Modulator and method of modulating optical carrier with clock signal before or after the carrier is modulated with data pulse

Abstract From the Canadian patent

In an optical transmitter which modulates a continuous-wave optical carrier with an electrical data pulse, the carrier is modulated with a clock signal having 1/2n (where n is an integer equal to or greater than unity) of the frequency of a fundamental sinusoidal component of the data pulse so that the modulated carrier contains at least a center frequency spectral component. On the modulated optical carrier a filtering operation is performed so that the filtered carrier contains a carrier frequency component and first sideband components. Before or after the clock modulation is performed, the data pulse is used to perform data modulation on the optical carrier.