Semiconductor device for rapid optical switch by modulated absorption

An optical cross-connect having at least one semiconductor device comprising:

• a) a photodetector having a low capacitance Cd and a detector absorbing layer for absorbing an optical signal beam;
• b) a modulator having a low capacitance Cm and a modulator absorbing layer for absorbing an optical power beam, said modulator absorbing layer having an electric field-dependent absorption coefficient;
• c) a low resistivity region provided between said photodetector and said modulator such that said electric field-dependent absorption coefficient is altered uniformly and rapidly throughout said modulator absorbing layer on absorption of said optical signal beam;
• and
• d) a high resistivity element in series with said low resistivity region for minimizing a net charge flow to and from said semiconductor device.

A method of operating a semiconductor device for modulating an optical power beam by an optical signal beam, said method comprising:

• a) providing a photodetector having a detector absorbing layer for absorbing said optical signal beam;
• b) providing a modulator having a modulator absorbing layer for absorbing said optical power beam, said modulator absorbing layer having an electric field-dependent absorption coefficient;
• c) providing a low resistivity region between said photodetector and said modulator such that said electric field-dependent absorption coefficient is altered uniformly and rapidly throughout said modulator absorbing layer during absorption of said optical signal beam;
• and
• d) minimizing charge flow to and from said semiconductor device with a high resistivity element in series with said low resistivity region.