An optoelectronic module may include an optical receiver optically coupled with an optical fiber. The optical receiver may be configured to receive time synchronization signals from the optical fiber. The time synchronization signals may be frequency modulated, wavelength modulated, or amplitude modulated and may be received along with received data signals. A time synchronization signal detection module may be communicatively coupled to the optical receiver. The time synchronization signal detection module may be configured to receive the time synchronization signals that are transmitted through the optical fiber and detect frequency modulations, wavelength modulations, or amplitude modulations to recover the time synchronization signals.

An optical transmission system includes: a terminal station device that transmits a wavelength multiplexed optical signal resulting from multiplexing an optical signal and dummy light; and an optical add-drop multiplexer that receives respective wavelength multiplexed optical signals transmitted from a plurality of the terminal station devices and performs add-drop processing on the wavelength multiplexed optical signals. The dummy light has a wavelength arrangement in which adjacent wavelengths are arranged with equal spacing, and the wavelength arrangement of the dummy light differs between the terminal station devices.

A transmitter (TX) for a WDM optical link includes a light source (CS) generating a plurality of discrete lines (EL) with different frequencies (f), a plurality of modulators (FSM, RRM, MZM), each modulator (FSM, RRM, MZM) being configured to modulate one of the discrete lines (EL) according to a data stream (c.sub.1-c.sub.4), at least one optical amplifier (SOA) configured to simultaneously amplify multiple lines (EL), wherein only a subset of the generated lines (EL) is routed to the optical amplifier (SOA) resp. to each one of the optical amplifiers (SOA). A receiver (RX) for an optical link adapted to work together with the transmitter (TX) is also described. An optical link including the transmitter (TX) and/or the receiver (RX), and a method to operate said link are also described.

[Problem] To provide an optical device capable of suppressing an optical signal from being trimmed because of band narrowing due to optical filters.

[Solution] An optical device according to the present invention is provided with a plurality of optical filters each of which filters an optical signal in a predetermined band out of a plurality of optical signals with wavelengths different from one another. The plurality of optical filters are configured in such a way that portions of the pass bands (13_1, 13_2, 13_3) of respective optical filters that respectively pass optical signals (15_1, 15_2, 15_3) with wavelengths adjacent to each other overlap each other.

A system or a network may include an optoelectronic module that includes an optical transmitter optically coupled with an optical fiber, and a controller communicatively coupled to the optical transmitter. The controller may be configured to operate the optical transmitter to transmit data signals through the optical fiber. The optoelectronic module may be configured to transmit time synchronization signals through the optical fiber along with the data signals.

Disclosed is a multi-wavelength transmission apparatus including a wavelength divider to divide an optical signal by wavelength and output wavelength-divided optical signals to different positions, the optical signal being received from an optical circulator, a first cylindrical lens to diverge the wavelength-divided optical signals along an X axis and a Y axis and allow the wavelength-divided optical signals to be promoted in a Z-direction, a second cylindrical lens to diverge optical signals output from the first cylindrical lens along the X axis and the Y axis and allow the output optical signals to be promoted in the Z-direction, and a reflector to reflect optical signals output from the second cylindrical lens toward the second cylindrical lens, the first cylindrical lens being identical in shape to the second cylindrical lens and rotated by 90 in an Y-axial direction based on the second cylindrical lens.

Methods and systems for a free space CWDM MUX/DEMUX for integration with a grating coupler based silicon platform may include an optical assembly comprising a lens array and a plurality of thin film filter splitters having angled reflective surfaces. The optical assembly may be operable to receive an input optical signal comprising a plurality of optical signals at different wavelengths via an optical fiber, focus the input optical signal onto a first thin film filter splitter, reflect a first of the optical signals into the lens array and passing others to a second thin film filter splitter, and reflect a second optical signal into the lens array and passing others to a third of the plurality of thin film filter splitters.

A multiplexer/demultiplexer and a passive optical network system are provided. The multiplexer/demultiplexer includes N optical multiplexing/demultiplexing modules. The optical multiplexing/demultiplexing modules multiplex signals with different wavelengths from a plurality of ports to a same port, or demultiplex signals with different wavelengths from one port to different ports. The N optical multiplexing/demultiplexing modules correspond to the signals with different wavelengths. In the optical multiplexing/demultiplexing modules, a negative dispersion amount and an insertion loss of an M.sup.th optical multiplexing/demultiplexing module are less than those of an (M+1).sup.th optical multiplexing/demultiplexing module, where N is a positive integer, and M is a positive integer less than or equal to N. The multiplexer/demultiplexer and the passive optical network system increase an optical power budget between an optical transmitter and an optical transceiver.

Disclosed herein is wavelength-division multiplexer with an internal optical signal tuned by a mounted signal pitch router. In particular, disclosed is a wavelength-division multiplexing (WDM) optical assembly including an optical signal router, a WDM filter, and a signal pitch router. The WDM filter has a wavelength selective surface positioned proximate the second side of the optical signal router. The signal pitch router has a transmissive surface positioned proximate to a side of the optical signal router, and a second reflective surface opposite the transmissive surface. A depth of the signal pitch router establishes and tunes a pitch of a routing optical path within the optical signal router. This provides for easier, faster, more reliable, and more cost effective manufacturing and assembly of the WDM optical assembly.

A method, computer-readable storage device and apparatus for routing traffic in a reconfigurable optical add-drop multiplexer layer of a dense wavelength division multiplexing network are disclosed. For example, the method determines the reconfigurable optical add-drop multiplexer layer has asymmetric traffic, and routes the asymmetric traffic in the reconfigurable optical add-drop multiplexer layer over a plurality of asymmetrical optical connections, wherein the plurality of asymmetrical optical connections is provided with only uni-directional equipment in the reconfigurable optical add-drop multiplexer layer.