A first optical transmission device includes a plurality of first lasers having a different corresponding wavelength, a first optical path component, a first modulator, and a first processor portion. The plurality of first lasers is connected to a plurality of optical input ports of the first optical path component respectively. The first optical path component is configured to perform multiplexing on continuous light of different wavelengths emitted by the plurality of first lasers, and perform power splitting of multiplexed continuous light thereby obtaining two paths of continuous light, send a first path of continuous light to the first modulator, and send a second path of continuous light to a second optical transmission device at a peer end. The first processor portion is configured to send a first analog signal to the first modulator. The first modulator is configured to at least modulate the first analog signal onto the first path.

An optical receiver, used in wavelength-division multiplexing, has multiple photodetectors per channel. The optical receiver comprises a demultiplexer to separate incoming light into different output waveguides, one output waveguide for each channel. A splitter is used in each output waveguide to split each output waveguide into two or more branches. A separate photodetector is coupled with each branch so that two or more photodetectors are used to measure each channel.

In some embodiments, an apparatus includes a first optical transceiver. The first optical transceiver includes a set of optical transmitters, an optical multiplexer operatively coupled to the set of optical transmitters, and a variable optical attenuator operatively coupled to the optical multiplexer. The variable optical attenuator is configured to receive a control signal from a controller of the first optical transceiver and modulate a signal representing control information with an output from the optical multiplexer. The control information is associated with the control signal and for a second optical transceiver operatively coupled to the first optical transceiver.

A method for generating frequency converted laser radiation is disclosed. The disclosure provides a method enabling generation of a frequency converted wavelength division multiplexed light source that is easy to implement at low cost. Adjustment of the center frequency and the mode spacing in a frequency converted wavelength division multiplexed light source is also disclosed. A related method of use discloses generating pump laser radiation through combination of multiple pump sources in a wavelength division multiplexed arrangement; passing the pump laser radiation through the non-linear medium of a singly resonant, single-frequency optical parametric oscillator, wherein the pump laser radiation is continuous wave or pulsed, wherein the pulse duration in the latter case is longer than the time the optical parametric oscillation requires to reach its steady state; and coupling out the non-resonant idler or signal laser radiation from the optical parametric oscillator as usable frequency converted laser radiation. Moreover, the invention relates to a laser device for carrying out the method of the invention.

An optical wavelength-division multiplexing (WDM) device utilizing a mechanism of folded optical-path includes multiple collimators, optical filters, prism, and glass plate. The collimators are capable of collimating optical lights for facilitating free-space optical communication. The optical filters optically coupled with the collimators provide filtering functions to separate optical wavelengths in accordance with the configurations or characteristics of optical filters. The prism having an interface surface and two side surfaces is configured to direct or redirect optical beams based on the angle of incidence (AOI) of each optical beam received. The glass plate, in one embodiment, physically configured to be situated in parallel with the collimators is capable of providing free-space optical paths for facilitating separation of wavelengths.

Aspects of the subject disclosure may include, for example, a device that encodes digital signals representing image data captured by a video camera and provided according to a 4K ultra-high definition (4K-UHD) standard. The digital signals are transmitted as serial digital interface (SDI) streams to a wavelength-division multiplexing (WDM) unit; the WDM unit performs electrical-to-optical conversion of the SDI streams and outputs a multiplexed signal to a single fiber-optic cable. The video camera, encoding unit, and WDM unit form a combined module within a housing; the device connects to a proximal end of a single fiber-optic cable, and a distal end of the single fiber-optic cable is configurable for connection to a demultiplexer of a 4K-UHD video presentation device. The multiplexed signal is transmitted on the single fiber-optic cable unidirectionally from the proximal end to the distal end. Other embodiments are disclosed.

An optical transmission apparatus includes a wavelength converter that wavelength-converts input signal light using a nonlinear optical medium to output the converted signal light, a memory that holds first information relating to a wavelength conversion characteristic of the wavelength converter, a communication interface that receives second information relating to a second wavelength conversion characteristic of an adjacent optical transmission apparatus, and a control circuit that determines, using the first information and the second information when the second information is received, an excitation light frequency at which a gain deviation of main signal light subjected to a wavelength conversion is minimized to set the determined excitation light frequency in the wavelength converter.

In one embodiment, a first group of splitters receives a group of signals from a group of transmitters. Each splitter in the first group of splitters splits a signal into a plurality of signals that are sent to a plurality of multiplexers. A multiplexer in the plurality of multiplexers receives one of the plurality of signals from each splitter in the group of splitters and multiplexes the received one of the plurality of signals into a multiplexed signal. The multiplexer sends the multiplexed signal through a single connection in which upstream signals are sent to a group of nodes and downstream signals are received from the group of nodes. A de-multiplexer de-multiplexes the multiplexed signal into the group of signals and sends the group of signals to the group of nodes via a second group of splitters that are connected to the group of nodes.

An optical receiver includes: an optical demultiplexer to demultiplex an optical signal in which a plurality of wavelengths is multiplexed and divide the optical signal into optical signals corresponding to the plurality of wavelengths, respectively; a reflector to change a progress direction of the divided optical signals; an optical coupling lens including, in an array form, light transmission lenses through which the divided optical signals are transmitted, respectively; a plurality of photodetectors to mount on a photodiode (PD) substrate provided on the optical coupling lens, receive the divided optical signals that are transmitted through the light transmission lenses of the optical coupling lens, respectively, and convert the received optical signals to electrical signals; and a plurality of trans impedance amplifiers provided at desired intervals to electrically connect to the plurality of photodetectors through wire bonding and amplify the received plurality of electrical signals to be a desired magnitude.

A method of beamforming by which a signal can be received into an array of channels, each of which is split into a real-part sub-channel and an imaginary part sub-channel. In each sub-channel, optical waves are used to carry the signal via waveguides. Each channel includes a real-part sub-channel where an optical wave is scaled by the real part of a complex number, and an imaginary part sub-channel, where a complementary optical wave is scaled by the complex part of the same complex number. When the complementary optical waves are received at the channel's output, they can be shifted by the phase of the complex number having defined their scaling. By processing a signal with a system operative to perform such method, the application of a different phase to each channel can result in a beamforming of the signal.