1.5 .mu.m wavelength asymmetric fabry-perot modulator with negative chirp

An asymmetric Fabry-Perot modulator (AFPM) for amplitude modulating an incident optical input signal having an operating wavelength in the region of 1.5 .mu.m in response to an external modulating signal, said modulator comprising:

• a top reflector surface upon which said input signal is incident;
• a bottom reflector having high reflectivity;
• and
• electro-absorption material disposed between said top reflector surface and said bottom reflector, the absorption of said electro-absorption material being varied in response to said external modulating signal, the magnitude of the total optical output signal from said top reflector surface being determined by the reflectivity of the top reflector surface, the reflectivity of the bottom reflector and the absorption in said electro-absorption material;
• characterized in that
• said electro-absorption material comprises an Al.sub.x In.sub.y Ga.sub.1-x-y As multiple quantum well structure having a sufficient number of periods to achieve a matching condition output in which an approximately zero magnitude output signal is produced when the magnitude of said modulating signal is at an associated matching condition voltage, said multiple quantum well structure comprising Al.sub.x In.sub.y Ga.sub.1-x-y As barriers of thickness larger than 30 .ANG. and Al content x.gtoreq.0.12, and Al.sub.x In.sub.y Ga.sub.1-x-y As wells of thickness between 20 .ANG. and 500 .ANG. and Al content x.ltoreq.0.10.