We present the first 40-Gb/s widely tunable electroabsorption modulator (EAM)-based transmitters. The sampled-grating Distributed Bragg Reflector (SG-DBR) laser/EAM devices were fabricated using a multiple-band-edge-quantum-well-intermixing (QWI) technique, which requires only simple blanket regrowth and avoids disruption of the axial waveguide. Devices were fabricated from two different multiple quantum well (MQW) active-region designs for direct comparison. The SG-DBR lasers demonstrated 30 nm of tuning with output powers up to 35 mW. The integrated QW EAMs provided 3-dB optical modulation bandwidths in the 35–39 GHz range, low-drive voltage (1.0–1.5 VPtoP), and low/negative-chirp operation. Bit-error-rate measurements at 40 Gb/s demonstrated 0.2–1.1 dB of power penalty for transmission through 2.3 km of standard fiber.
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