Fujitsu Corporation

Hiroyuki Irie

Takeshi Hoshida

Toshiki Tanaka

Shoichiro Oda

Hiroshi Nakamoto

Takashi Nishida

Takayuki Kamoto

A transmission device includes a memory, and a processor coupled to the memory and configured to acquire a polarization mode dispersion value of each of wavelengths of a polarization-multiplexed optical signal having a wavelength, multiply a mean value of the polarization mode dispersion values of the wavelengths by a prescribed ratio, to thereby calculate a maximum value of the polarization mode dispersion value that is temporally varied, and select a multi-level modulation scheme of the polarization-multiplexed optical signal based on an index value of transmission quality of the polarization-multiplexed optical signal depending on the maximum value.

Transmission device and selection method for modulation scheme

An optical transmission device includes: a memory; and a processor coupled to the memory; the processor: generate a first symbol by mapping a transmission data series to a first signal point which belongs to a first group within a signal space defined with regard to characteristics of an optical carrier wave of the transmission data series; generate a second symbol by mapping the transmission data series to a second signal point belonging to a second group; calculate a perturbation quantity of a signal electric field for each of the first and second symbols based on signal electric field vector information of a symbol which is generated before the first symbol and the second symbol; and determine, as a transmission signal, a symbol having a smaller perturbation quantity between the first symbol and the second symbol.

Optical transmission device and optical transmission method

A signal processing circuit generates first to fourth drive signals to which first to fourth fixed pattern are respectively added. An optical modulators generate a first polarization multiplexed optical signal of a first wavelength from the first and second drive signals and a second polarization multiplexed optical signal of a second wavelength from the third and fourth drive signals. The first to third fixed patterns are the same as one another, and a value of each bit of the fourth fixed pattern is inverted with respect to a value of a corresponding bit of the third fixed pattern. The signal processing circuit generates the first to fourth drive signals such that the first to fourth fixed patterns are transmitted at the same or approximately the same time by the first polarization multiplexed optical signal and the second polarization multiplexed optical signal.

Optical transmission device and wavelength division multiplexing optical transmission device

A polarization fluctuation compensation device, when WDM light received by, for example, an optical reception device includes a polarization scrambled optical signal and a non-polarization scrambled optical signal, collects information related to whether optical signals having respective wavelengths are polarization scrambled, obtains a target value of control parameters which are different from each other, according to the speed of polarization fluctuations in the non-polarization scrambled optical signal based on the collected information, and performs reception processing of the non-polarization scrambled optical signal by using a control parameter set as the target value. As a result, an influence of fast polarization fluctuations generated resulting from an interaction between optical signals having respective wavelengths can be reliably compensated for, thereby enabling to realize excellent reception characteristics.

Polarization fluctuation compensation device and optical communication system

A communication system for efficient sales promotion of a product or a service is provided. An information providing site is provided with a simple diagnosis processing portion for performing a simple skin diagnosis of a user of a terminal device, a simple result transmitting portion for transmitting simple diagnosis data and an ID key to the user, and a customer data extracting portion for transmitting private data and the simple diagnosis data to a service providing site. The service providing site is provided with an ID key receiving portion for receiving the ID key from the user, a customer data requesting portion for transmitting the ID key to the information providing site, and a customer data receiving portion for receiving private data corresponding to the ID key. The customer data extracting portion transmits private data corresponding to the ID key transmitted by the customer data requesting portion.

Communication system, information agent method and recording medium

Disclosed herein is a method for level equalization. In this method, a first optical amplifier having a gain tilt coefficient defined as a change in gain tilt to a unit change in gain is first provided. A second optical amplifier having a gain tilt coefficient different from the gain tilt coefficient of the first optical amplifier is cascaded to the first optical amplifier. The gains of the first and second optical amplifiers are distributed so that a level tilt of light amplified by the first and second optical amplifiers becomes substantially flat. Thus, it is possible to provide a simple method for allowing automatic level equalization by providing a plurality of optical amplifiers having different gain tilt coefficients and distributing the gains of these optical amplifiers so that a level tilt of light amplified by these optical amplifiers becomes substantially flat.

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Kawasaki, Japan

Hiroyuki Irie