摘要:
Disclosed is an optical network which has: wavelength tunable optical transmitters of number MN, where N is an integer of two or more, each of which outputs an optical signal with arbitrary one of M wavelengths &lgr;1, &lgr;2, . . . , &lgr;M, where M is an integer of two or more, that are different from one another; a MN×N optical switch whose input ports are connected to the respective wavelength tunable optical transmitters of number MN, and which allows optical signals input to different input ports to be output form its same output port; 1×M optical wavelength demultiplexers of number N which output demultiplexing optical signal with wavelengths &lgr;1, &lgr;2, . . . , &lgr;M input from output ports of the MN×N optical switch into each wavelength; and optical receivers of number MN which receive optical signals input from the 1×M optical wavelength demultiplexers of number N.
摘要:
An optical communication transmission system including an optical amplifier lumped repeater system of the present invention includes, for the purpose of preventing degradation of the transmission characteristic arising from wavelength dispersion of optical fibers due to raised power of the optical signal, transmission optical fibers provided for all or most of the repeating sections and having wavelength dispersion values set to different values from zero, and optical fibers provided for the individual sections to compensate for the sum of wavelength dispersion of the sections so as to reduce the total wavelength dispersion to zero. The optical fiber for compensation for each section may be replaced by a substitutive compensation element. Alternatively, very small wavelength dispersion which remains due to failure in compensating to zero dispersion may be compensated for using a dispersion equalizer of an electric system in the reception section.
摘要:
An optical wavelength selector is provided that selects WDM channels from WDM optical signal and outputs each WDM channels from a plurality of ports. WDM optical signal in which m×n WDM channels are multiplexed is divided into n WDM channel groups and outputted by means of one wavelength-division demultiplexer. One WDM channel group is selected from the n WDM channel groups by means of n optical gate switches. The selected WDM optical signal is then separated into m WDM channels by wavelength and outputted by means of an optical wavelength router. As a result, m WDM channels of a specific WDM channel group can be received by m optical receivers.
摘要:
Disclosed are a datalink system, which has: a data transmission system which is composed of a parallel-to-serial converter which converts a parallel signal into a serial signal, a data transmission line which transmits the serial signal output from the parallel-to-serial converter and a serial-to-parallel converter which converts the serial signal transmitted through the data transmission line into the parallel signal; and a control signal transmission system which is composed of a control signal transmission line and lies in parallel with the data transmission system, and a communication network which has a data network and a control signal network.
摘要:
An optical filter having a transmission wavelength to be tuned dependent on light incident angle is rotatively provided in a collimated light path. The optical filter is rotated by the displacement of a piezoelectric actuator by a structure in which the displacement is converted to the rotation of the optical filter. The converting structure comprises a displacement magnifying mechanism for magnifying the displacement to provide the magnified displacement and a motion converting mechanism for converting the magnified displacement to the rotation of the optical filter.
摘要:
A signal light and a clock light which is generated by a clock light generator are propagated through a non-linear optical medium of, for instance, a silica based single mode optical fiber, from which the signal and clock lights and a four-wave mixing light are obtained. One light, for instance, the four-wave mixing light is extracted from the output lights of the non-linear optical medium, and a control signal which is dependent on a time-mean value in power of the extracted light is applied to a voltage controlled oscillator (VCO) for driving the clock light generator. Thus, a clock light which is locked in phase to the signal light is obtained. In case where the signal light comprises N time-division sequential lights (N=1, 2, 3, - - -), and a clock frequency of the clock light is 1/N of a clock frequency of the signal light, each one of the N time-division seaquential lights is shifted in phase or frequency by the non-linear optical medium, so that the phase or frequency shifted sequential light is switched to be demultiplexed by a switch device such as an optical coupler and a polarization beam splitter.
摘要:
A plurality of transmitting signal lights are supplied from a semiconductor laser light source which is modulated by a current having adjusted amplitude and phase injected thereinto in an optical transmitting apparatus. The signal lights are modulated in intensity by a plurality of external modulators, and a time-difference is applied among the signal lights. Thus, the signal lights are combined to provide a transmitting signal light which is propagated through a transmission line. At this time, a frequency component having a low transmission speed is supplied to the transmission line earlier than a frequency component having a fast transmission speed in compliance with a wavelength dispersion property of the transmission line.
摘要:
Supplied with an optical signal from a directly modulated semiconductor laser (11) in an optical transmitter, an optical frequency discriminator (15) converts a frequency modulated component of the optical signal to an intensity modulated component and produces an output optical beam which consists essentially of the intensity modulated component. Preferably, a negative feedback circuit (32, 33) is supplied in effect with the output optical beam representative of mark and space codes and controls the semiconductor laser and/or the optical frequency discriminator to keep the extinction ratio of the output optical signal at an optimum value such that the optical frequency discriminator has a transmissivity of about 90.degree./o for a predetermined one of the mark and space codes and a substantially zero transmissivity for the other of the mark and space codes.