Laser for sure, but does not conduct electricity, even used as insulator because of it's ceramiclike atomic structure. Apart from the transmission by light is different from that of electrons in a conductor, while the photons pass at, well, the speed of light, in the electric current only the impulse travels at the speed of light, while an electron only moves at a speed of about 30m/s. It can be understood as a simile with a tube full of peas, if you put one more pea in one side, at the same time another one falls out the other side, although the peas themselves do not move as fast, their momentum travels "at the speed of light". Becaus of this, it will not make much sense to combine both things to increase the bandwidth, quite the contrary, it will only cause interference that decreases it. Fotones are the optimum measure to transmit data. The speed only depends on the contract with your ISP and the capacity of their servers, not on the tecnology of the Fibercable.