摘要:
The invention, relates to a method for optical fiber communication. An optical signal having chirping determined by a chirp parameter is output to an optical fiber transmission line. The optical signal transmitted by the optical fiber transmission line is converted into an electrical signal. A bit error of the electrical signal is detected. Then, the chirp parameter is controlled so that the bit error detected above is reduced. According to this method, the chirp parameter is controlled so that the bit error detected is reduced. Accordingly, a chirping occurring in the optical fiber transmission line can be suppressed by the chirping of the optical signal to be output to the optical fiber transmission line, thereby compensating for chromatic dispersion and nonlinearity.
摘要:
The present invention relates to a method for optical fiber communication, and a terminal device and system for use in carrying out the method, and an object of the present invention is to compensate for chromatic dispersion and nonlinearity. A device for outputting an optical signal having a variable optical power into an optical fiber transmission line is provided. The optical signal transmitted by the transmission line is converted into an electrical signal by an optical receiver. A parameter related to waveform degradation of the electrical signal is detected by a monitor unit. A control unit controls the optical power of the optical signal to be output from the device so that the waveform degradation is improved.
摘要:
The present invention relates to an optical transmission device and an optical communication system applied to wavelength division multiplexing (WDM). The optical transmission device includes an optical multiplexer for wavelength division multiplexing a plurality of optical signals to generate WDM signal light and outputting the WDM signal light to an optical transmission line, a detecting unit for detecting a break of each optical signal according to the power of each optical signal, and a compensator for adding light having a predetermined wavelength to the WDM signal light when at least one of the optical signals is cut off. Through the structure of the present invention it becomes possible to prevent a deterioration in transmission quality in the case that the number of WDM channels is changed.
摘要:
An optical fiber transmission line composed of a plurality of segments each having a length falling within a predetermined range is provided. An optical transmitter for supplying an optical signal to the transmission line is provided at one end of the transmission line. An optical receiver for receiving the optical signal from the transmission line is provided at the other end of the transmission line. An optical amplifier is provided between any two adjacent ones of the segments. A dispersion compensator is provided in association with each of the optical transmitter, the optical receiver, and the optical amplifier. The dispersion compensator provides a dispersion selected from a plurality of stepwise varying dispersions determined according to the predetermined range.
摘要:
An optical amplifier relates to WDM (wavelength division multiplexing). The optical amplifier includes an optical amplifying unit, an ALC (automatic output level control) circuit for controlling the unit based on the output level thereof, and AGC (automatic gain control) circuit for controlling the unit based on the input and output levels thereof. A selecting circuit alternatively selects and operates the ALC and AGC circuits in accordance with a predetermined rule. Accordingly, the inconvenience occurring in the case of performing only one of ALC and AGC can be eliminated.
摘要:
The invention provides a wavelength multiplexing transmission apparatus includes a plurality of optical signal outputting sections for outputting optical signals having different wavelengths from each other, and a wavelength multiplexing section for wavelength multiplexing the optical signals outputted from the optical signal outputting sections and sending out a resulting optical signal. Each of the optical signal outputting sections includes a transmission light source driven by an electric signal for outputting an optical signal of a predetermined wavelength, and a wavelength filter capable of passing therethrough and sending out only an optical signal of the predetermined wavelength to be outputted from the transmission light source to prevent a wavelength drift of the optical signal outputted from the transmission light source. A variation of the wavelength of the transmission light source is detected, and the transmission light source is shut down in order to prevent otherwise possible crosstalk with another channel and prevent a further influence of the same.
摘要:
The invention provides a wavelength multiplexing transmission apparatus includes a plurality of optical signal outputting sections for outputting optical signals having different wavelengths from each other, and a wavelength multiplexing section for wavelength multiplexing the optical signals outputted from the optical signal outputting sections and sending out a resulting optical signal. Each of the optical signal outputting sections includes a transmission light source driven by an electric signal for outputting an optical signal of a predetermined wavelength, and a wavelength filter capable of passing therethrough and sending out only an optical signal of the predetermined wavelength to be outputted from the transmission light source to prevent a wavelength drift of the optical signal outputted from the transmission light source. A variation of the wavelength of the transmission light source is detected, and the transmission light source is shut down in order to prevent otherwise possible crosstalk with another channel and prevent a further influence of the same.
摘要:
The invention provides a wavelength multiplexing transmission apparatus includes a plurality of optical signal outputting sections for outputting optical signals having different wavelengths from each other, and a wavelength multiplexing section for wavelength multiplexing the optical signals outputted from the optical signal outputting sections and sending out a resulting optical signal. Each of the optical signal outputting sections includes a transmission light source driven by an electric signal for outputting an optical signal of a predetermined wavelength, and a wavelength filter capable of passing therethrough and sending out only an optical signal of the predetermined wavelength to be outputted from the transmission light source to prevent a wavelength drift of the optical signal outputted from the transmission light source. A variation of the wavelength of the transmission light source is detected, and the transmission light source is shut down in order to prevent otherwise possible crosstalk with another channel and prevent a further influence of the same.
摘要:
The present invention relates to an optical amplifier and an optical communication system applied to WDM (wavelength division multiplexing). The optical amplifier includes an optical amplifying medium to which WDM signal light obtained by wavelength division multiplexing a plurality of optical signals having different wavelengths is supplied, a pumping unit for pumping the optical amplifying medium such that the medium gives a gain to the WDM signal light, a feedback loop for controlling the pumping unit so that the gain is maintained constant, and an optical attenuator for giving a variable attenuation to the WDM signal light. Through the structure of the present invention, it becomes possible to provide an optical amplifier which can maintain constant the optical output level per channel of WDM and can maintain the gain characteristic constant.
摘要:
In an optical transmission system comprising a transmitter, a receiver, and a transmission line that connects the transmitter and the receiver, a dispersion compensator is disposed in the receiver. The transmitter comprises an E/O (electro-optical signal converter) and a post-amplifier. An optical signal that has been RZ-coded is supplied to the E/O. The transmitter pre-chirps the optical signal. The pre-chirp is performed by red-chirp of which the value of the chirping parameter α is positive. When the pre-chirp is performed, the non-linear effect of the optical signal on the transmission line can be canceled. In addition, with the RZ coded signal, the inter-symbol interference can be alleviated. Thus, the total dispersion amount of the dispersion compensator can be suppressed. In addition, the power of the optical output can be increased.