The signal injection efficiency of electroabsorption modulator integrated lasers (EMLs) is improved to suit 10-Gb/s applications. For a typical EML module design with a conventionally designed 50-Ω signal feeder to meet the input return loss requirement for 10-Gb/s applications, a reduction in device capacitance of the electroabsorption modulator (EAM) section by 65% from its typical value is necessary. By optimizing the characteristic impedance of the signal feeder, the required 65% reduction in device capacitance of the EAM section is reduced to 45%, which would naturally lead to enhanced extinction ratio and optical output power. With the addition of a series 5-Ω thin-film resistor along the signal feeder, the device capacitance reduction of the EAM section is further reduced to approximately 33% of the typical value.
© 2006 IEEE
Cheng Guan Lim, "The Effect of Signal-Feeder Characteristic Impedance on the Signal Injection Efficiency of Electroabsorption Modulator Integrated Lasers," J. Lightwave Technol. 24, 3835-3841 (2006)