This video shows the teardown of two Russian sensors. The first sensor is not a part of an Iskander missile but of a X-101 missile.
00:00 - Intro
00:25 - Optical sensor from X-101 missile
02:30 - 3-axis Fiber Optic Gyroscope (probably from Tornado MLRS)
Links
A picture of the first sensor with the optics:
https://photo.unian.info/photo/1173510-optiko-elektronnaya-sistema-korrekcii-starogo-obrazca-rakety-h-101
Several viewers have found the technical documentation of the Fiber Optic Gyro:
http://www.optolink.ru/documents/trs-500_RU.pdf
Other information concerning the FOG:
https://en.defence-ua.com/industries/the_life_of_american_astronaut_depends_on_the_intel_chip_from_aliexpress_used_in_russian_rocket_for_tornado_s_mlrs-6320.html
Technical documentation in russian:
https://ela.kpi.ua/bitstream/123456789/30573/1/Stranskyi_magistr.pdf