A fiber optic transmitter comprising: a digital driver adapted to adjust the rise time and fall time of a digital input signal; an optical source adapted to receive the digital signal and produce a frequency modulated optical signal; and an optical spectrum reshaper adapted to convert the frequency modulated optical signal to an amplitude modulated optical signal. A method for transmitting an optical signal through a fiber comprising: receiving a digital input signal; adjusting the rise time and fall time of the digital input signal so as to produce an adjusted digital input signal; passing the adjusted digital input signal to an optical source so as to produce a frequency modulated optical signal; passing the frequency modulated optical signal through an optical spectrum reshaper so as to convert the frequency modulated optical signal to an amplitude modulated optical signal; and passing the amplitude modulated signal into the fiber.