摘要:
The optical transmitter comprises a light source which inputs continuous optical signal and a driving circuit which inputs driving signal to an optical modulator of Mach-Zehnder type. A photo coupler separates a part of the output of the optical modulator. A photo diode converts this part into electric signal. A band-pass filter and a pre-amplifier extract a frequency component of the driving signal contained in the electric signal. A mixer conducts synchronous detection between the driving signal and the extracted frequency component. Finally, a bias voltage control circuit controls a bias voltage based on a result of the phase comparison.
摘要:
The optical transmission apparatus has a Mach-Zehnder optical modulator, a light source for applying an optical signal of a continuous light to the optical modulator, a driving circuit for inputting a driving signal into the optical modulator, a branching filter for taking out a part of an output optical signal, a photodiode for converting the taken-out output optical signal into an electric signal, a band pass filter for extracting a frequency component of a driving signal included in this electric signal, an error signal generator circuit for generating an error signal of a bias voltage that minimizes a value of the extracted frequency component, and a bias voltage control circuit for applying a bias voltage added with this error signal to the optical modulator.
摘要:
In the multi-value modulation apparatus, one optical intensity detecting unit detects optical intensity of a modulation optical signal generated by one optical modulation signal generating unit and output from the variable optical attenuator. The detected optical intensity is provided to the comparator. Another optical intensity detecting unit detects optical intensity of a modulation optical signal output from another optical modulation signal generating unit. The attenuator attenuates the optical intensity detected by the another optical intensity detecting unit, and provides it to the comparator. The output of the comparator is provided to the optical variable attenuator as a control signal. The variable optical attenuator controls optical intensity of the modulation optical signal based on the control signal.
摘要:
A control-target-value setting unit sets a control target value corresponding to the number of multiplexed wavelengths measured by a number-of-multiplexed-wavelengths measuring unit. A controller controls the variable optical attenuator based on the control target value. An optical amplifier performs an optical amplification with a constant gain regardless of power of a wavelength-multiplexed light. The controller performs feedback control of the variable optical attenuator such that a result of measurement of the total power of the wavelength-multiplexed light coincides with the control target value.
摘要:
A control-target-value setting unit sets a control target value corresponding to the number of multiplexed wavelengths measured by a number-of-multiplexed-wavelengths measuring unit. A controller controls the variable optical attenuator based on the control target value. An optical amplifier performs an optical amplification with a constant gain regardless of power of a wavelength-multiplexed light. The controller performs feedback control of the variable optical attenuator such that a result of measurement of the total power of the wavelength-multiplexed light coincides with the control target value.
摘要:
An AWG (arrayed-waveguide grating/10A) divides input ports (11A1 to 11An+1−1) into 1 number of groups, each group comprising m number of input ports, and combines optical signals belonging to each of the groups. For example, the optical signals of wavelengths &lgr;1 to &lgr;m are input from the input ports (11A1 to 11Am) and output from an output port (12A1) as multiplex light. The multiplex light output in each of the groups in the above manner is input into a wave combination coupler (18A) and output to a transmission line (19A) as multiplex light of the optical signals of the wavelengths &lgr;1 to &lgr;n.
摘要:
An optical communication system including optical transmission systems each includes a transmission processing unit and a receiving processing unit, wherein the transmission processing unit includes an optical transmission unit that converts electric signals into optical signals, an auxiliary optical transmission unit that converts a part of the electric signals into an optical signal having a wavelength other than wavelengths of the optical signals generated by the optical transmission unit, and outputs the generated optical signal to a different transmission processing unit, and a wavelength multiplexing unit, and the receiving processing unit includes a wavelength demultiplexing unit, an optical receiving unit that converts the optical signals having the wavelengths of the optical signals generated by the optical transmission unit into electric signals, respectively, and an auxiliary optical receiving unit that converts the optical signal having the wavelength of the optical signal generated by the auxiliary optical transmission unit.
摘要:
An optical reception device realizes stabilization of reception sensitivity inexpensively and highly precisely. The optical reception device includes: a Mach-Zehnder type 1-bit delay unit including a one-terminal input port and two-terminal output ports for decoding an optical difference phase shift keying (DPSK) signal and provided with one or more phase control functions to control the phase state of light; photoelectric conversion means for branching a portion of an optical output signal output from the one-side output port of the Mach-Zehnder type 1-bit delay unit, to convert the branched portion into an electric signal; and a phase control unit for controlling the phase state of the Mach-Zehnder type 1-bit delay device by using as an error signal the output signal of the photoelectric conversion means.
摘要:
An optical reception device realizes stabilization of reception sensitivity inexpensively and highly precisely. The optical reception device includes: a Mach-Zehnder type 1-bit delay unit including a one-terminal input port and two-terminal output ports for decoding an optical difference phase shift keying (DPSK) signal and provided with one or more phase control functions to control the phase state of light; photoelectric conversion means for branching a portion of an optical output signal output from the one-side output port of the Mach-Zehnder type 1-bit delay unit, to convert the branched portion into an electric signal; and a phase control unit for controlling the phase state of the Mach-Zehnder type 1-bit delay device by using as an error signal the output signal of the photoelectric conversion means.
摘要:
Disclosed is a coating composition for a plastic label, which contains an oxetane compound, an epoxy compound, and a cyclic acetal and/or a poly(vinyl butyral). The coating composition excels in suitability for printing such as gravure printing or flexographic printing, cures rapidly to give excellent productivity, and after curing, gives a coating layer that excels in adhesion to a plastic base film and in toughness. A plastic label formed using the coating composition excels in surface scratch resistance and crumpling resistance, and therefore is particularly useful as a label for use in plastic containers, and metal containers such as bottle cans.