A light source needs the following characteristics is given below :
Characteristics of Light source for communication:
- It must be possible to operate the device continuously at a variety of temperatures for many years.
- It must be possible to modulate the light output over a wide range of modulating frequencies.
- For fiber links, the wavelength of the output should coincide with one of the transmission windows for the fiber type used.
- To couple a large amounts of power into an optical fiber device the emitting area should be very small.
- To reduce material dispersion in an optical fiber link, the output spectrum should be too narrow.
- The optical output power must be directly modulated by varying the input current to the device.
- High coupling efficiency.
- Low weight and low cost.
- Better linearity to prevent harmonics and inter-modulation distortion.
- High optical output power.
- High reliability.
- The power requirement for its operation must be low.
- The light source must be compatible with the modern solid-state device.