Abstract: A four-dimensional (4D) light-detection-and-ranging sensor using frequency modulated continuous wave is provided with an ultra-high velocity resolution. At a transmitting terminal, the hybrid waveform of a driving laser is used to minimize the phase noise generated by a distributed-feedback laser during wavelength scanning. The hybrid waveform is obtained by combining direct-current signal (not modulated) and alternating-current (AC) signal. The AC signal is a predistorted triangle or AC waveform for extracting location. The continuous wave (CW) extracts velocity. At a receiving terminal, a radar radio-frequency receiver is combined with an avalanche photodiode (APD) with multiple layers accumulated in series to obtain excellent responsivity and saturated current. The mixed waveform coordinated with the APD prevents Doppler shift frequency from being contaminated by low-frequency flicker noise.

Abstract: An avalanche photodiode (APD) with cascaded multiplication layers (M-layer) is provided. The APD is applied to high speed and wide dynamic range applications. It has an epitaxial-layers structure. The structure is formed by inserting at least one charge layer into a single M-layer. The single M-layer is thus sliced into at least two layers, a first and a second M-layers, of different thicknesses. Thus, edge breakdown is suppressed and the increase of dark current caused by M-layer reduction is relieved for high speed performance.

Abstract: A multi-electrode device is provided. The device improves electrical-to-optical (E-O) frequency response in vertical cavity surface emitting laser (VCSEL) array. An electrode is used in a near quasi-single-mode (QSM) VCSEL array having zinc diffusion apertures for enhancing high-speed data transmission. By forming a distance less than 20 microns between the centers of every two neighboring apertures in the VCSEL array being compact 2×2-coupled, high-speed data transmission is significantly enhanced. The present invention exhibits good electro-optical frequency response suppression and good 3-decibel E-O bandwidth. Concerning the maximum QSM optical output power and the Gaussian-like optical far-field with a narrow diverging angle, significant improvement in dynamic performance do not sacrifice static performance.

Abstract: A cascaded avalanche photodiode (APD) is provided with high responsivity and high saturation current. Single multiplication layer (M-layer) is inserted with multiple field control layers to be cut into several M-layers in different regions. Thus, with the breakdown voltage decreased, the critical field lowered, the saturation power enhanced, and the gain increased, avalanche breakdown effect is achieved.

Abstract: A lidar device, comprising a laser generator and a lidar unit, is provided and operated with frequency modulation continuous wave. The laser generator comprises an amplifier unit; and a reflector unit connected with at least one end of the amplifier unit. The amplifier unit comprises at least one first luminous gain area and at least one second luminous gain area. The first luminous gain area is operated in a saturated region with a first current source applied. The second luminous gain area is operated in a linear region with a second current source applied. Thus, a laser is generated and outputted to the lidar unit. The laser generator is operated with the luminous gain areas of the amplifier unit pushed into the saturated region to suppress intensity modulation and fix power. Even if current changes, frequency drifts only with continuity and adjustability achieved and no mode hop happened.

Abstract: An array of surface-emitting lasers is provided. The array outputs high brightness in a unipolar way. The array comprises a stress-adjustment unit and a plurality of epitaxial device units. The stress-adjustment unit is used to adjust stress. The stress from a substrate is used to select a laser mode for an aperture unit. The selection of the laser mode is enhanced for the aperture unit without sacrificing driving current. Low current operation is achieved in a single mode for effectively reducing volume and further minimizing the size of the whole array to achieve high-quality laser output. An object can be scanned by the outputted laser to obtain a clear image with a high resolution. Hence, the present invention is applicable for face recognition with high recognition and high security.

Abstract: An array of surface-emitting lasers is provided. The array outputs high brightness in a unipolar way. The array comprises a stress-adjustment unit and a plurality of epitaxial device units. The stress-adjustment unit is used to adjust stress. The stress from a substrate is used to select a laser mode for an aperture unit. The selection of the laser mode is enhanced for the aperture unit without sacrificing driving current. Low current operation is achieved in a single mode for effectively reducing volume and further minimizing the size of the whole array to achieve high-quality laser output. An object can be scanned by the outputted laser to obtain a clear image with a high resolution. Hence, the present invention is applicable for face recognition with high recognition and high security.

Abstract: A single-photon detector is provided. The detector has multiple avalanche layers. It has an avalanche photodiode (APD) structure using single photon. The APD is made of indium aluminum arsenide (InAlAs). At least two avalanche layers are designed. When the layer for avalanche is numbered only one and the gain is very big, the speed will be deteriorated very quickly. With the design of two avalanche layers in the present invention for the very big gain, the speed deterioration can be suppressed. After measuring, the present invention shows a faster speed as compared to prior arts. It proves that, by using more than two avalanche layers, the present invention effectively improves the feature of single-photon detector. Hence, the present invention is especially suitable for single-photon detection.

Abstract: An avalanche photodiode (APD) is provided with a mixed composite charge layer. A novel structure of InAlAs is designed with the mixed layer. A single P-type field control layer is divided into three layers of different materials with each two forming a heterojunction structure. By controlling the relative concentration distributions and thicknesses of the first, second, and third P-type field control layers along with a mesa shape formed through chemical selective etching, a part of the second P-type field control layer is exposed to the air with a part of the first one etched out at the same time through this single structure having the mesa shape. Thus, the field of a multiplication layer is further confined at center to concentrate electric-field so that fringe field is low but not collapsed. Hence, the overall speed is increased, the intensity high, and sensitivity good while response is fast and efficiency high.

Abstract: A method of is provided as a process of substrate lift-off. The present invention is mainly used for a group III-V solar cell, which has the highest power generation efficiency. An original sacrificial layer is changed into an AlAs oxide layer, which is transformed into an AlOx sacrificial layer after wet oxidation. The sacrificial layer is then soaked in an oxide-relief solution for etching. Thus, the lift-off process of a GaAs substrate can be harmlessly processed to the complex group III-V solar cell. The GaAs substrate can be recycled to be effectively further reused in photovoltaic devices with reduced cost.

Abstract: A method of is provided as a process of substrate lift-off. The present invention is mainly used for a group III-V solar cell, which has the highest power generation efficiency. An original sacrificial layer is changed into an AlAs oxide layer, which is transformed into an AlOx sacrificial layer after wet oxidation. The sacrificial layer is then soaked in an oxide-relief solution for etching. Thus, the lift-off process of a GaAs substrate can be harmlessly processed to the complex group III-V solar cell. The GaAs substrate can be recycled to be effectively further reused in photovoltaic devices with reduced cost.

Abstract: A photodetector is provided. The photodetector is an avalanche photodiode of indium aluminum arsenide (InAlAs). An epitaxial-layers structure with n-side down is used. The strongest electric field of a multiplication layer (M-layer) is coated in inner bottom layers to avoid surface breakdown. An intrinsic layer is thickened; only one absorption layer is used; and a DBR layer is added below an n-type ohmic contact layer. A graded bandgap layer is etched to form a single mesa shape. Through the single mesa shape, all layers are far below breakdown except the M-layer has a particularly high electric field for restraining the electric field. Thus, the present invention changes holes into electrons through p-type-doping the absorption layer; because electrons run fast, carriers is made run fast; and junction capacitance is reduced with surface area increased by depletion layer thickened. Consequently, fast response speed is obtained while sensitivity is effectively improved.

Abstract: A type-II hybrid absorber photodetector (PD) is provided with ultrafast speed and high-power performance at terahertz (THz) regime. Through narrowed bandgap and enhanced absorption process at a type-II interface between absorption layers of gallium arsenic antimonide (GaAs0.5Sb0.5) and indium gallium arsenide (In0.53Ga0.47As), the incorporation of the type-II P+-GaAs0.5Sb0.5/i-In0.53Ga0.47As hybrid absorber in an indium phosphide (InP) UTC-PD obtains improvement in responsivity. Current blocking effect is minimized owing to the high-excess energy of photo-generated electrons injected from the GaAs0.5Sb0.5 layer to an InP-based collector layer. The flip-chip bonding packaged device shows a moderate responsivity along with a record wide optical-to-electrical bandwidth at 0.33 THz, among all the reported for long-wavelength ultrafast PDs. A saturation current exceeding 13 mA and a continuous-wave output power of ?3 decibel-milliwatts are demonstrated at an operating frequency of 0.

Abstract: A novel photodetecting device having field confined by mesas is provided. The device is an avalanche photodiode (APD) of indium aluminum arsenide (InAlAs). The device has epitaxial layers with a multiplication layer at bottom as a cathode. Hence, the strongest electric field is confined inside the bottom of the device to avoid surface breakdown. Double mesa is used to confine the electric field of the multiplication layer. Furthermore, a composite multiplication layer with supper thin thickness and wide bandgap is used to reduce the tunneling dark current. Hence, the thickness of equivalent multiplication layer can be reduced to enhance sensitivity.

Abstract: A visible-light light emitting diode having a center wavelength of 400 to 560 nm formed on a patterned sapphire substrate and with a four-layer quantum well as an active layer. The patterned sapphire substrate can include a plurality of recesses having openings and a plurality of convex portions on one surface thereof, the recesses being integrally formed between the neighboring convex portions or a plurality of convex portions on one surface thereof, a recess being defined between two of the neighboring convex portions and wherein the convex portions on the surface are made of dielectric material. A lens layer is disposed on an upper P-type doped region.

Abstract: A new vertical-cavity surface-emitting laser (VCESL) is provided. With an undercut structure and a diffusion structure, the VCESL obtains a controllable number of optical modes for a distributed Bragg reflector (DBR). Thus, an electrical-to-optical bandwidth and a bit-rate transmission distance in OM4 fiber reach their biggest values. Besides, a biggest D-coefficient (˜13.5 GHz/mA1/2), a smallest energy-data rate under 34 Gbit/s (EDR:140 fJ/bit) and a smallest energy-data distance rate under 25 Gbit/s with 0.8 km of OM4 fiber (EDDR:175.5 fJ/bit·km) are obtained.

Abstract: The present disclosure is a vertical-cavity surface-emitting laser (VCSEL) device. A relief structure is formed above or below a light emitting region by partially removing an aluminum composition layer of VCESL through an etching process. Thus, profound static performances are obtained, including low power consumption, biggest operational speed, and high ratio of data transmission to power consumption as 2.9 and 9.2 Gbps/mW under 34 and 12.5 Gbps, respectively.

Abstract: A homojunction type high-speed photodiode has an active area of greater than at least 50 microns (?m) or preferably greater than 60 microns (?m) in diameter, which has an p-i-n junction epitaxial layer formed on a semiconductor substrate and includes a first ohmic contact layer, an absorption layer, a collector layer and a second ohmic contact layer. No more absorbance occurs in the collector layer of InGaAs, by means of completely absorbing the photon energy in advance by the absorption layer in which the absorption layer has powerful optical absorption constant. Not only can the prior art problems be solved, such as surface absorbance, but also improved electron transport can be achieved by using InGaAs as the constructing material, compared to other materials. The resistance capacitance (RC) for the entire structure can be significantly reduced, and the limitations to the bandwidth resulted from the carrier transport time can be improved.

Abstract: A photonic generator is provided. The photonic generator uses ultra-wide band millimeter wave (MMW) for generating a high-power ultra-broad band white noise. Thus, the present disclosure can be used for failure detection of instantaneous all-band device, noise detection of instantaneous all-band amplifier and mixer, wide-band cipher transmission, pseudo-random bit generation, ADC dithering of analog-digital converter, saturation power test of wide-band optical communicator, system noise detection of MMW receiver, and gain and phase detection of MMW interferometer.

Abstract: A photonic millimeter-wave generator capable of combining wired and wireless communication facilities to further elongate the transmission distance comprises a laser generator for generating a first optical signal; an optical frequency comb generator coupled with the laser generator; and a pulse shaper coupled with the optical frequency comb generator. The optical frequency comb generator receives the first optical signal generated by the laser generator and outputs a second optical signal. The second optical signal contains multiple frequency components and is sent to the pulse shaper. The pulse shaper adjusts the amplitude and phase of the second optical signal and then outputs the signal as a third optical signal.