Hi Aaron,
Are there situations when angled connectors are not to be used? Are they 'safe' or even recommended for any kind of DWDM application?
To my knowledge APC is always better than PC connectors. APC are used to eliminate back reflections. Due to the angled connector reflections are sent mostly towards the cladding and not the core and therefore. The effecs of back reflections are great. Read this http://documents.exfo.com/appnotes/anote044-ang.pdf I can not see why APC connectors are not to be used, even with DWDM. The only problem with APC is that there are different kinds of angles (8 degrees and 9 degrees) and polishments of the tip. When using the wrong connectors (for example a 8 degrees against a 9 degrees in a coupler) you will introduce more loss. This would be the reasons why some people fear to use APC. regards, Igor