Light is a very good medium for transmission. How the light is created is the problem. Inexpensive toslink based light sources spray the light at the end of the cable at a very wide angle. Inside the cable, the light travels mutiple paths (multi mode) - some light travels directly down the length of the fiber to the destination, other light takes a bouncing path along the length of the cable, arriving later than direct path light. This bouncing (and late arriving) light is carring the same information as the direct light. Hence jitter. Single mode transmission via fiber optics uses a very narrowly focused beam of light at the end of the cable. The light travels a direct path through the fiber without internal reflections - SINGLE MODE - Many of you have seen this option available on higher end transports and processors. It's not the light that is the problem, it's the way it's put on the fiber. The best explination of this is available from the computer networking industry, (network essentials study guides) where fiber optics are used on regular basis.
Why are optical cables jitter prone?
A friend of mine convinced me to purchase an electrical (RCA jack) digital cable for the home theater. He said that even though optical looks neat, it is extremely succeptible to jitter. I thought both kinds were. But, low and behold, I switched to the RCA type and my bass immediately got louder and tighter. Does anyone have a short and sweet explanation as to why? Thanks.