Year of the Chip
My 2019 has been hectic! My calendar has never been so packed and I was so fortunate to be invited to do amazing things, meet fantastic people, and most importantly, stay doing what I love the most - research.
This year I ended by EPSRC Doctoral Prize Fellowship in May and took a mini postdoc position for a few months until my RAEng fellowship started in October. What does this mean? No time for publications! And that’s perfectly fine, because guess what? My fellowship application took nearly 2-3months to write and complete, and I also submitted a bunch of failed and successful grant applications too! However, in the background, since 2018, I’ve been trying to get myself towards silicon photonics. My career has revolved around bulk optics and optical fiber work (manipulating fibers, tapering them, melting them!) - getting myself to a clean room is almost impossible (you need training money and also access to a clean room) but luckily there are plenty of multi-process-wafer services that allow cheap R&D work. They’re like fixed process schemes so your design is limited but its hugely cost effective. I designed my second masks ever (I was trained to work in the BAE Systems clean room in Filton many years ago) and they got made by Cornerstone in Southampton.
After all the delays i.e. trying to find a wage and funding, me and Zhimeng set up the chip-testing rig - once again, totally new and ridiculously fiddly. A few days before flying out to SPIE I got light through the chips! This is done by positioning a stripped optical fiber and angling it around 7 degrees (awkward upwards slant!) - you then need to carefully position the fiber end over the Bragg grating structure at the end a strip waveguide. This is made more difficult because you need another one on the other end of the waveguide to see if any light has gone through. It’s a two body problem with over 6 degrees of freedom to get wrong!
One of the strip waveguides is positioned next to a ring resonator. By tuning the wavelength (detuning the frequency) of the input light we find whispering gallery mode resonances. This is a huge step for me as I previously hand-fabricated EVERYTHING (the super thin waveguide, glass spheres that have whispering gallery mode resonances) but it comes at a cost; the structures are etched, not melted, so they have rough surfaces and are very lossy. You win some you lose some!
I start 2020 as a bonafide optical chip researcher, and soon to be, MEMS (micro-electro-mechanical systems) researcher. I have so much to learn in these fields, but I bring my own expertise in optics, optomechanics, and systems engineering. I dreamt of doing chip-work a few years ago, and I’m kinda proud of myself that I got there, somehow.
