Let's say there is a no-name SFP transceiver without a label and without DDM support. Is there a device which is able to detect on what wavelength this SFP transmits? I have used JDSU light-meters previously and they ask user to select wavelength(for example 1310nm, 1550nm), but regardless of the selected wavelength, they will show optical Rx power.

  • I doubt you want a simple yes/no answer, but product or resource recommendations are explicitly off-topic here. – Ron Maupin Jun 16 '16 at 14:21
  • I'm not looking for product recommendation. I would simply like to understand if this is possible or not. – Martin Jun 30 '16 at 9:39
  • You must have the transceiver installed in order for it to generate a signal, and you need to have access to the equipment in which it is installed to even try to test the light. Unfortunately, questions about a network over which you have no control are explicitly off-topic here. This question may be a better fit for Electrical Engineering Stack Exchange. – Ron Maupin Jun 30 '16 at 14:11
  • Did any answer help you? If so, you should accept the answer so that the question doesn't keep popping up forever, looking for an answer. Alternatively, you can provide your own answer and accept it. – Ron Maupin Aug 7 '17 at 13:59

Relying on SFP MSA is not a good options, as these specs are often faked to allow a specific switch to work with an incompatible device (I've see lots of bidirectionnal SFP which are identified as standard Single Mode SFP just because the switch was not bidir-compatible)

plugging another known SFP in front of the unknown device can give random results, and will not really help.

Using an OTDR will give you the answer, But it's quite expensive if you don't have one.

You can also use a Portable Optical Power Meter where the frequency is settable. it cost approx USD50 and it will give your the answer (and will also be really useful for debugging aso.)


Anything that conforms to the SFP MSA ("specs") has an I2C interface to a PROM with those values stored within it. I have yet to see an SFP (or SFP+) that did not have that interface.

  • Yes, but in rare occasions data stored in PROM can be inaccurate. In addition, this requires access to device where optical transceiver is inserted. I would simply like to know if there is an apparatus which is able to detect optical wavelength by measuring it. I have experience with JDSU light-meters and they ask user to select wavelength(for example 1310nm, 1490nm, 1550nm), but regardless of the selected wavelength, they will show optical Rx power, i.e it's not possible to say the Rx wavelength of the transceiver. – Martin Jun 30 '16 at 9:45

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