OPTICAL BANDWIDTH CONSIDERATIONS IN P-I-N MULTIPLE-QUANTUM-WELL MODULATORS

We investigate the optical bandwidth of p-i(multiple quantum well [MQW])-n modulators employing various MQW designs. The optical bandwidth translates directly into an operating temperature range due to the shift of the band gap with temperature. We find that although greater maximum modulation may be obtained with narrow (similar to 90 Angstrom) quantum wells operating below the band edge (absorption increases with field), uniform large performance may be obtained over a larger bandwidth using wider (similar to 110 Angstrom) quantum wells operating at the exciton (absorption decreases with field). We obtain a usable bandwidth of 7.7 nm, which translates into a operating temperature range of 27 degrees C.