Isn't this sensor a lot or exactly like how the Powerglove works?

It's how Jaron Lanier's DataGlove worked. The Power Glove used cheaper flex sensors instead of fiber optics.

https://en.wikipedia.org/wiki/Power_Glove

There are a lot of similarities in the approach to the linked paper (which is a very cool concept) and I saw a lot of similar concepts in my lit review. At a high level, my sensor targets bend localization with simple fabrication techniques while the linked paper is doing more general camera-based gesture recognition. I have a more thorough comparison to existing work in my actual dissertation.

Our lab has done a good bit of work around elastomers similar to the linked paper, such as multitouch pressure sensing (https://ieeexplore.ieee.org/abstract/document/9674750). The authors of your linked paper can actually achieve what they've done with a single light source by using one of these! The zones are key (https://www.st.com/en/imaging-and-photonics-solutions/time-o...)