20 Gbit/s high-performance integrated MQW TANDEM modulators and amplifier for soliton generation and coding

We report on the integration of two InGaAsP-InGaAsP MQW electroabsorption ridge modulators and an amplifier on the same active layer. The two modulators are separated by a 500-μm ridge waveguide optical amplifier, in order to prevent electrical crosstalk, and to compensate for optical losses. The first modulator is used as a soliton generator, and the second codes the generated pulses. The amplifier showed 8.2-dB gain for 120-mA injected current. This allowed a low fiber to fiber insertion loss of 9 dB for the tandem. We present here for the first time to our knowledge, a 20 Gbit/s operation for a tandem-amplifier device, together with transmission experiments.