All-optical, high contrast GaAlInAs multiple quantum well asymmetric reflection modulator at 1.3 μm

A high contrast, low intensity GaAlInAs/AlInAs multiple quantum well asymmetric Fabry-Perot reflection modulator for operation at 1.3 μm has been demonstrated. The reflection modulator takes advantage of the large absorptive and refractive nonlinearities associated with saturating the heavy-hole exciton resonance. We achieve an on/off contrast ratio in excess of 1000:1 (30 dB) and an insertion loss of 2.2 dB at a pump intensity of 30 kW/cm², corresponding to a carrier density of 4.5×10¹⁷ cm^-3. The modulator was demonstrated to have a large operating bandwidth, achieving an on/off contrast ratio of greater than 100:1 over a 5 nm optical band. The operating speed of the modulator was measured and found to approach 1 GHz.