Photodetector Output & Refractive Index of FO Cladding/Coating

[benagastov]

After I finished preparing gas chamber for testing optical fiber as gas sensor, my supervisor asked me to measure the difference of refractive index from several optical fiber with different coatings. I knew there is Evanescent Field and Skin Depth effect, but what kind of mathematical formula that related with Photodetector's voltage output or Luxmeter's lux output?

I got my nanofiber experiment cancelled due to difficulty to attach that nanofiber into optical fiber's core. But I still have some time to use dipcoating method, and try again doing electrospinning next semester. Unfortunately, I still dont understand this basic concept how the photodetector works. I read about quantum efficiency, photoelectric effect, etc. But still have no clue.

 

[member38644]

The photodetector output is directly related to the refractive index of the optical fiber cladding/coating. This is because the refractive index determines the amount of light that is transmitted through the fiber and reaches the photodetector. The higher the refractive index, the more light is transmitted and the higher the photodetector's voltage output or luxmeter's lux output will be.

In order to understand the mathematical formula that relates the photodetector's output to the refractive index, it is important to first understand the concept of quantum efficiency. This is a measure of how efficiently the photodetector converts incident light into an electrical signal. The higher the quantum efficiency, the more sensitive the photodetector will be to changes in the refractive index of the fiber.

The photoelectric effect is also important to understand in this context. This is the process by which photons (particles of light) are converted into electrons, which can then be measured by the photodetector. The amount of electrons produced is directly proportional to the intensity of the incident light, which is in turn dependent on the refractive index of the fiber.

In summary, the mathematical formula that relates the photodetector's output to the refractive index of the fiber is based on the principles of quantum efficiency and the photoelectric effect. By understanding these concepts, you will be able to accurately measure and compare the refractive index of different fibers with different coatings using your photodetector.