More info and article ref'd not that original
There are better technical articles that predate the one referenced here.. and they don't have a paywall..
One at (dates to 2014):
google ref - they may be 'filtering'.
RE: Measuring rotation - Ring Laser Gyroscope
There is also something known as Fiber Optic Gyros (also a MIT project) - also known as FOGs. The Ring Laser Gyros tend to be a bit fragile(more than they claim in shock/impulse), have experience with the Honeywell HG1700 IMU. Not the quietest RLG. To avoid optical resonance lockin on the injected laser signal, the laser assembly is rapidly rotated back and forth at about 450Hz.
FOGs tend to be a bit simpler, smaller, quieter. MEMs gyros are also another interesting gyro source (least accurate of RLG and FOGs). Many commercial drones (and OTC drones) are aided by simple MEMs gyros.