This may be a silly question, but I don't understand why the bandwidth is so low. I understand the latency will be high, since you're limited by the speed of l

This may be a silly question, but I don't understand why the bandwidth is so low. I understand the latency will be high, since you're limited by the speed of light; but wouldn't you be able to get more bandwidth just by increasing the spectrum of light used, as well as the baud of the transmitter/receiver?