Abstract

Recent high-speed optical transmission systems proposed for operation above 1 Gbit/s using the 1.55-μm wavelength have called for repeater spacings >80 km. However, at this wavelength, with direct intensity modulation with semiconductor lasers, the signal waveform is excessively degraded by fiber chromatic dispersion.¹ This is caused by chirping, and worsens as the transmission rate increases. Although this can be remedied with fiber having zero dispersion at 1.55 μm, there is a great economic incentive to use the fiber with zero dispersion at 1.3 μm, already in place. For this reason, we have developed a compact and low-chirp 2.5-Gbit/sec optical transmitter (E/O) module using a LiNbO₃ Mach-Zehnder (LN) modulator. Figure 1 is a block diagram of the 2.5-Gbit/s LN-E/O module.

© 1992 Optical Society of America