i have to connect two LC/APC male connector plugs. Currently i only have blue LC-LC couplers on stock.
Due to analogue RF-Overlay signals that are transmitted via this link, the quality of the connection is important here.
Is there a difference between LC/APC and LC/PC couplers? In my understanding the "angled" part is only defined by the tip of the male LC connector, so it should be irrelevant if i use a green or a blue coupler. Am i right or is there a difference in real world?
PC or SPC stands for (super) physical contact: the fiber cores touch each other. The better the contact the lower the attenuation and reflection values.
Angled physical contact APC connectors have an contact face that is tilted (usually by 8°) out of the perpendicular. The angle reduces reflection to near zero, especially when there is no termination - this is usually required for unused PON links or for high-power links. APC can have slightly higher insertion attenuation than SPC but has far superior reflection parameters.
Do not ever mix the - usually green - APC connectors with - usually blue - SPC connectors: the angle very easily damages the surface on one or both sides! Additionally, the resulting air gap cripples the connection anyway.
The couplers are the same, because the connector housings are the same. But still, you can only connect pc to pc, so you should use a blue coupler in that case, and only use green couplers with apc to apc connections. Why? Because the next technician that comes by might be confused, only look at the coupler, etc, and mess it up.