摘要:
A wavelength division multiplexed optical processing device and an optical communication transmission path which are capable of significantly improving the transmission characteristic of wavelength division multiplexed optical signals. A wavelength division multiplexed optical processing device is formed by a first arrayed optical waveguide for demultiplexing entered wavelength division multiplexed optical signals, and outputting demultiplexed optical signals; a plurality of correction units for correcting respective optical signals demultiplexed by the first arrayed optical waveguide; and a second arrayed optical waveguide for multiplexing optical signals corrected by the correction unit, and outputting multiplexed optical signals. An optical communication transmission path is formed by an optical transmission path; and at least one wavelength division multiplexed optical processing device using an arrayed optical waveguide having a transmission wavelength characteristic with a flat top shape, which is inserted into the optical transmission path at a prescribed interval.
摘要:
An optical transmitter which reverses the ON-OFF state of the optical intensity of a bright soliton lightwave and generates a dark soliton lightwave having an optical phase shift, an optical receiver for the dark soliton lightwave, and a superfast, high-capacity optical transmission system which is capable of increasing the soliton pulse array density while suppressing timing jitter. The optical transmission system is provided with the optical transmitter which transmits a dark soliton lightwave having digital information, the optical receiver which receives the dark soliton lightwave as a return-to-zero pulse and a transmission optical fiber interconnecting the transmitter and the receiver. The system has a construction in which the transmission optical fiber has, at the wavelength of the transmission lightwave, a normal dispersion value which makes negative the average wavelength dispersion value over the entire length of the optical fiber, and the average value of the wavelength dispersion value and the optical output intensity of the transmission optical fiber have values so that a non-linear optical effect and a wavelength dispersion effect, which are exerted on the transmission lightwave, are balanced with each other.
摘要:
An optical amplifying-repeating transmission system is disclosed which is composed of an optical fiber for transmitting a lightwave signal with digital information added to return-to-zero lightwave pulses and a plurality of optical amplifying repeaters inserted in the optical fiber for transmission use. The mean value of wavelengths at which the wavelength dispersion of the optical fiber is zero is smaller than the wavelength of the lightwave signal which is transmitted over the system. The accumulated wavelength dispersion value of the optical fiber tends to increase with the distance of transmission, from a macroscopic viewpoint. The optical fiber for transmission is divided into a plurality of sections. In accordance with the accumulated wavelength dispersion value of the optical fiber in each section except at least the last one, a wavelength dispersion medium, which locally changes the wavelength dispersion in a manner to cancel the accumulated wavelength dispersion in the section at the wavelength of the lightwave signal, is inserted in the section to eliminate the accumulation of the timing jitter.
摘要:
A new two-way WDM optical transmission system is provided. The WDM optical transmission system comprises a two-way optical fiber cable, a first dispersion compensation optical fiber (DCOF) connected to one end of the optical fiber cable, a second DCOF connected to another end of the optical fiber cable, a chromatic dispersion compensating transmitter unit and a chromatic dispersion compensating receiver unit. The two-way optical fiber cable comprises a plurality of segments. The first DCOF is connected to one end of the optical fiber cable and has a compensation amount of a half of a one segment dispersion D.sub.c of the optical fiber cable. The second DCOF is connected to another end of the optical fiber cable and has the compensation amount of the half of the one segment dispersion D.sub.c. And the chromatic dispersion compensating transmitter unit compensates accumulated residual chromatic dispersions to be caused by higher-order wavelength dispersion of the optical fiber cable at each signal wavelength. Further, the chromatic dispersion compensating receiver unit compensates accumulated residual chromatic dispersions caused by higher-order wavelength dispersion of the optical fiber cable at each signal wavelength. The chromatic dispersion compensating transmitter unit has a plurality of optical transmitters, a multiplexer combining a plurality of different wavelength bands and a plurality of chromatic dispersion compensators. And the chromatic dispersion compensating receiver unit has a demultiplexer, a plurality of optical receiver and a plurality of chromatic dispersion compensators.
摘要:
An optical transmission system comprises transmission optical fibers 14 connected between an optical transmission terminal 10 and an optical receiving terminal 12 via optical amplifying repeaters 16, and equalizing fiber 18 each connected in each equalizing interval. The equalizing fiber 18 is typically located at the terminal end of each equalizing interval. Each transmission optical fiber 14 is a dispersion-shifted fiber whose wavelength dispersion is substantially zero in a specific band, for example, 1.5 .mu.m. The optical amplifying repeaters 16 include an optical amplifier, and a dispersion compensating optical element having wavelength dispersion characteristics that exhibit an inclination opposite from that of wavelength characteristics of wavelength dispersion of the transmission optical fiber 14 (more specifically, a minus inclination with respect to the wavelength). The dispersion compensating optical element compensates offset values of cumulative wavelength dispersion among different wavelengths. The dispersion compensating optical element can be made by a fiber grating technology.
摘要:
An optical communication system of a construction wherein the average wavelength dispersion value of the transmission optical fiber used, the optical output intensity of each optical amplifier repeater inserted in the transmission optical fiber and the widths of return-to-zero optical pulses transmitted over the transmission line are determined so as to compensate for the pulse compression effect by the nonlinear optical effect produced on the optical pulses by the pulse spreading effect by the wavelength dispersion effect. An optical multiplexer in the optical transmitting device time-division multiplexes the return-to-zero optical pulses, and the optical multiplexed signal is provided as an alternating-amplitude optical signal with the amplitudes of the return-to-zero optical pulses alternated.
摘要:
This invention provides the gain equalizer positioned to an optical amplifying transmission line for equalizing gains of said optical amplifying transmission line, comprising a plurality of first optical filters varying transmittance periodically in at least predetermined wavelength range, and one or more second optical filters that their transmittance peaks at a wavelength substantially coinciding to the predetermined transmittance bottom wavelength of the first optical filters and decreases in a predetermined range at both side of the predetermined transmittance bottom wavelength.
摘要:
An optical transmitter which reverses the ON-OFF state of the optical intensity of a bright soliton lightwave and generates a dark soliton lightwave having an optical phase shift, an optical receiver for the dark soliton lightwave, and a superfast, high-capacity optical transmission system which is capable of increasing the soliton pulse array density while suppressing timing jitter. The optical transmission system is provided with the optical transmitter which transmits a dark soliton lightwave having digital information, the optical receiver which receives the dark soliton lightwave as a return-to-zero pulse and a transmission optical fiber interconnecting the transmitter and the receiver. The system has a construction in which the transmission optical fiber has, at the wavelength of the transmission lightwave, a normal dispersion value which makes negative the average wavelength dispersion value over the entire length of the optical fiber, and the average value of the wavelength dispersion value and the optical output intensity of the transmission optical fiber have values so that a non-linear optical effect and a wavelength dispersion effect, which are exerted on the transmission lightwave, are balanced with each other.
摘要:
An optical transmission system which permits long-distance, ultrafast, high-capacity optical soliton transmission by suppressing timing jitter with simple means. In an optical transmission system which uses a transmission line composed of an optical fiber for transmitting therethrough a lightwave signal having digital information added to a return-to-zero lightwave pulse and a plurality of optical amplifying repeaters for compensating for losses by the optical fiber and in which the pulse compression effect by the nonlinear optical effect on the optical pulse and the pulse expansion effect by the dispersion effect are compensated, at least one optical band limited element which has a flat group delay characteristic near the center frequency is disposed in the transmission line at intervals of a period Z equal to the soliton period Z.sub.sol and the product, aB.sub.sol.spsb.2, of the curvature a of the product of the intensity transfer funtions of the optical band limited elements in the vicinity of the center frequency in the soliton period and the square of the full width at half maximum, B.sub.sol, of the spectrum of the lightwave pulse to be transmitted is set to a value in the range of 2.1.times.10.sup.-2 to 8.3.times.10.sup.-2.
摘要:
An optical amplifying transmission system is disclosed in which a large quantity of optical fiber whose zero dispersion wavelength is longer than the wavelength of the lightwave signal is introduced to provide an RZ lightwave signal transmission system. In this system, the average zero dispersion wavelength by the optical fiber is shorter than the wavelength of the lightwave signal, the zero dispersion wavelength by the optical fiber whose length is in the range of one-thirds to two-thirds of the entire length of the optical fiber is longer than the wavelength of the lightwave signal, and the absolute value of the wavelength dispersion is larger than one-half the absolute value of the average wavelength dispersion value over the entire length of the optical fiber.