One of the many beautiful things about fiber optic technology is that most cable types and sizes have been standardized since the late 1980s. This has made fiber optic networks very easy to upgrade or add additional connectivity, since fiber links made by cable manufacturer XYZ can be readily connected to new fiber links made by company ABC.
What is important to note when planning to connect to older existing fiber optic links is you must check the size of the core and cladding of the existing cable, and match up the right size of the new cable so there is minimal optical loss at a splice or connector junction. In most cases fiber cables have their contents printed on the outside of the cable every few feet or so. A fiber cable that is labeled “6 X 62.5/125” indicates that the cable contains six strands of 62.5 core multimode fiber, which was the standard type of multimode installed until about 2002 for distances less than two miles. At that time the need for multimode fiber to work optimally with laser transmitters saw the rise of 50/125 multimode which is “laser optimized.” Since the early 2000s most multimode fiber installed has been the 50-micron stuff, which will be labeled “OM3” or “OM4,” indicating its capability to transmit large bandwidth.