Systems and methods for optical modulation index calibration in a CATV network.

An optical reception apparatus (1) of the present invention includes: a local oscillator (11) outputting local oscillation light (22); an optical mixer (12) receiving a multiplexed optical signal (21) and the local oscillation light, and selectively outputting an optical signal (23) corresponding to the wavelength of the local oscillation light from the multiplexed optical signal; a photoelectric converter (13) converting the optical signal (23) output from the optical mixer into an electric signal (24); a variable gain amplifier (15) amplifying the electric signal (24) to generate an output signal (25) whose output amplitude is amplified to a certain level; a gain control signal generating circuit (16) generating a gain control signal (26) for controlling the gain of the variable gain amplifier (15); and a monitor signal generating unit (17) generating a monitor signal (27) corresponding to the power of the optical signal (23) using the gain control signal (26).

Described herein are photonic integrated circuits (PICs) comprising a semiconductor optical amplifier (SOA) to output a signal comprising a plurality of wavelengths, a sensor to detect data associated with a power value of each wavelength of the output signal of the SOA, a filter to filter power values of one or more of the wavelengths of the output signal of the SOA, and control circuitry to control the filter to reduce a difference between a pre-determined power value of each filtered wavelength of the output signal of the SOA and the detected power value of each filtered wavelength of the output signal of the SOA.

An optical carrier selector system is provided for selecting a wanted carrier signal from a multi-carrier signal comprising a plurality of carrier signals. The optical carrier selector system comprises a series of optical filter devices. Each optical filter device of the series comprises an input port for receiving a signal comprising two or more carrier signals, each optical filter device being configured to filter out an unwanted carrier signal. Each optical filter device also comprises an output port for outputting at least the wanted carrier signal and any remaining signals that have not been filtered out by that particular optical filter device, and a drop port for outputting the unwanted carrier signal that is being filtered out by the respective optical filter device. By outputting from a drop port the unwanted carrier signal that is being filtered out by the respective optical filter device, this has the advantage of enabling the operation of the optical carrier selector system to be monitored for proper operation, and controlled or adjusted if necessary.

An optical transmission apparatus including: an attenuator that attenuates a power of a first optical signal generated in a first modulation method to a first target level and attenuates a power of a second optical signal generated in a second modulation method, a modulation level in the second modulation method being lower than the modulation level in the first modulation method, to a second target level, the second target level being lower than the first target level; and a transmitter that sends a WDM signal including the first optical signal and the second optical signal that have been attenuated by the attenuator.

A communication system includes a first optical system and a second optical system optically connected to a clamping laser and a pump laser. The first optical system includes first and second optical splitters. The first optical splitter is configured to receive a clamping laser signal from the clamping laser and split the signal into split clamping laser signals. The second optical splitter is configured to receive a pump laser signal from the pump laser and split signal into split pump laser signals. The second optical system is optically connected to the first optical system and includes amplifier systems. Each amplifier system is configured to receive a multiplexed signal. The second optical system includes first and second combiners optically connected to an erbium-doped fiber. The first combiner is optically connected to the first splitter, and the second combiner is optically connected to the second splitter.

A transmission apparatus includes a signal power detector configured to detect signal power of a wavelength-multiplexed optical signal to be transmitted to a transmission line, a variable optical attenuator configured to attenuate the wavelength-multiplexed optical signal, and a processor configured to control an attenuation amount of the variable optical attenuator according to the signal power and whether a Raman amplifier in which pumping light is inputted to the transmission line exists.

Example embodiments of the present invention relate to An optical node comprising of at least two optical degrees; a plurality of directionless add/drop ports; and at least one wavelength equalizing array, wherein the at least one wavelength equalizing array is used to both select wavelengths for each degree, and to perform directionless steering for the add/drop ports.

A method may include interleaving, by an optical device, a set of bits of a first channel with a set of bits of a second channel. The first channel may include first forward error correction (FEC) data associated with the set of bits of the first channel and the second channel may include second FEC data associated with the set of bits of the second channel. The method may further include transmitting first information via the first channel and second information via the second channel. The first information may include a portion of the set of bits of the first channel, a portion of the set of bits of the second channel, and the first FEC data. The second information may include another portion of the set of bits of the first channel, another portion of the set of bits of the second channel, and the second FEC data.

Methods and systems for amplifying optical signals include generating idler signals for input signals using an optical pump at a first Bragg reflection waveguide (BRW) having second order optical nonlinearity. Phase and amplitude regulation is performed using the output from the first BRW. Optical power monitoring of the input signals may be used for power equalization. The phase-sensitive amplified signal is generated at a second BRW using the optical pump. Optical power monitoring of the input signals may be used for power equalization.