Range Finder question - Optical Filter for an APD

[bebetxx]

Hi!

I am working in a range finder project. I have encountered a problem with an Avalanche Photodiode. I am trying to use a pulsed laser on 980 nm(infrared) but I receive a lot of noise from the APD.

I want to ask you if in the APD must be totally dark and no other light must enter in the APD box?

Do I need to use a infrared optic filter? What kind of optical filter do I need to use? I use a lens with 10 cm diameter .

Thank you, I am not physicist, I am a programmer and an electronist

[swansont]

It would almost certainly help to filter the light. You want a 980 nm bandpass filter.

[Enthalpy]

Why an avalanche photodiode? They use to serve for very faint light. Besides being less convenient to use, they would be flooded with light in a normal ambient.

 

In case your design relies on signal processing to extract the echo from ambient light, rather than from heavy filtering on wavelength and direction, then a less sensitive detector would be better.

[bebetxx]

Why an avalanche photodiode? They use to serve for very faint light. Besides being less convenient to use, they would be flooded with light in a normal ambient.

 

In case your design relies on signal processing to extract the echo from ambient light, rather than from heavy filtering on wavelength and direction, then a less sensitive detector would be better.

 

I used a 75 W, 30 ns pulsed laser on infrared. And I tried to use this APD http://www.ebay.com/itm/Photo-Detector-Diode-Silicon-Avalanche-Photo-Diode-SiAPD-/200941931850?pt=LH_DefaultDomain_0&hash=item2ec9128d4a The laser generates 15,000 pulses each second. My goal is to receive the reflected beam from 100 meters for collaborative and non collaborative environments. Is it possible to be flooded by the ambient light? In the first prototype I used a lens with 10 cm.