Wide optical bandwidth asymmetric Fabry-Perot reflection modulator using the quantum confined Stark effect

A normally on, high-performance quantum confined Stark effect asymmetric Fabry-Perot reflection modulator with enhanced optical bandwidth is reported. The wide optical bandwidth is achieved by utilizing the variation in refractive index in the vicinity of the heavy-hole exciton. The nominal operating wavelength is set in the region where the on-state refractive index starts to increase and allows the Fabry-Perot resonance condition to be maintained over a wide wavelength range. An optical bandwidth of 5 nm is achieved for an operating voltage of 7 V, insertion loss 55% and contrast ratio > 15 dB, and 7 nm if the contrast ratio is relaxed to >10 dB. These values are twice as wide as previously reported for a quantum confined Stark effect modulator structure, and correspond to an operating temperature range of 25 degrees C compared to 10 degrees C for conventional structures. (C) 1998 American Institute of Physics. [S0021-8979(98)01022-6]