GAP1093 phototransistor for OPM4 fiber meter needed.

[Ordinaryman1971]

I'm looking for replacement for this photoelement on the fiber meter made by Noyes OPM4.
It's marked as GAP1093.

[Ordinaryman1971]

Here are pictures of meter and the sensor

[Kleinstein]

It is very likely not a photo transistor, but a photodiode.  Optical fibers often use some 1.55 µm and thus can not use si detectors anymore. With the longer wavelength materials phototransistors are not at all common - likely not available at all.

[Ordinaryman1971]

I've done some google-fu and nothing came up, you are most likely right.
So... if they are not silicon based... what would be the material used for the detector part.

[Kleinstein]

My best guess on the detector material is InGaAs, as this is good to some 1.8 µm wavelength and still available as a standard type. Even mouser has a few in stock.

Another possibility may be using a thermopile to get a wavelength independent response, though at a much lower sensitivity and thus only a thing for relatively high power.

[Haenk]

https://www.aflglobal.com/emea/-/media/Project/AFL-Global/Product-Specification-Sheet/Test-and-Inspection/Optical-Loss-Testing/opm0-00-2000.pdf

It has wavelengths and type of detector - which might help to find a replacement.