Strand fiber is a single strand of Glass (optical fiber) used to send Data in both directions. Data is sent one direction on one Wavelength and is sent the opposite direction on a different wavelength.
Working with strand fiber has some benefits. It increases Network capacity. For example IF you have a 6 strand Cable then you are able to communicate/transmit on all six lines. If you are transmitting and receiving on separate fibers, then you will only have three lines of communication/transmission available.
Single strand Fiber applications are more cost effective then traditional means. Also, they are less susceptible to connection errors because there are fewer connections.