I recently bought a laser advertised as 'continous wave' operation but when I checked with a photodetector & oscilloscope I can measure that it is really a pseudo continuous wave with nanosecond pulse emissions.
Where do you buy true continuous wave lasers? And where will be the cheapest place to buy them?
There are many probable causes.
First answer a few questions for me and I'll take a look at your test setup and try to help you
1. What is the exact model number of the O-scope? ( I need this to verify both its bandwidth and sample rate)
2. Same goes for any test scope probe. Also tell me how the scope is setup as far as the selected Mega samples or Giga samples per second. This can also vary depending on how many channels are in use.
3. Model of the photodetector so I can make sure it's capable of this bandwidth.
These will help me get to the bottom of this and eliminate any aliasing of the signal that may be showing up on the scope.
4. Model of the laser head and driver (system), so I can take a llok at it's specs.
I know your interested in a very cheap (as far as cost goes) laser system, but with that you can't expect miracles of performance either.
My guess without knowing any of the details of your test setup is that what you're seeing is high frequency noise and that it probably is a continuous wave laser like they advertised, but does have high frequency noise as well.
