A system for communication is provided. The system includes an emitter transmitting a first code of a first wavelength. The system includes a filter or variable waveplate receiving the first code. The system includes a receiver sensor receiving the filtered first code. The system includes the emitter transmitting a second code of a second wavelength. The system includes the variable waveplate or other filter receiving the second signal. The system includes the receiver sensor receiving the filtered second code. The first and second codes may be used for communication, synchronizing the emitter, and other purposes.

A short-waveband active optical component based on a vertical emitting laser and a multi-mode optical fiber has an emitting end and a receiving end. In the emitting end, multiple VCSELs generate multiple optical signals of different wavelengths, and multiple photodiodes in the receiving end receive the optical signals emitted by the VCSELs. Both ends use a focusing lens array to collimate and focus the optical signals A Z-block-shaped prism performs a light combining function at the emitting end, while another Z-block-shaped prism performs a light splitting function at the receiving end. Both ends use a focusing lens for collimating and focusing the optical signals at ends of a multi-mode optical fiber, which is used for transmitting the optical signals generated by the VCSELs. The short-waveband active optical component has a small size and a high transmission rate.

In order to improve free space optical communications, an optical communication terminal includes a laser source, a photo detecting apparatus and an optical input/output assembly. These components are controlled by a control logic. In order to have the optical communication terminal to be self-compatible, the optical input/output assembly selectively routes the outgoing beam and incoming beam depending on their respective beam polarization. To this end, the optical input/output assembly may include a polarizing beam splitter together with a quarter-wave plate.

A LIDAR system that identifies, from a channel output, a false positive return and/or suppressing a corresponding false positive detection caused, in some cases, a strong reflection by a highly reflective surface that caused light to leak from a first channel to a second channel. The LIDAR system described herein may identify, as a false return, a return detected in the second channel that has an intensity that is much less than a return in the first channel and indicates a distance that is the same or very close to a distance indicated the return in the first channel. Based at least in part on identifying a return as a false return, the LIDAR system may suppress a false detection associated with the false return by modifying a detection threshold.

A system comprises a writer to form a plurality of color mits on a base material, wherein at least one of the color mits may represent computer-readable instructions comprising data other than pixel-image data. The plurality of color mits may include a first color mit and a second color mit, wherein the first color mit represents information data, and the second color mit represents that the first color mit contains a particular type of information data. The system also may include a reader to read colors of the plurality of color mits on the base material. The system may comprise a device to map at least one of the color mits to computer-readable instructions. The system may further comprise a processor configured to transmit signals using a colored light.

A laser device for optical communication comprises a first laser unit connected to a first optical fiber for supplying a transmission laser beam thereto. wherein the laser device is configured for providing a reference laser beam in addition to the transmission laser beam. For providing the reference laser beam the laser device further includes a second laser unit connected to a second optical fiber for supplying the reference laser beam to the second optical fiber. The first laser unit is configured for providing the transmission laser beam as a linear polarized beam that is polarized in a first polarization direction, and the second laser unit is configured for providing the reference laser beam as a linear polarized beam that is polarized in a second polarization direction. The first optical fiber and the second optical fiber are formed of polarization maintaining optical fibers, and the laser device further includes a polarization combiner connected to a third polarization maintaining optical fiber for conveying the transmission laser beam and the reference laser beam to an optical output of the laser device.

An optical filter includes a first ring resonator a second ring resonator having different perimeters, and a waveguide optically coupled to the first ring resonator and transmit light to the first ring resonator. Light incident on the waveguide is transmitted to the second ring resonator through the first ring resonator. A free spectral range of a transmission spectrum of the first ring resonator and a free spectral range of a transmission spectrum of the second ring resonator are staggered to each other, and are set so that a transmission spectrum of a double ring corresponding to a synthetic spectrum of the transmission spectrum of the first ring resonator and the transmission spectrum of the second ring resonator has a highest first peak at an arbitrary wavelength.

According to examples, a channel checker optical time-domain reflectometer (OTDR) may include a laser source to emit a laser beam, An optical switch may be optically connected to the laser source to receive the laser beam and to selectively transmit the laser beam to a circulator that is optically connected to a device under test (DUT). A first coupler may be optically connected to a first photodiode and to the circulator, A second coupler may be optically connected to the first coupler, the optical switch, and a second photodiode.

This application discloses a signal generating method, apparatus, and system. One example method includes: performing cyclic electro-optic modulation on a first signal to generate a first optical frequency comb signal, where the first signal is a signal output by a laser source, the first optical frequency comb signal includes a target spectral component, and a frequency of the target spectral component is equal to a sum of or a difference between a frequency of the first signal and a frequency of a target signal; performing first filtering processing on the first optical frequency comb signal to generate the target spectral component; and generating the target signal based on a heterodyne beat frequency of the first signal and the target spectral component.

An apparatus for generating a time-delayed product of two independent signals includes a fixed-wavelength laser. A first optical modulator is optically coupled to the fixed-wavelength laser and configured to modulate a fixed wavelength optical carrier with a first input signal of a set of input signals. The apparatus also includes a tunable laser. A second optical modulator is optically coupled to the tunable laser and configured to modulate a tunable optical carrier with a second input signal of the set of input signals. The apparatus also includes a dispersive element coupled to the second optical modulator, a first optical detector coupled to the dispersive element, a third optical modulator optically coupled to the first optical detector and the first optical modulator, an optical 90-degree hybrid element optically coupled to the third optical modulator, and a plurality of optical detectors optically coupled to the optical 90-degree hybrid element.