TOSLink (Toshiba-Link), an optical fiber connection system, was first developed by Toshiba for its CD players. It rapidly became the de facto benchmark for other CD player companies. However, today, its usage is not limited to CD players. It is used for factory automation, car audio and navigation system, office automation, and so on.

TOSLink is essentially a data transmission system that makes use of optical signals, in place of electrical signals. It is much more reliable compared to electrical data transmission, as electromagnetic noise or distortion has no effect on the digital transmission of data or sound. Nor does it emit any electromagnetic noise.

TOSLink consists of the following components:

  • Transmission module
    Converts electrical signals into optical signals.
  • Receiving module
    Re-converts optical signals into electrical signals.
  • Optical fiber cable
    Acts as the physical transmission line.
  • Optical connectors
    Connects the transmission and receiving modules to the optical fiber cable.

TOSLink and its physical attributes

A basic TOSLink cable uses low-cost 1 mm plastic optical fibre. However, depending on the required bandwidth and application, TOSLINK also uses better quality multi-strand plastic optical fibers or quartz glass optical fibers.

Optical fiber cable consists of two sections. The center of the cable is known as the core, and the outer section is known as the cladding. The refractive index if the core is greater than of the cladding. This kind of assembly effectively ensures that when optical rays are transmitted at an angle to the axis of the cable, it is reflected at the boundary between the core and cladding. This will lead to optical rays being transmitted longitudinally throughout the core.

The types of optical fiber are as follows:

  • All-plastic fiber (APF) – used for short distance data transmission.
  • Plastic-cladding silica fiber (PCF) – used for middle distance data transmission
  • Silica fiber – used for long distance transmission.