Loading... Please wait...


                                        Skyhunt Scientific Video List:

Sagnac interferometer (iFOG) Videos

A collection of videos on the construction of various fiber optic Sagnac interferometers.

1. Sagnac interferometer fiber optic Gyroscope (FOG) construction and testing.

Demonstration of a simple, low cost Sagnac interferometer, also known as a Fiber Optic Gyroscope ( FOG ). More info here.


2. Sagnac interferometer / fiber optic gyroscope (FOG) with

improved resolution

As a follow up to our first video, the Sagnac interferometer described herein can detect rotation as low as 1 revolution every 7 hours. Uses simple construction methods to keep the cost low.


3. Detecting earth's diurnal rotation using a large area

Sagnac interferometer.

This video describes the construction and testing of a Sagnac interferometer / Fiber Optic Gyroscope (FOG) sensitive enough to detect earth's rotation through space by detecting the speed of light difference in the clockwise and counter-clockwise directions from the perspective of the rotating observer. An article accompanying this video is available here.

4. iFOG Sagnac fiber optic interferometer with wireless data collection

In the fourth installment of our Sagnac series, we show the implementation of a wireless Bluetooth data logging system to collect the interferometer output data at various rotation rates and import it into an Excel spreadsheet.
Articles on the Sagnac Effect:

10) Doug Marett (2015) Single Mode Fiber Optic Sagnac Interferometer with Wireless Data Collection - Vixra e-print archive 1506.0002

11)  Doug Marett (2010)  How to Build a Sagnac Interferometer / Fiber Optic Gyroscope (FOG)

12) Doug Marett (2011) Detecting Earth's rotation Through Space Using a Large Area Sagnac Interferometer - article here

13)  Doug Marett (2012, 2015) The Sagnac Effect: Does it Contradict Relativity? General Science Journal  5993.

Fiber Optic Michelson interferometer videos

Building a fiber optic Michelson interferometer is tricky - here's how we did it.

5. A Fiber Optic Michelson Interferometer - first attempt.

This video describes the construction of an all fiber optic Michelson interferometer using Faraday rotator mirrors to overcome the birefringence issues encountered with single mode fiber. Part 1 of 2.  An article further describing this work is available here. (Doug Marett - Construction of an All-Fiber-Optic Michelson Interferometer )


6. Fiber Optic Michelson Interferometer Part 2: The Kennedy Thorndike Experiment.

In this second video we improve the fiber optic Michelson interferometer by making it more compact and adding a Bluetooth data logging system, as well as mounting it on a rotating platform. This allows us to attempt a Kennedy Thorndike type experiment, as well as a Shamir and Fox type experiment. The predicted outcome based on Lorentz ether theory is discussed by way of our on line simulators. An article accompanying this video is available here.


All prices are in US dollars


  • Electronics  3D printer electronic parts such as power supplies, heated beds, RAMPS boards / Arduino boards, NEMA 17 stepper motors, etc.
  • Magnets and ferrofluid  Ferrofluid demonstator kits, bulk ferrofluid and magnets. 
  • Motor kits  Permanent magnet motor kit
  • 3D printer kits TubularBot 3D printer kit and accessories
  • Meters and Measuring  Electromagnetic meters and other measuring equipment
  • Hardware  3D printer hardare, such as bearings, timing pulleys and belts, metric nuts and bolts, etc.
  • Fiber optics  Fiber optic gyroscope kits ( Sagnac interferometer ), fiber optic cables and couplers, adapters and other parts
  • Optics  Lens, mirrors, beamsplitters, laser position sensors ( quadrant detector ), optical mounts and optical tables
  • Plastic bottles  assorted sizes, including Nalgene leakproof storage bottles, and small dropper bottles