photonics simulations. That way you can simulate a whole photonics system. But any real system requires electronic drivers and receivers, so this needs to be co-simulated with Spectre.

As an example, James described one customer who is using microwave into electronics, and then using that to drive a modulator that transfers the signal into light. At the other end there is a photodetector, a transimpedance amplifier (TIA), then more electronics. So even something as "simple" as an RF-photonic link like this requires both Lumerical and Cadence working together. Virtuoso drives the whole thing from one end to the other.

Users know that Lumerical is running, it's not a secret, but they know it is being managed for them in an integrated environment. They can monitor electrical, optical, power, phase, all from inside the ADE cockpit.

James is proud that Lumerical is considered the leading simulator company. Indeed, in Vladimir's opening keynote at the photonics summit, he said about some work they were doing that "the key thing is how it compares to Lumerical." They are the gold standard.

For silicon photonics, hundreds of components is big. During the keynote, one simulation had been:

one of the largest ones: 20 million transistors and 750 optical components. That counts as really big.

Learn More

You can learn lots about Lumerical on their website. The photonic circuit simulator product is called INTERCONNECT. You can get a free 30-day trial. You also need the Virtuoso Photonics Option to make photonics and electronics work together. Information about Cadence's photonics solution is on the Photonics Page.

Sign up for Sunday Brunch, the weekly Breakfast Bytes email.