Microstructures of micro and/or nano holes on one or more surfaces enhance photodetector optical sensitivity. Arrangements such as a CMOS Image Sensor (CIS) as an imaging LIDAR using a high speed photodetector array wafer of Si, Ge, a Ge alloy on SI and/or Si on Ge on Si, and a wafer of CMOS Logic Processor (CLP) ib Si fi signal amplification, processing and/or transmission can be stacked for electrical interaction. The wafers can be fabricated separately and then stacked or can be regions of the same monolithic chip. The image can be a time-of-flight image. Bayer arrays can be enhanced with microstructure holes. Pixels can be photodiodes, avalanche photodiodes, single photon avalanche photodiodes and phototransistors on the same array and can be Ge or Si pixels. The array can be of high speed photodetectors with data rates of 56 Gigabits per second, Gbps, or more per photodetector.

A circuit for detecting an optical data signal includes a photonics substrate and first and second photodiodes formed in the photonics substrate. The first photodiode is configured to receive, via an input port formed in the photonics substrate, a first portion of the optical data signal and convert light power of the first portion of the optical data signal to generate a first current based on the optical data signal. The second photodiode is configured to output a second current without receiving any portion of the optical data signal. The second current corresponds to a dark current induced in the second photodiode. The circuit is configured to subtract the second current from the first current to generate an output signal corresponding to a power of the optical data signal without dark current induced in the first photodiode.

In some examples, a multi-wavelength power meter may include a first coupler to separate optical signals from an optical line terminal and an optical network terminal to ascertain a reduced percentage of total power related to the optical signals. A second coupler may receive the separated optical signals, combine the separated optical signals, and output the combined optical signals to an optical fiber. A filter may be communicatively connected to the optical fiber to isolate at least one specified wavelength or wavelength range of the combined optical signals. A photodiode may be communicatively connected to the filter for power measurement of the at least one specified wavelength or wavelength range.

A high-speed, wavelength-converting receiver that includes a housing; a high-speed, wavelength-converting layer attached to the housing and configured to absorb a first light having a first wavelength range and emit a second light having a second wavelength range, which is different from the first wavelength range; and a high-speed photodetector attached to the housing and having an active face configured to absorb the second light having the second wavelength range and generate an electrical signal. The active face of the photodetector is fully placed within the housing.

A test apparatus has at least one optical source, a high-speed photodetector, a microcontroller or processor, and electrical circuitry to power and drive the optical source, high-speed photodetector, and microcontroller or processor. The apparatus measures the frequency response and optical path length of a multimode optical fiber under test, utilizes a reference VCSEL spatial spectral launch condition and modal-chromatic dispersion interaction data to estimate the channels total modal-chromatic bandwidth of the fiber under test, and computes and presents the estimated maximum data rate the fiber under test can support.

The invention relates to a method for decoding (10) a modulated light signal (35) carrying a digital data set, the decoding method (10) comprising a step of searching (12, 13, 14, 15) for at least two frequencies of oscillation of a digital transcription of the light signal detected by a photodetector (23), each frequency of oscillation being representative of a logic value of the bits constituting the digital data carried by the light signal. Advantageously, a most significant bit is represented by a first frequency of oscillation and a least significant bit is represented by a second frequency of oscillation, the first frequency of oscillation being chosen so as to form, at the photodetector (23), a digital signal that is larger than that formed by the second frequency of oscillation by at least 4 elementary detection units of said photodetector (23).

The invention also relates to an optoelectronic system (20) that implements a decoding method (10) of this kind.

A multi-system optical communication switching module is disclosed. The multi-system optical communication switching module communicates with a communication system and controls a photoelectric converter through a plurality of optical transceiver signals. The multi-system optical communication switching module comprises a system storage unit and an optical communication control unit. The system storage unit includes system settings, the system storage unit selects one of the system settings according to the communication system and output the system storage data. The photoelectric signal processor generates a photoelectric conversion signal via receiving the control signal of the signal controller and the system storage data, and transmitting the photoelectric conversion signal to the photoelectric converter. When switching the system setting, the photoelectric conversion signal is generated to the photoelectric converter according to the system storage data, so that the setting can be adjusted to adapt to the communication system.

A receiving circuit and an optical receiver including the receiving circuit are disclosed. The receiving circuit includes first and second input terminals, a FET, first and second TIA circuits, and a control circuit. The first and second input terminals each receive a current signal. The FET has first and second current terminals respectively connected to the first and second input terminals, and a control terminal. The first and second TIA circuits respectively are connected to the first and second current terminals, and convert the current signals to first and second voltage signals. The control circuit generates a control signal for application to the FET control terminal in accordance with a difference between the first and second voltage signals. The optical receiver includes the receiving circuit and each of first and second photodetectors for respectively supplying first and second current signals to the first and second input terminals of the receiver.

A method for making a pair of photodiodes to detect low-power optical signal includes providing a waveguide including one or more branches in a silicon photonics substrate to deliver an input optical signal to the silicon photonics integrated circuit; forming a pair of nearly redundant photodiodes in silicon photonics platform in the silicon photonics substrate. coupling a first one of the pair of nearly redundant photodiodes optically to each of the one or more branches for receiving the input optical signal combined from all of the one or more branches; coupling a second one of the pair of nearly redundant photodiodes electrically in series to the first one of the pair of nearly redundant photodiodes; and drawing a current from the first one of the pair of nearly redundant photodiodes under a reversed bias voltage applied to the pair of nearly redundant photodiodes.

A free-space optical communication device includes an optical fiber bundle and one or more processors. The optical fiber bundle includes a central fiber connected to a first photodetector, and a plurality of surrounding fibers, each surrounding fiber connected to a corresponding second photodetector. The one or more processors are in communication with the first photodetector and each second photodetector. The one or more processors are also configured to receive a current or voltage generated at the first photodetector and each second photodetector and to determine a pointing accuracy of a beam received at the optical fiber bundle based on the current or voltage generated at the second photodetectors.