| 摘要 |
An optical pulse train generator ( 2 ) for use in the transmission of high speed optical data in a return-to-zero (RZ) signalling format is described. The generator ( 2 ) comprises a light source ( 4 ) operable to produce an unmodulated output; an electro-optic interferometric optical modulator ( 6 ) for intensity modulating the unmodulated optical output in dependence on an sinusoidal drive voltage (v<SUB>drive</SUB>) to produce a modulated optical signal, wherein the modulator ( 6 ) has an optical transmission versus drive voltage characteristic which is sinusoidal in form and wherein the modulator ( 6 ) is operable about a point of minimum optical transmission of said characteristic and said drive voltage has a amplitude (V<SUB>drive</SUB>) which exceeds one cycle (V<SUB>pi</SUB>) of said characteristic such that the modulated optical signal is non-sinusoidal; and optical pulse shaping means ( 8, 10, 12 ) for aligning the phase of the frequency components of said modulated optical signal to produce an optical pulse train in which the pulses are substantially transform limited. |
