摘要:
A modulating retroreflector system includes a modulating retroreflector having a plurality of multiple quantum well modulator pixels and at least one transimpedance amplifier. The transimpedance amplifier receives a photocurrent generated by at least one of the plurality of modulator pixels. Each pixel is capacitively coupled to a current driver, which applies a high frequency digital electrical signal to the pixel when the voltage at the output of the transimpedance amplifier exceeds a threshold value. The modulated output of the retroreflector is reflected toward the source of the received optical beam. The system activates high frequency current drivers for only the illuminated pixels, eliminating the need for a separate angle of incidence sensor and reducing power requirements. A low frequency FSK signal can be superimposed on the DC optical interrogation beam and recovered as the unfiltered output of the transimpedance amplifier, to provide simultaneous bidirectional communication without a half-duplex communication protocol.
摘要:
A modulating retroreflector system includes a modulating retroreflector having a plurality of multiple quantum well modulator pixels and at least one transimpedance amplifier. The transimpedance amplifier receives a photocurrent generated by at least one of the plurality of modulator pixels. Each pixel is capacitively coupled to a current driver, which applies a high frequency digital electrical signal to the pixel when the voltage at the output of the transimpedance amplifier exceeds a threshold value. The modulated output of the retroreflector is reflected toward the source of the received optical beam. The system activates high frequency current drivers for only the illuminated pixels, eliminating the need for a separate angle of incidence sensor and reducing power requirements. A low frequency FSK signal can be superimposed on the DC optical interrogation beam and recovered as the unfiltered output of the transimpedance amplifier, to provide simultaneous bidirectional communication without a half-duplex communication protocol.
摘要:
An electro-optic device with a doped semiconductor base and a plurality of pixels on the semiconductor base. Pixels include oppositely doped semiconductor layer and a top electrode formed on the oppositely doped semiconductor layer. The top electrode has a grid pattern with at least one busbar and a plurality of fingers extending from the busbar, and spacing between the fingers decreases with distance from the bondpad along the busbar. Each pixel can also include a multiple quantum well formed on the semiconductor base. The top electrode shape produces an approximately uniform lateral resistance in the pixel. An embodiment is a large area modulator for modulating retro-reflector systems, which typically use large area surface-normal modulators with large lateral current flow. Uniform resistance to each part of the modulator decreases location dependence of frequency response. A chirped grid electrode balances semiconductor sheet resistance and metal line resistance components of the series resistance.
摘要:
A device includes a waveguide grating out-coupler, and a tunable uniform phase shifter communicating with the waveguide grating out-coupler. The tunable uniform phase shifter steers a Hat phase front along a first angle in a first plane. Optionally, the waveguide grating out-coupler includes a modulated refractive index and a physical grating period. The tunable uniform phase shifter controls the refractive index, thereby controlling an effective grating period. The grating period relates to die modulated refractive index, and the physical grating period. Optionally, the tunable uniform phase shifter includes a first thermo-optic phase shifter, a first electro-optic phase shifter, or a first micro-electro-mechanical system index perturbation phase shifter. Optionally, the tunable linear gradient phase shifter communicates with the waveguide grating out-coupler and steers a beam along the flat phase front along a second angle in a second plane, which is perpendicular to the first plane.
摘要:
An electro-optic device with a doped semiconductor base and a plurality of pixels on the semiconductor base. Pixels include oppositely doped semiconductor layer and a top electrode formed on the oppositely doped semiconductor layer. The top electrode has a grid pattern with at least one busbar and a plurality of fingers extending from the busbar, and spacing between the fingers decreases with distance from the bondpad along the busbar. Each pixel can also include a multiple quantum well formed on the semiconductor base. The top electrode shape produces an approximately uniform lateral resistance in the pixel. An embodiment is a large area modulator for modulating retro-reflector systems, which typically use large area surface-normal modulators with large lateral current flow. Uniform resistance to each part of the modulator decreases location dependence of frequency response. A chirped grid electrode balances semiconductor sheet resistance and metal line resistance components of the series resistance.
摘要:
A device includes a waveguide grating out-coupler, and a tunable uniform phase shifter communicating with the waveguide grating out-coupler. The tunable uniform phase shifter steers a flat phase front along a first angle in a first plane. Optionally, the waveguide grating out-coupler includes a modulated refractive index and a physical grating period. The tunable uniform phase shifter controls the refractive index, thereby controlling an effective grating period. The grating period relates to the modulated refractive index, and the physical grating period. Optionally, the tunable uniform phase shifter includes a first thermo-optic phase shifter, a first electro-optic phase shifter, or a first micro-electro-mechanical system index perturbation phase shifter. Optionally, the tunable linear gradient phase shifter communicates with the waveguide grating out-coupler and steers a beam along the flat phase front along a second angle in a second plane, which is perpendicular to the first plane.
摘要:
An electro-optic device with a doped semiconductor base and a plurality of pixels on the semiconductor base. Pixels include oppositely doped semiconductor layer and a top electrode formed on the oppositely doped semiconductor layer. The top electrode has a grid pattern with at least one busbar and a plurality of fingers extending from the busbar, and spacing between the fingers decreases with distance from the bondpad along the busbar. Each pixel can also include a multiple quantum well formed on the semiconductor base. The top electrode shape produces an approximately uniform lateral resistance in the pixel. An embodiment is a large area modulator for modulating retro-reflector systems, which typically use large area surface-normal modulators with large lateral current flow. Uniform resistance to each part of the modulator decreases location dependence of frequency response. A chirped grid electrode balances semiconductor sheet resistance and metal line resistance components of the series resistance.
摘要:
An electro-optic device with a doped semiconductor base and a plurality of pixels on the semiconductor base, each pixel including: a multiple quantum well formed on the semiconductor base, an oppositely doped semiconductor layer on the multiple quantum well, and a top electrode on the semiconductor layer, the top electrode shaped to produce an approximately uniform lateral resistance in the pixel. An embodiment is a large area modulator for modulating retro-reflector systems, which typically use large area surface-normal modulators with large lateral current flow. Uniform resistance to each part of the modulator decreases location dependence of frequency response. A chirped grid electrode balances semiconductor sheet resistance and metal line resistance components of the series resistance.
摘要:
An electro-optic device with a doped semiconductor base and a plurality of pixels on the semiconductor base. Pixels include oppositely doped semiconductor layer and a top electrode formed on the oppositely doped semiconductor layer. The top electrode has a grid pattern with at least one busbar and a plurality of fingers extending from the busbar, and spacing between the fingers decreases with distance from the bondpad along the busbar. Each pixel can also include a multiple quantum well formed on the semiconductor base. The top electrode shape produces an approximately uniform lateral resistance in the pixel. An embodiment is a large area modulator for modulating retro-reflector systems, which typically use large area surface-normal modulators with large lateral current flow. Uniform resistance to each part of the modulator decreases location dependence of frequency response. A chirped grid electrode balances semiconductor sheet resistance and metal line resistance components of the series resistance.
摘要:
An electro-optic device with a doped semiconductor base and a plurality of pixels on the semiconductor base, each pixel including: a multiple quantum well formed on the semiconductor base, an oppositely doped semiconductor layer on the multiple quantum well, and a top electrode on the semiconductor layer, the top electrode shaped to produce an approximately uniform lateral resistance in the pixel. An embodiment is a large area modulator for modulating retro-reflector systems, which typically use large area surface-normal modulators with large lateral current flow. Uniform resistance to each part of the modulator decreases location dependence of frequency response. A chirped grid electrode balances semiconductor sheet resistance and metal line resistance components of the series resistance.