MONOLITHIC SEMICONDUCTOR SOLITON TRANSMITTER

A monolithic soliton transmitter is fabricated using the PPro-II process in the InGaAsP material system by integrating an electro-absorption modulator with an extended-cavity laser. The laser cavity comprises a 700-mu m-long active region, which consists of 6 strain-compensated multiple quantum wells, a 8100-mu m-long passive buried-rib waveguide section, and a Bragg reflector with a length of 250 mu m. Mode-locking of the laser section results in 8-ps pulses at a repetition rate of 4.9 GHz. The time-bandwidth product is 0.30. Using the partially reflecting grating as one of the laser mirrors allows for integration of an electro-absorption modulator as a monolithic but extra-cavity data encoder. The modulator is fabricated by growing a 2000 Angstrom thick 1.46-mu m quaternary layer on top of the waveguiding layers. At a 4.9-Gb/s data rate, an extinction ratio of 20 dB is measured at a signal wavelength of 1565.4 nm.