NT1210 Lab 4.2: Fiber-optic Cables
Exercise 4.2.1
The light in an SMF cable travels down the center of the fiber parallel to the direction of the fiber in a single path. Can this type of cable be used to transmit and receive bits simultaneously, or does it require one fiber for transmitting and one for receiving? Justify your answer using your textbook and Internet research.

No it cannot transmit and simultaneously receive bits with a single cable. A second cable would be needed for sending bits back. In this case you would need two cables one send bits and second cable receiving bits.
Exercise 4.2.2
What characteristics of fiber-optic cables allow them to be used over longer distances with less risk than copper cable?
The core in single-mode fiber is only approximately 10 times larger than the wavelength of the light it is carrying. This leaves very little room for the light to bounce around. As a result the data carrying light pulses in single-mode fiber are essentially transmitted in a straight line through the core.
Electromagnetic immunity including non-conductivity, Security considerations, decreased attenuation and increased transmission distance, Increased bandwidth potential, Small diameter and weight Long term economics
Exercise 4.2.3
MMF distances can still far exceed copper cable, but MMF cannot match the distance available from the more expensive SMF. What is the reason for the distance limitation with the use of MMF?
Multimode cables are less expensive to operate, install and maintain than single-mode cables. However, they are much more limited in both speed and distance. For instance, the maximum speed of a multimode cable is 10GB, but only up to a distance of 300 meters. Up to 2 kilometers, it is only capable of transmitting at 100Mbit. Beyond that, its transfer speed becomes negligible. This limitation is negated by the fact that its maximum speed is sufficient for the environment that it is most often used in.