An optical source has a spectral width of 1300 nm. What type of optical source is it likely to be? A LED B All of these C Coherent source D Wideband source E Laser Diode D is correct why? An optical source has a spectral width of 1300 nm. What type of optical source is it likely to be? Solution Fiber optics are the communication medium through which the signals can be send and also the signals can be received since the signals which have to sent have to be send as fast as possible and this can be achived by this fiber optics. Multimode fiber is one which uses a wideband source by which the signal can be sent at very faster rate.The wider band source has a spectral width of 1300 nm because it has low loss. that is it transmits the wave signal with low loss and with efficient output..