25-Gb/s Laser Modulated EML With High Output Power

Using a conventional electro-absorption modulated laser (EML) device, with a dual-drive scheme, we show increased output power before modulator saturation effects degrade the signal quality. Both the laser and modulator section of the EML are driven simultaneously to generate a 25 Gb/s intensity modulated optical signal. With this dual-drive scheme we achieved a modulated output power of +7 dBm while maintaining a high extinction ratio (≥ 9 dB) and sufficient mask margin. Since the operating wavelength was 1301 nm, the optical path penalty was negligible after a 20 km fiber link. Compared with a conventional EML, in which the laser is continuously on and only the EAM is driven, we improved the mean modulated output power by 3.2 dB. With the proposed driving scheme, conventional simple and low-cost EMLs could be used to meet the requirements of high loss budget links such as those in passive optical network applications.