Mitsubishi Denki Kabushiki Kaisha

Kaoru Kinjo

Takashi Mizuochi

Satoshi Kajiya

Kazuyuki Ishida

A differential encoder generates a differentially encoded signal based on a data signal. An RZ (return to zero) encoder generates an electric RZ differential signal as an RZ signal in an electric area based on the differentially encoded signal. A Mach-Zehnder interferometer type intensity modulator generates an optical RZ-DSPK (differential phase shift keying) signal as an RZ signal in an optical area based on the electric RZ differential signal.

Optical transmitter

Two signal lights having different wavelengths are bidirectionally transmitted on an optical-fiber transmission-line. A Raman pump light source generates a first Raman pump light having predetermined wavelengths with a Raman gain-bandwidth for amplifying the first signal light and without response to the second signal light. Another Raman pump light source generates a second Raman pump light having predetermined wavelengths with a Raman gain-bandwidth for amplifying the second signal light and without response to the first signal light. The first Raman pump light and the second Raman pump light are differently injected from respective input/output terminals into the optical-fiber transmission-line by optical combining and branching filters.

Method of and device for performing bi-directional transmission using a single-wire

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 |f&#x2212;f|&#x2260;|f&#x2212;f| and |f&#x2212;f|&#x2260;|f&#x2212;f| is selected, where fis a zero dispersion frequency of the optical fiber transmission line, fand fare the frequencies of the first signal and the second signal, respectively, and fand fare frequencies of the first Raman pump light and the second Raman pump light, respectively.

Growing community of inventors

Tokyo, Japan

Kaoru Kinjo