Chirp Parameter of Electroabsorption Modulators with InGaAsP Intrastep Quantum Wells

Abstract

The chirp parameter of electroabsorption modulators (EAMs) with intrastep quantum wells (IQWs) based on the InGaAsP material system is investigated theoretically. The chirp parameter of the IQW EAM, calculated by using the Kramers-Kronig relation, shows a discontinuity at a low voltage due to the blue shift in transition energy. Once the red shift is initiated, the chirp of the IQW EAM is similar to that of the conventional quantum-well (QW) EAM. Comparison with the conventional QW EAM shows that the IQW EAM could still be operated under high optical power without the compromise in chirp and absorption loss.

The design of electroabsorption modulators with negative chirp and very low insertion loss

“…It mainly depends on waveguide scattering loss, free carrier absorption loss and EA material residual absorption loss OE20 . Insertion loss due to residual absorption, IL, is given by IL D 4:343 ˛0L (dB); (12) where ˛0 is the static electroabsorption coefficient in the ON state. The insertion loss increases very quickly as the waveguide length increases.…”

Reduction in Escape Times of Photogenerated Charge Carriers with Asymmetric Intrastep Quantum Wells and Subsequent Improvement in Saturation Optical Intensity

“…1) Chirp of the IQW EAM was also calculated to show that there exists a discontinuity near the low voltage, showing the effect of blue shift in the transition energy. 8) In this study, the effect of a step barrier on the saturation optical properties is quantitatively investigated by calculat-ing the escape times and saturation optical intensities of a conventional QW and an IQW. To the author's knowledge, this is the first attempt to elucidate the reduction in escape time due to the step barrier in the QW and the subsequent increase in saturation optical intensity.…”