This question is on the plot of mode division multiplexing system where it is said capacity crunch can be solved using mdm technique. Now, we know single mode fiber can transmit upto 1Tbps. Now if i use two mode then data transmission capability will be doubled? If the answer is yes, then why people are researching on more and more higher modes.
There are a whole number of different aspects to consider. For starters, the two modes wouldn't experience the same dispersion, they would require different dimensions on the fiber core, something which can only be implemented in newer fibers. They would experience different phase-drift. The in-line amplifiers might not have the adequate gain for the second mode.
Basically, they behave in very different ways. Now, multimode systems do exist, but it is not a matter of simply putting in another mode, the whole system needs to be designed around this.