National Central University

Industrial Technology Research Institute

National Taiwan University

Jin-Wei Shi

Feng-Ming Kuo

Chee-Wee Liu

Jinn-Kong Sheu

Nan-Wei Chen

Hsuan-Ju Tsai

Jen-Inn Chyi

Yu-Min Hsu

Chun-Kai Wang

Zing-Way Pei

Mao-Jen Wu

Fon Yuan

Ying-Jay Yang

Yen-Hsiang Wu

Kai-Lun Chi

Cheng-Hiong Chen

Tzi-hong Chiueh

Chen-An Hsieh

Hsiao-Feng Teng

Yi-Shan Lee

Fong-Ming Kuo

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.

Frequency modulation continuous wave lidar device

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.

Array of surface-emitting lasers with high-brightness unipolar output

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.

Single-photon detector having multiple avalanche layers

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.

Photodiode of avalanche breakdown having mixed composite charge layer

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 AlOsacrificial 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.

Method of substrate lift-off for high-efficiency group III-V solar cell for reuse

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 (GaAsSb) and indium gallium arsenide (InGaAs), the incorporation of the type-II P-GaAsSb/i-InGaAs 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 GaAsSblayer 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 &#x2212;3 decibel-milliwatts are demonstrated at an operating frequency of 0.32 THz under an optical signal with a sinusoidal wave and a &#x2dc;63% modulation depth for PD excitation.

Type-II hybrid absorber photodetector

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.

Avalanche photodiode having electric-field confinement by mesas

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.

Vertical-cavity surface-emitting laser device having relief structure

A homojunction type high-speed photodiode has an active area of greater than at least 50 microns (&#x3bc;m) or preferably greater than 60 microns (&#x3bc;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.

Homojunction type high-speed photodiode

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.

Photonic generator of ultra-wide band millimeter wave

The present disclosure provides a high-speed laser power converter (LPC). The LPC is able to be cascaded. The LPC has a high-speed photodiode (PD) performance even operated under a forward bias operational voltage. Thus, the present disclosure can generate power (instead of consume power) during high-speed data transmission in an optical interconnect (OI) system using 850 nano-meters (nm) wavelength vertical cavity surface-emitting laser (VCSEL).

Laser power converter for data detection and optical-to-electrical power generation

An optoelectronic switch using millimeter wavelength (MMW) is provided. An r voltage pulse is applied to a device under test (DUT) for switching the photo-generated MMW power The DUT is operated under reverse bias. An optical light source with modulated MMW envelop is injected on to DUT for MMW power generation. Thus, based on change of the reverse bias, speed is violently changed and the MMW optoelectronic switch is thus obtained.

Optoelectronic switch transmitter using millimeter wavelength

The present disclosure uses at least two cascaded photodetectors. Device area is increased to provide a bigger current than a single photodetector under the same bandwidth. Hence, bandwidth efficiency (BRP) and saturation current-bandwidth product (SCBP) are improved for a high speed, a high responsivity and a high bandwidth with simple structure and low cost.

Multi-cascaded photodiode

An optoelectronic device is provided. A light source emitter and a light source receiver are integrated in the device. The light source emitter is a Zn-diffused vertical cavity surface-emitting laser (VCSEL). The light source receiver is a uni-traveling-carrier photodiode (UTC-PD). With the VCSEL, a 10 Gb/s eye is opened under a small voltage and a small signal amplitude. With the UTC-PD, the 10 Gb/s eye is passed even under zero-bias. Thus, the optoelectronic device has a high speed and power consumption is saved.

Optoelectronic device having light source emitter and receiver integrated

The present invention changes layer polarities of an epitaxy structure of an avalanche photodiode into n-i-n-i-p. A transport layer is deposed above an absorption layer to prevent absorbing photon and producing electrons and holes. A major part of electric field is concentrated on a multiplication layer for producing avalanche and a minor part of the electric field is left on the absorption layer for transferring carrier without avalanche. Thus, bandwidth limit from a conflict between RC bandwidth and carrier transferring time is relieved. Meanwhile, active area is enlarged and alignment error is improved without sacrificing component velocity too much.

Growing community of inventors

Taipei, Taiwan

Jin-Wei Shi