An optical receiver is described. Using silicon-photonic components that support a single polarization, the output of an optical receiver is independent of the polarization of an optical signal. In particular, using a polarization-diversity technique, the two orthogonal polarizations in a single-mode optical fiber are split in two and processed independently. For example, the two optical signals may be provided by a polarization-splitting grating coupler. Subsequently, a redistribution element provides mixtures of the two optical signals. Next, a wavelength channel in the two mixed optical signals is selected using a wavelength-selective filter (for example, using ring-resonator drop filters or an echelle grating) and converted into an electrical signal at an optical detector (such as a photodetector) to achieve polarization-independent operation.

A wavelength converter that converts signal light and pump light into a light containing a new wavelength component using a nonlinear optical fiber, has a PBS for splitting incident light into a first polarized wave and a second polarized wave, a first polarization controller provided between the PBS and a first end of the nonlinear optical fiber, and a second polarization controller provided between the PBS and a second end of the nonlinear optical fiber, wherein in an optical loop connecting the PBS, the first polarization controller, the nonlinear optical fiber and the second polarization controller, the first polarized wave and a first component of the pump light travel through the nonlinear optical fiber in a first direction, and the second polarized wave and a second component of the pump light travel through the nonlinear optical fiber in a second direction opposite to the first direction.

Consistent with an aspect of the present disclosure, electrical signals or digital subcarriers are generated in a DSP based on independent input data streams. Drive signals are generated based on the digital subcarriers, and such drive signals are applied to an optical modulator, including, for example, a Mach-Zehnder modulator. The optical modulator modulates light output from a laser based on the drive signals to supply optical subcarriers corresponding to the digital subcarriers. These optical subcarriers may be received by optical receivers provided at different locations in an optical communications network, where the optical subcarrier may be processed, and the input data stream associated with such optical subcarrier is output. Accordingly, instead of providing multiple lasers and modulators, for example, data is carried by individual subcarriers output from an optical source including one laser and modulator. Thus, a cost associated with the network may be reduced. Moreover, each of the subcarriers may be detected by a corresponding one of a plurality of receivers, each of which being provided in a different location in the optical communication network. Thus, receivers need not be co-located, such that the network has improved flexibility.

An optical transmission device includes a first wavelength multiplexer, a second wavelength multiplexer, a wavelength converter and a third wavelength multiplexer. The first wavelength multiplexer multiplexes optical signals in a first wavelength band to generate first wavelength multiplexed light. The second wavelength multiplexer multiplexes optical signals in the first wavelength band to generate second wavelength multiplexed light in a first polarization. The wavelength converter converts a wavelength of the second wavelength multiplexed light from the first wavelength band into a second wavelength band by a cross phase modulation among the second wavelength multiplexed light, first pump light in a second polarization and second pump light in the second polarization. The second polarization is orthogonal to the first polarization. The third wavelength multiplexer multiplexes the second wavelength multiplexed light whose wavelength has been converted by the wavelength converter and the first wavelength multiplexed light.

A hyperspectral radiometer may comprise one or more antennas, a electro-optical modulator modulating the received RF signal onto an optical carrier to generate a modulated signal having at least one sideband; a filter filtering the modulated signal to pass the sideband to a photodetector; and a photodetector producing an electrical signal from which information of the RF signal can be extracted. In some examples, the optical sideband may be spatially dispersed to provide a plurality of spatially separate optical components to the photodetector, where the spatially separate optical components having different frequencies and correspond to different frequencies of the received RF signal. In some examples, the passed sideband may be mixed with an optical beam having a frequency offset from the optical carrier to form a combined beam having at least one optical signal component having a beat frequency from which information of the RF signal can be extracted.

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.

Embodiments describe optical imagers that include one or more micro-optic components. Some imagers can be passive imagers that include a light detection system for receiving ambient light from a field. Some imagers can be active imagers that include a light emission system in addition to the light detection system. The light emission system can be configured to emit light into the field such that emitted light is reflected off surfaces of an object in the field and received by the light detection system. In some embodiments, the light detection system and/or the light emission system includes micro-optic components for improving operational performance.

Embodiments of the disclosure pertain to an optical transmitter and/or receiver comprising an electrical signal generator configured to generate an electrical signal that is unshielded or unshieldable at a predetermined frequency, a filter downstream from the electrical signal generator configured to reduce an amplitude of electromagnetic interference (EMI) at the predetermined frequency below a predetermined maximum value, an interface through which the EMI can pass in the absence of the filter, and an optical component configured to receive the electrical signal or provide an input signal to the electrical signal generator. A method of reducing EMI in an optical transmitter and/or receiver using the electrical signal generator, the filter and the optical component is also disclosed.

Consistent with an aspect of the present disclosure, electrical signals or digital subcarriers are generated in a DSP based on independent input data streams. Drive signals are generated based on the digital subcarriers, and such drive signals are applied to an optical modulator, including, for example, a Mach-Zehnder modulator. The optical modulator modulates light output from a laser based on the drive signals to supply optical subcarriers corresponding to the digital subcarriers. These optical subcarriers may be received by optical receivers provided at different locations in an optical communications network, where the optical subcarrier may be processed, and the input data stream associated with such optical subcarrier is output. Accordingly, instead of providing multiple lasers and modulators, for example, data is carried by individual subcarriers output from an optical source including one laser and modulator. Thus, a cost associated with the network may be reduced. Moreover, each of the subcarriers may be detected by a corresponding one of a plurality of receivers, each of which being provided in a different location in the optical communication network. Thus, receivers need not be co-located, such that the network has improved flexibility.

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.