Optical network systems and components are disclosed, including a transmitter comprising a digital signal processor that receives data; circuitry that generate a plurality of electrical signals based on the data; a plurality of filters, each of which receiving a corresponding one of the plurality of electrical signals, a plurality of roll-off factors being associated with a respective one of the plurality of filters; a plurality of DACs that receive outputs from the digital signal processor, the outputs being indicative of outputs from the plurality of filters; a laser that supplies light; and a modulator that receives the light and outputs from the DACs, and supplies a plurality of optical subcarriers based on the outputs, such that one of the optical subcarriers has a frequency bandwidth that is wider than remaining ones of the optical subcarriers, said one of the optical subcarriers carrying information for clock recovery.

An optical transmission apparatus includes an input unit, a demultiplexing unit, a measurement unit, and a switching unit. The input unit inputs a first multiplexed signal and a second multiplexed signal each obtained by multiplexing a plurality of optical signals having different wavelengths. The demultiplexing unit demultiplexes the first multiplexed signal and the second multiplexed signal by wavelength. The measurement unit measures qualities of a plurality of optical signals obtained by demultiplexing the first multiplexed signal and qualities of a plurality of optical signals obtained by demultiplexing the second multiplexed signal. The switching unit performs switching between the first multiplexed signal and the second multiplexed signal to be output to a subsequent stage based on a result of measurement by the measurement unit.

An optical transmitter, including a wavelength selector and a plurality of modulator groups, is proposed. Each modulator group includes a plurality of modulators, and operating wavelengths of any two modulators in a same modulator group are different. The wavelength selector is configured to: obtain a first beam from a multi-wavelength light source, and generate a second beam based on the first beam, where the second beam includes some of the plurality of wavelengths. A first modulator in a first modulator group is configured to modulate first to-be-sent data onto a first wavelength in the second beam.

A transmission apparatus executes a reception processing that receives a first alarm detected in a first transmission apparatus different from the own apparatus from among a plurality of transmission apparatus from a second transmission apparatus different from the own apparatus from among the plurality of transmission apparatus, executes a detection processing that detects a second alarm of the own apparatus, executes a mask processing that masks alarms including the first alarm received by the reception processing and the second alarm detected by the detection processing, and executes a sending processing that sends an alarm that is not masked by the mask processing from among the alarms to a third transmission apparatus different from the own apparatus and the second transmission apparatus from among the plurality of transmission apparatus or sending the alarm to a given apparatus different from any of the plurality of transmission apparatus.

An optical transmission apparatus includes a first transmitter configured to transmit a first optical signal in a first wavelength band and a second optical signal in a second wavelength band located next to the first wavelength band; a second transmitter configured to transmit a third optical signal in a third wavelength band located next to the second wavelength band and a fourth optical signal in a fourth wavelength band located next to the third wavelength band; and a processor coupled to the first transmitter and the second transmitter and configured to select the third wavelength band among the first wavelength band, the second wavelength band, the third wavelength band and the fourth wavelength band, and control the first wavelength band, the second wavelength band, and the fourth wavelength band based on the third wavelength band.

An optical reception device includes: an optical demultiplexer that has an input port and output ports, and configured to demultiplex a wavelength-multiplexed signal light input from the input port into a signal light for each wavelength and output the signal light from each of the output ports; a multi-wavelength light output circuit configured to output a wavelength light for each wavelength included in the wavelength-multiplexed signal light to the input port of the optical demultiplexer; and a processor configured to control the optical demultiplexer and the multi-wavelength light output circuit, wherein the optical demultiplexer includes symmetric Mach-Zehnder interferometers that each have a pair of arms of different lengths, and adjustors respectively that adjust optical phases in the asymmetric Mach-Zehnder interferometers, the asymmetric Mach-Zehnder interferometers are connected to each other in a tree-like shape so as to connect the input port and the output ports.

Systems and methods of sharing optical spectrum between a plurality of users of a submarine optical system includes receiving one or more optical signals from the plurality of users of the submarine optical system, wherein each of the plurality of users are assigned a slice of optical spectrum on the submarine optical system; monitoring each of the one or more optical signals to determine compliance with one or more constraints; and adding the one or more optical signals to the submarine optical system if compliant with the one or more constraints.

An injection locked transmitter for an optical communication network includes a primary seed laser source input substantially confined to a single longitudinal mode, an input data stream, and a laser injected modulator including at least one secondary laser having a resonator frequency that is injection locked to a frequency of the single longitudinal mode of the primary seed laser source. The laser injected modulator is configured to receive the primary seed laser source input and the input data stream, and output a laser modulated data stream.

A multi-channel optical transmitter or transceiver includes transmitter optical subassembly (TOSA) modules optically coupled to and directly aligned with mux input ports of an optical multiplexer without using optical fibers. The optical multiplexer may include an arrayed waveguide grating (AWG) or a reversed planar lightwave circuit (PLC) splitter and may be located in a multiplexer housing having at least one side wall with input apertures aligned with the mux input ports. The TOSA modules may include a base supporting at least a laser, laser driving circuitry, and a lens for focusing the light output from the laser. Z-rings may be used to facilitate alignment and to mount the TOSA bases to the side wall of the multiplexer housing, for example, by laser welding.

A multi-channel optical transmitter or transceiver uses a reversed planar lightwave circuit (PLC) splitter as an optical multiplexer to combine optical signals at different channel wavelengths into a multiplexed optical signal. The reversed PLC splitter includes splitter output ports that are used as the mux input ports and a splitter input port that is used as the mux output port. The mux input ports may be optically coupled to respective transmitter optical subassembly (TOSA) modules with or without optical fibers. The PLC splitter includes wavelength independent branched waveguides that combine the optical signals received on the mux input ports into the multiplexed optical signal on the mux output port.