40-Gb/s Low Chirp Electroabsorption Modulator Integrated With DFB Laser

A 40-Gb/s monolithically integrated transmitter containing an InGaAsP multiple-quantum-well electroabsorption modulator (EAM) with lumped electrode and a distributed-feedback semiconductor laser is demonstrated. Superior characteristics are exhibited for the device, such as low threshold current of 20 mA, over 40-dB sidemode suppression ratio at 1550 nm, and more than 30-dB dc extinction ratio when coupled into a single-mode fiber. By adopting a deep ridge waveguide and planar electrode structures combined with buried benzocyclobutene, the capacitance of the EAM is reduced to 0.18 pF and the small-signal modulation bandwidth exceeds 33 GHz. Negative chirp operation is also realized when the bias voltage is beyond 1.6 V.

National Natural Science Foundation of China 90401025 60736036607060096077702160702006National 973 Program of China 2006CB604901 2006CB604902 National 863 project 2006AA01Z256 2007AA03Z419 2007AA03Z417 The work was supported by the National Natural Science Foundation of China (Grant 90401025, 60736036, 60706009, 60777021,60702006), by the National 973 Program of China (Grant 2006CB604901, 2006CB604902), and by the National 863 project (Grant 2006AA01Z256, 2007AA03Z419, 2007AA03Z417).