Singlemode UPC is blue and singlemode APC is green. Fiber optic cables come in a variety of colors, and these colors aren't just for aesthetics – they actually indicate the type of fiber inside the cable. OM5 is the newest type of multimode fiber, designed for SWDM (Shortwave Wavelength Division Multiplexing) applications. What Do different fiber strand colors represent? In. Fiber optic color coding is an essential part of managing and working with fiber optic cables and components.