(This is no April Fool’s question.) What do you think if someone were to advise you that, at the right transmission rate, I could transmit through SM into the patch panel (P/P), but go across MM fiber and back into SM P/P…or words to this affect?
Have others had luck mixing like this, or is it not recommended by the industry. This is for a professional application, but I do not own the fiber network. I am a bit surprised someone would recommend this…unless there are times when good practice says it can be permissible.
P.S. I know one does not really “send” SM or MM. Rather, “SM” or “MM” is a characteristic determined by the fiber optic medium itself. However, I believe you can still understand what is being asked above.
What I want to know is how you can ask such a technical question about fiber communications, but at the same time be utterly unaware what Firefox is or what client server means.
Ah, young grasshopper, you quoteth me well; yet, the world is full of many anamolies and contradictions, is it not? How did you get all your answers had you not thought to ask the questions? Glad I make you wonder. It opens the mind.
You can use SM transceivers with MM fiber, but your distance x bandwidth will be much lower than with SM fiber. The problem is just that it’s a waste of money for the SM equipment.
IIRC, at one time (still now?) SM was much much more expensive than MM.
2 problems; SM has a much smaller core in the initial transmit unit; then that signal goes into a core about 5 times the diameter; at the other end, it goes into a receiver unit with a feed only 1/5 diameter, or 1/25 the area. Patch cords just butt ends agianst each other.
So theoretically, yes, you can mix and macth fibers. We originally laid in a network with some 50/125MM core, then went to 62.5/125MM and use patch cords between the two with minimal problems, especially back in the 10Mbps ethernet days. You just lose a bit of power in the signal, and hence distance.
As for SM vs MM - SM should be good for 10’s of km, while MM was usually good for 1.5km (IIRC). You certainly won’t get SM distances anyhow on MM cable.
The cladding of fiber optic causes the signal to bounce back into the fiber if it strikes an edge. This means the path of signal bouncing back and forth side to side is longer that that of straight through direct signal. Over distance, this turns a sqare wave into a fuzzy sloped curve. When the distance difference reaches near 1/2 wave, the signals will interfere and cancel each other. This sets the usable distance. I don’t recall the exact difference between the SM and MM transmitters, other than the wavelengths (and signalling? One’s a laser, the other LED?) were different; one could not detect the other. You sure as heck won’t get SM distances on a multimode fiber, and probably won’t get even MM distances using SM equipment; but in a pinch, you could probably use a MM patch cord to connect two SM devices and get a connection.
There should be no problem launching from a single mode fiber into multimode fiber. The problem is in the other direction. The original optical mode will typically couple into multiple modes of the MM fiber, with little if any control over which modes. When you couple in the other direction, you have no way of controling how much of the power from the original mode will couple into the single mode fiber. Worse yet, the coupled power will vary with temperature and with motion of the fiber. If you have plenty of loss budget to spare, it might work just fine. If not, it might work when you first set it up and fail later.
Others have already addressed the limited bandwidth of multimode fiber, which is caused by the dispersion between modes, but this should not be a big problem it you are only using MM in the patch panel.
Bottom line, it might work, but it is unreliable and bad practice.