Laserspg2 - Optical Communications Link Various components...

Info iconThis preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
Optical Communications Link Various components that make up an optical telecommunications link i) transmitter, i.e. a laser ii) fiber iii) repeater or amplifier iv) detector i) laser => semiconductor laser diode Advantages: 1) compact 2) extremely efficient (~40%) 3) can be modulated at very high rates (10’s og GHz) The modulator is more often external to the laser. ii) fibers absorption/scattering attenuation coef = γ ~0.5dB/km @ 1550 nm For a single mode fiber the core typically has a radius of a=3-5 μ m and the cladding has a radius of b=80 μ m. The index difference is typically of the order of n=n 1 -n 2 =0.005. Along with the index difference, the other parameter used to characterize an optical fiber is the V# where V = 2 p a l 2 n 1 D n ( ) 1 2 If V<2.405 the fiber will support a single spatial mode. However, if the wavelength is decreased or the core radius is increased the fiber can become multimode. Step-Index vs. Gradient Index Fibers
Background image of page 1
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

Ask a homework question - tutors are online