摘要:
A delay device that provides a delay amount to at least one of the in-phase signal and the quadrature signal, and a delay control section that controls the delay amount provided by the delay device based on a quality of the signals when the in-phase signal and the quadrature signal, to the at least one of which the delay amount is provided, at the delay device are converted into digital signals by the analog-digital converter, and the digital signal processing is carried out at the processor are provided. Thereby, the signal quality of recovered data at a receiving end of a multi-level phase modulation communication system is improved.
摘要:
There is provided an optical network system in which optical signals modulated by each of at least two modulation methods are wavelength-division-multiplexed and transferred, including: an optical transmitter configured to transmit first optical signals modulated by each of at least two modulation methods; an add-drop multiplexer configured to drop second optical signals from wavelength-division-multiplexed optical signals transferred in the optical network system, and add the first optical signals to the wavelength-division-multiplexed optical signals; an optical receiver configured to demodulate the second optical signals corresponding to each of at least two modulation methods; and a controller configured to control wavelengths of the first optical signals, the second optical signals and the wavelength-division-multiplexed optical signals so as to rearrange wavelengths of the first optical signals, the second optical signals and the wavelength-division-multiplexed optical signals so that optical signals modulated by a same modulation method are placed on an adjacent wavelength.
摘要:
An optical modulation apparatus includes a first modulator, a second modulator, a multiplexer, a calculator and an adjustor. The first modulator configured to modulate light emitted by a light source using a first input signal and output a first modulated signal. The second modulator configured to modulate the light using a second input signal and output a second modulated signal. The multiplexer configured to multiplex the first and second modulated signals and output a multiplexed signal. The calculator configured to calculate a power difference between a higher-side frequency component having a frequency higher than a center frequency of the multiplexed signal and a lower-side frequency component having a frequency lower than the center frequency. The adjustor configured to adjust delays of the first and second input signals based on the power.
摘要:
A communication system includes a transmitter, a receiver device, and a control circuit. The transmitter transmits an optical signal. The receiver device receives the optical signal. The control circuit reduces a power consumption of the receiver device based on an accumulated chromatic dispersion of the received optical signal. The receiver device includes a receiver, an analog/digital converter, and a digital signal processor. The receiver extracts a signal indicating a complex amplitude of the optical signal. The analog/digital converter converts the signal indicating the complex amplitude into a digital signal. The digital signal processor digitally-processes the digital signal.
摘要:
A delay device that provides a delay amount to at least one of the in-phase signal and the quadrature signal, and a delay control section that controls the delay amount provided by the delay device based on a quality of the signals when the in-phase signal and the quadrature signal, to the at least one of which the delay amount is provided, at the delay device are converted into digital signals by the analog-digital converter, and the digital signal processing is carried out at the processor are provided. Thereby, the signal quality of recovered data at a receiving end of a multi-level phase modulation communication system is improved.
摘要:
An optical modulation device and method thereof is provided. The optical modulation device includes a decision circuit making a decision with respect to an input data signal in accordance with a timing of a first clock signal, a first modulator modulating light output based on the data signal by the decision circuit; a second modulator modulating the modulated light in accordance with a timing of a second clock signal; and delay controller delaying the first clock signal within a range of a phase margin of a decision circuit, and delaying the second clock signal, thereby controlling a state of a phase difference between the data signal and the second clock signal.
摘要:
The disclosed device and method include varying phases of two data signals at a first predetermined frequency, performing multi-level phase modulation of a light based on the two data signals whose phases are varied at the first predetermined frequency, extracting a component having the first predetermined frequency from an optical signal subjected to the phase modulation, and controlling the phases of the two data signals based on the component extracted from the optical signal.
摘要:
An optical modulation apparatus includes a first modulator, a second modulator, a multiplexer, a detector and an adjustor. The first modulator modulates light emitted by a light source using a first input signal and outputs a first modulated signal. The second modulator modulates the light using a second input signal and outputs a second modulated signal. The multiplexer multiplexes the first and second modulated signals and outputs a multiplexed signal. The detector is configured to detect a dip where power in a waveform of the multiplexed signal is equal to or smaller than a predetermined value. The adjustor is configured to adjust a delay of the first and second input signals based on power at the dip.
摘要:
There is provided an optical network system in which optical signals modulated by each of at least two modulation methods are wavelength-division-multiplexed and transferred, including: an optical transmitter configured to transmit first optical signals modulated by each of at least two modulation methods; an add-drop multiplexer configured to drop second optical signals from wavelength-division-multiplexed optical signals transferred in the optical network system, and add the first optical signals to the wavelength-division-multiplexed optical signals; an optical receiver configured to demodulate the second optical signals corresponding to each of at least two modulation methods; and a controller configured to control wavelengths of the first optical signals, the second optical signals and the wavelength-division-multiplexed optical signals so as to rearrange wavelengths of the first optical signals, the second optical signals and the wavelength-division-multiplexed optical signals so that optical signals modulated by a same modulation method are placed on an adjacent wavelength.
摘要:
In an optical modulator, a DQPSK modulating section, a waveguide optical amplifying section, and an RZ modulating section are cascade connected on an optical path between input and output ports, and power of RZ-DQPSK signal light output from the output port is monitored by a photodetector, to feed-back control the waveguide optical amplifying section by an output control section so that the monitored power becomes constant at a target level. As a result, a small and low-cost optical modulator that can reliably compensate respective losses in a phase modulating section and an intensity modulating section, and differences of the respective losses, can be realized.