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An optical fibre has a core diameter of 9 µm, a cladding diameter of 150 μm, a core refractive index of 1.465 and a cladding refractive index of 1.46. Is this a single-mode fibre at 1.3 µm wavelength? [5 marks] (b) A 2 mW laser operating at a bit rate of 500 Mb s1 has a line width of 4 nm. The light is coupled into a single-mode fibre with a coupling loss of 3 dB. The fibre has a chromatic dispersion parameter of 12 ps nm-¹ km-¹ and an attenuation of 0.3 dB km-1. The output coupling loss is 3 dB and the receiver has a sensitivity of -35 dBm. Assuming a 4 dB systems margin is required. calculate the maximum link length. Show all of your calculations and state any approximations or assumptions you have made in your calculations. Suggest what modifications could be made to this link in order to double its length. [8 marks]