An optical communication system transmits information with a pumping light beam acting as the carrier, and with a signal light beam. This optical communication system includes an optical fiber amplifier adapted to amplify the signal light beam by having the signal light beam and the pumping light beam propagate through a rare-earth-doped fiber doped with a rare-earth element. A modulating circuit modulates the pumping light beam with a high-frequency modulating signal having a period shorter than the life span of fluorescence resulting from an excited state. When the signal light beam and the pumping light beam are propagated in the same direction through the rare-earth-doped fiber, the transmission of information with the pumping light beam acting as the carrier, can provide transmission of a supervisory signal for an optical repeater. When the signal light beam and the pumping light beam are propagated in opposite directions through the rare-earth-doped fiber, a two-way transmission can be achieved by the transmission of information with the signal light beam and the transmission of information with the pumping light beam.

Optical amplifier and optical communication system provided with the optical amplifier

Optical amplifier and optical communication system with optical amplifier using pumping light beam

Provided is a vehicle air conditioning device, in which a plurality of blow-off mode switching dampers are turned by a link mechanism, for enabling selective switching of blow-off modes, the link mechanism including: levers respectively provided to rotating shafts; and a turnable link including a plurality of cam grooves on each of which a pin provided to each lever slides A rail portion is provided in any one of an inner side surface of the cam groove and an outer peripheral surface of each pin, and the cam groove and the pin are in contact with each other through the rail portion Accordingly, it is possible to suppress abnormal noise that is generated when foreign substances are caught in a sliding surface (rail surface) between the cam groove and the pin

Vehicle air conditioning device

In a one-fiber bidirectional optical transmission system in which output optical signals of optical transmitter-receivers respectively connected to the opposite ends of one optical fiber transmission line are bidirectionally transmitted in the optical fiber transmission line, which utilizes a Raman amplification effect by backward pumping, a frequency satisfying the conditions of |fs1−f0|≠|fp2−f0| and |fs2−f0|≠|fp1−f0| is selected, where f0 is a zero dispersion frequency of the optical fiber transmission line, fs1 and fs2 are the frequencies of the first signal and the second signal, respectively, and fp1 and fp2 are frequencies of the first Raman pump light and the second Raman pump light, respectively.

One-core two-way optical transmission system

PURPOSE:To quicken the signal processing with simple constitution by providing an optical amplifier, an optical branch circuit, an optical clock extraction circuit, a optical confluencing circuit and an optical identification circuit and using them so as to process the 3R functions as the repeater at an optical level. CONSTITUTION:An optical input data signal is waveform-shaped by an optical amplifier 1 an branched into two at an optical branch circuit 2. On the other hand, one branch optical data signal is subject to optical clock signal extraction by an optical clock extraction circuit 3 to apply retiming. Furthermore, the other branched optical data signal is retarded so as to match the phase of the circuit 3 at the optical delay element 4. Then the output from the circuits 3, 4 is confluenced by the optical confluencing circuit 5 and identified at a prescribed optical threshold level by an optical identification circuits 6 and the optical data is reproduced. Then the 3R functions such as waveform shaping, retiming and repeater for identification and reproduction are processed entirely by the optical level in this way, then the signal processing is quickened with simple constitution.

Full optical processing repeater

PURPOSE:To obtain a waveform suitable for long-distance transmission and time division for an ultrahigh speed signal shaping and amplifying the waveform of an optical pulse, by providing an optical fiber inducing and scattering amplifying medium and an optically exciting mode synchronizing laser. CONSTITUTION:A part of an optical pulse 1 is transmitted by an optical branching device 2 to a timing extracting circuit 3. The circuit 3 extracts a clock frequency of the pulse 1, controls an optically exciting mode synchronizing laser 5 and synchronizes a mode synchronizing optical pulse 6 to the clock frequency. The pulses 1 and 6 are superimposed and made incident to an optical fiber inducing and scattering amplifying medium 8. From the exit light, an excited light transmitted at an optical branching device 9 is eliminated to obtain an optical pulse code train wave-shaped and amplified as an output signal 10.

Optical amplifier for wave shaping

PURPOSE:To extent the distance of transmission, by optically amplifying an optical signal which is transmitted to the opposite direction taking an optical signal transmitted unidirectionally as a stimulating light, with an optical fiber stimulated scattering amplification in an optical fiber. CONSTITUTION:A binary signal of, 100Mb/s from an input terminal 5 of the 1st optical transmitter/receiver 1 is given to an optical modulator 8 via a driver 7, where an output light of an Nd:YAG laser 9 having 1.32mum wavelength and +35dBm of output light level is modulated and the result is transmitted to an optical receiver 13 via a branching filter 4, an optical fiber 10, and a branching filter 12 of the 2nd optical transmitter/receiver 11. Further, a binary signal, 97Mb/s from a terminal 15 is converted into an optical signal having 0dBm of output light level at an InGaAsP semiconductor laser having 1.55mum wavelength and transmitted to the fiber 10 via the branching filter 12. This optical signal, 1.55mum of wavelength is amplified with fiber stimulated scattering by taking the optical signal of 1.32mum wavelength as a stimulated light by 30dB and given to an optical receiver 3.

Washio Kunihiko

Papers

Optical amplifier for wave shaping

Optical fiber bidirectional transmission system