Yes, the article concerns hybrid chips for use in fibre-optic...

Yes, the article concerns hybrid chips for use in fibre-optic data transceivers (in this case specifically a germanium photodetector on a silicon photonics platform). The SiGe BiCMOS chips mentioned in the article, combine CMOS logic with bipolar transistors (and other P-N junction devices).

Bipolar transistors don't get much publicity these days, but they used to be the backbone of the electronics industry. They remain the best option in many analogue applications, and this is the technology that puts them together with CMOS logic. CMOS logic is built up from gates, which are in fact a special type of the other class of transistor - the field effect transistor, or FET.

It is the sort of technology that will be needed to make quantum computing a commercial reality.

The next step is to combine GaN into these sorts of chips. This will be very challenging due to various incompatibilities between GaN and Si, particularly the large mismatch in thermal expansion coefficients. If integrating them on the same chip proves too difficult, then they can always be co-packaged.