Abstract

High-speed and low-chirp external optical intensity modulators are important for future high-bit rate transmission systems, because in direct modulation of a laser diode the transmission bandwidth is limited by the large chirp during relaxation oscillation. A GaInAsP/InP optical intensity modulator [1], [2] is one of the candidates for such an external modulator. However it has been recently pointed out that some chirp is caused in such an electroabsorption modulator by the accompanied phase modulation [3]. Until now the dynamic spectral broadening factor α_E which characterizes chirp was obtained only from a ratio of average power in optical sidebands to carrier power under sinusoidal modulation [2]. But it is necessary to evaluate, the chirp under large signal pulse modulation in order to apply to the system. Here we report high-speed and low-chirp characteristics in a newly developed GaInAsP/InP optical intensity modulator.

© 1988 Optical Society of America