Abstract
We report systematic modelling of 1310 nm InGaAsP/InP electroabsorption modulators. The modulator is a reverse
biased p-i-n diode, in which the MQW structure is composed of several InGaAsP/InGaAsP quantum wells. By a 3D
finite element software PICS3D, we have comprehensively investigated the internal physical mechanism of the
modulator, which includes the red shift of the absorption edge with the reverse bias and the absorption intensity, which
could be derived from the normalized overlap integral between the energy levels for the electrons and the holes. The
absorption spectrum on wavelength and the reverse bias voltage is analyzed, which provide us with both the extinction
ratio and the transimision loss for a special operating wavelength. Key design parameters such as barrier height and
quantum well width are optimized for extinction ratio, and confirmed by parallel experimental studies. What’s more, the
RF performance has been investigated in detail. The junction capacitance, the series resistance and the parasitic
capacitance (mostly the bonding pad) are studied systematically. A ridge structure model is analyzed for high speed
performance, in which the important parameters, such as the ridge width, the cavity length, the area of the bonding pad
and the thickness of polyimide (or BCB) under the bonding pad, are optimized for over 20GHz 3dB bandwidth. The
cavity length is optimized by making compromise between the extinction ratio and the RF performance. In conclusion,
the design parameter space of the 1310nm InGaAsP/InP EAM have been systematically explored. Our work should
provide a firm basis for 1310nm InGaAsP/InP EAM device design optimization for optical datacom applications.
