Slow wave optical waveguide for velocity matched semiconductor modulators

A semiconductor modulator for modulating an optical wave with an RF signal, said modulator comprising:

• a substrate;
• an N-type layer deposited on the substrate;
• a semiconductor intrinsic layer deposited on the substrate and in contact with the N-type layer, said intrinsic layer containing an optical waveguide, said intrinsic layer, including first and second diffraction gratings positioned at opposing sides of the intrinsic layer, said first and second diffraction gratings including etched holes in the intrinsic layer that extend in a direction perpendicular to the propagation direction of the optical wave;
• a P-type layer deposited on the substrate and in contact with the intrinsic layer;
• and
• a first electrode in electrical contact with the N-type layer and a second electrode in electrical contact with the P-type layer, said first and second electrodes receiving the RF signal and said first and second diffraction gratings slowing the optical wave to match its speed to the speed of the RF signal in the electrodes.

A semiconductor modulator for modulating an optical wave with an RF signal, said modulator comprising:

• a substrate;
• an N-type layer deposited on the substrate;
• a semiconductor intrinsic layer deposited on the substrate and in contact with the N-type layer, said intrinsic layer containing an optical waveguide, said intrinsic layer including first and second Bragg diffraction gratings positioned at opposing sides of the intrinsic layer;
• a P-type layer deposited on the substrate and in contact with intrinsic layer;
• and
• a first electrode in electrical contact wit the N-type layer and a second electrode in electrical contact with the P-type layer, said first and second electrodes receiving the RF signal and said first and second diffraction gratings slowing the optical wave to match its speed to the speed of the RF signal in the electrodes.

A semiconductor modulator for modulating an optical wave with an RF signal, said modulator comprising:

• a substrate;
• an N-type layer deposited on the substrate;
• a semiconductor intrinsic layer deposited on the substrate and in contact with the N-type layer, said intrinsic layer containing an optical waveguide, said intrinsic layer including first and second two-dimensional diffraction gratings positioned at opposing sides of the intrinsic layer;
• a P-type layer deposited on the substrate and in contact with the intrinsic layer;
• and
• a first electrode in electrical contact with the N-type layer and a second electrode in electrical contact with the N-type layer, said first and second electrodes receiving to RF signal and said first and second diffraction gratings slowing the optical wave to match its speed to the speed of the RF signal in the electrodes.

A semiconductor modulator for modulating an optical wave with an RF signal, said modulator comprising:

• a substrate;
• an N-type InP layer deposited on the substrate;
• a semiconductor intrinsic InP layer deposited on the substrate and in contact with the N-type InP layer, said intrinsic InP layer containing an optical waveguide, said intrinsic InP layer including first and second diffraction gratings positioned at opposing sides of the intrinsic InP layer;
• a P-type InP layer deposited on the substrate and in contact with the intrinsic InP layer;
• and
• a first electrode in electrical contact with the N-type InP layer and a second electrode in electrical contact with the P-type InP layer, said first and second electrodes receiving the RF signal and said first and second diffraction gratings slowing the optical wave to match its speed to the speed of the RF signal in the electrodes.

A traveling wave semiconductor optical modulator for modulating an optical signal with an RF signal, said modulator comprising:

• a substrate;
• an N-type layer deposited on the substrate;
• a semiconductor intrinsic layer deposited on the substrata and in contact with the N-type layer, said intrinsic layer containing an optical waveguide, said intrinsic layer including two-dimensional Bragg diffraction gratings positioned at opposing sides of the waveguide, said diffraction gratings causing the optical signal to propagate down the waveguide in a zig-zag manner so as to increase its propagation length through the waveguide, said first and second diffraction gratings including etched holes that extend in a perpendicular direction to the propagation direction of the optical signal;
• a P-type layer deposited on the substrate and in contact with the intrinsic layer;
• and
• a first electrode in electrical contact with the N-type layer and a second electrode in electrical contact with the P-type layer, said first and second electrodes defining a transmission line, said first and second electrodes receiving the RF signal, wherein the first and second diffraction gratings cause the optical signal to have a speed that matches the speed of the RF signal in the transmission line.

A method of modulating an optical signal with an RF signal, said method comprising the steps of:

• providing a PIN semiconductor modulator structure, said step of providing the modulator structure including forming first and second Bragg diffraction gratings in an intrinsic layer of the structure where the intrinsic layer contains an optical waveguide, said step further including forming holes in the intrinsic layer that extend in a direction perpendicular to the propagation direction of the optical signal;
• propagating the optical signal down the waveguide so that it interacts with the first and second diffraction gratings to cause the optical signal to propagate in a zig-zag manner;
• and
• applying an electric field across the waveguide to modulate the optical signal, where the speed of the electric field along the waveguide is matched to the speed of the optical signal.