An 8 km optical fiber link without repeaters uses multimode graded index fiber which has a bandwidth-length product of 400 MHz km. Estimate: (a) the total pulse broadening on the link; (b) the rms pulse broadening on the link. It may be assumed that a return to zero code is used. Bandwidth Distance Product (BDP) Bandwidth Limitations The BDP is the bandwidth of a kilometer of fibre and is a constant for any particular type of fibre. Maximum channel bandwidth B: For non-return-to-zero (NRZ) data format: B = B7/2 For return-to-zero (RZ) data format: Where the maximum bit rate B,= 1/T, and T= bit duration. Bopr *L = B, *L (MHzkm) B = B7 For example, A multimode fibre has a BDP of 20 MHz.km, then:- For zero pulse overlap at the output of the fibre B= 1/2t where t is the pulse width. For MMSF: B, (max) = 1/287, - 1 km of the fibre would have a bandwidth of 20 MHz - 2 km of the fibre would have a bandwidth of 10 MHz Typical B.D.P. for different types of fibres are: For a Gaussian shape pulse:B,S0.2/t,m where t,my is the RMS pulse width. For MMSF: B, (max) 0.2/ tmodal Multimode 6 - 25 MHz.km Single Mode 500 - 1500 MHz.km Graded Index 100 1000 MHZ.km or Br (max) =0.2/ t Total dispersion Prof Z Glussemloov 31