60 nm wavelength range polarization-insensitive 1.55 mu m electroabsorption modulator using tensile-strained pre-biased multiple quantum well

We studied theoretically and experimentally an InGaAs/InAlAs/InP polarizati on-insensitive multiple quantum well (MQW) electroabsorption (EA) modulator operating over a very wide wavelength range in 1.55 mu m wavelength region . One of the simplest possible potential-tailored quantum well, "pre-biased " quantum well (PBQW) is used to achieve wide-wavelength polarization insen sitivity. PBQW is basically a rectangular quantum well with a thin barrier inserted near one edge of well. This thin barrier effectively introduces "p re-bias" to a rectangular quantum well and the same amount of Stark shift i s achieved for electron-heavy hole and electron-light hole transition energ ies. By incorporating tensile strain into PBQW, polarization-insensitive mo dulation is achieved over 60 nm wavelength range, from 1510 nm to 1570 nm. This MQW-EA modulator plays an important role in wavelength division multip lexing (WDM) transmission and switching systems.