A 8x8 port multimode fiber, transmissive star coupler has 0 dBm of optical power launched into a single input port. The average measured optical power at each output port is 15 W. Calculate the total loss incurred by the star coupler and the average insertion loss through the device. (8) 3.3 The Fresnel reflection at a butt joint with an air gap in a multimode step-index fiber is 0.46 dB. Determine the refractive index of the fibre core. (5)