optical attenuator for DWDM testing

[hashaari]

I am going to conduct a lab test for DWDM using the ONS 15540 ESPx carrying OC-48 client signal. As the simulated trunk cable is short I need to use attenuator to avoid blowing up the receiver on the OADM. Need your guys help to recommend a brand of attenuator for this kind of application. I am looking at 15 dB for 15XX nm wavelength. Just to confirm, for a pair/span, I need to connect the attenuator at the RX port at both end right? Apreciate the help. Thanks.

[rais]

I am currently using 10db attenuators with 1570 nm. They are from AFL Telecommunications. So far, don't have any problems with them.

http://www.alcoa.com/afl_tele/en/product.asp?cat_id=99&prod_id=159

Yes, connecting attenuators to RX port is the standard most follow. Make sure you also connect Tx of one interface to the Rx of the other.

Hope this helps.

[cjarvisc]

The best application I have found over the past several years has been a JDS Uniphase VOA in the patch cord. These VOAs are adjustable and can simulate many situations. Hope this helps.

[mobious]

You also need to keep in mind that if the distance is to short and the attenuator is to close to the transmitter, the reflected light off the attenuator will be directed back towards the Tx laser. Which will also blow your transmitter. Optimal Rx level is around -18dbm.

[Alexei Andoni]

Any 15 dB attenuator would do the job. 10 dB might be too low for some transponders. If you place a loopback directly on transpnders (without including OADM on the loop) a 20 dB attenuator would be preferable. Just avoid "air-gap" attenuators, as they cause lots of reflections.

Transponders Specifications could be found here:

http://www.cisco.com/univercd/cc/td/doc/product/mels/15540x/hig/xhg_spec.htm

To reduce human error, you might want to place the attenuator on Tx port. Connecting Tx to Tx might damage the transmitter.

Cheers,

Alex