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Optical signal demultiplexing device and optical signal demultiplexing method

a technology of optical signal and multi-plexing device, which is applied in the field of optical signal demultiplexing device and optical signal demultiplexing method, can solve the problem that high-level processes cannot be performed in the state of optical signal, and achieve the effect of increasing the pulse width of optical signal

Inactive Publication Date: 2008-11-20
FUJITSU LTD
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  • Abstract
  • Description
  • Claims
  • Application Information

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Benefits of technology

[0011]According to another aspect of the present invention, an optical signal demultiplexing method includes receiving an optical signal multiplexed by an optical time-division system and a synchronization pattern, and demultiplexing the optical signal based on the synchronization pattern; making the demultiplexed optical signals generate chirp; and increasing the pulse widths of the optical signals generating the chirp by passing the optical signals through a wavelength dispersion medium.

Problems solved by technology

However, according to the conventional technique described above, because the optical signal of each channel needs to be multiplexed and demultiplexed at a specified timing in the OTDM, there has been a problem in that high-level process cannot be performed in the state of the optical signal (for example, according to the conventional technique, only a path change can be performed in the state of the optical signal).

Method used

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  • Optical signal demultiplexing device and optical signal demultiplexing method
  • Optical signal demultiplexing device and optical signal demultiplexing method
  • Optical signal demultiplexing device and optical signal demultiplexing method

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first embodiment

[0042]FIG. 2 is a functional block diagram of a configuration of an optical demultiplexing device according to a As shown in FIG. 2, this optical demultiplexing device 100 includes an optical amplifier 101, a branch unit 102, an FSYN synchronization circuit 103, optical gates 104 to 107, and a pulse-length increasing unit 108. The optical amplifier 101, the branch unit 102, the FSYN synchronization circuit 103, and the optical gates 104 to 107 are similar to the optical amplifier 71, the branch unit 72, the FSYN synchronization circuit 73, and the optical gates 74 to 77, respectively, and therefore explanations thereof will be omitted.

[0043]Pulse-length increasing units 108 to 111 are processing units that increase pulse widths of the optical signals input from the optical gates 104 to 107. The pulse-length increasing units 108 to 111 have similar configurations. Therefore, the pulse-length increasing unit 108 is explained as an example, and the explanation of the pulse-length incr...

second embodiment

[0065]As described above, in the optical demultiplexing device 200 the optical amplifier 201 amplifies the optical signal multiplexed by the optical multiplexing device, and the branch unit 202 branches the amplified optical signal, and inputs the branched optical signals to the optical gates 204 to 207 and the FSYN synchronization circuit 203. The optical signals from the optical gates 204 to 206 are input to the wavelength converting units 208 to 210. The wavelength converting units 208 to 210 make the optical signals generate chirp. The wavelength multiplexer 211 multiplexes each optical signal. The pulse-length increasing unit 212 collectively increases the pulse width of the multiplexed optical signal, and the wavelength demultiplexer 213 demultiplexes the multiplexed optical signal. Therefore, the timings of the optical signals can be easily adjusted at low cost, and the demultiplexed optical signals can be OTDM multiplexed again in the state of light.

third embodiment

[0066]Next, characteristics of an optical demultiplexing device are explained. In demultiplexing the OTDM-multiplexed optical signal, signal synchronization for demultiplexing an optical signal from an ultrafast optical signal needs to be extracted. However, the currently available electric circuit has a slower response speed than that of the optical signal, and is very hard to extract the signal synchronization of the OTDM-multiplexed optical signal.

[0067]Therefore, the optical demultiplexing device according to the third embodiment converts the optical signal into an electric signal, by increasing the pulse width of the OTDM-multiplexed optical signal, and extracts the signal synchronization for demultiplexing the OTDM-multiplexed optical signal from the electric signal obtained by the conversion. Because the optical signal is converted into the electric signal by increasing the pulse width, even the currently available device (the electric circuit) having a slow response speed c...

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Abstract

An optical signal demultiplexing device includes a demultiplexing unit that receives an optical signal multiplexed by an optical time-division system and a synchronization pattern, and demultiplexes the optical signal based on the synchronization pattern. The optical signal demultiplexing device also includes a pulse-width increasing unit that makes optical signals demultiplexed by the demultiplexing unit generate chirp, and increases the pulse widths of the optical signals generating the chirp by passing the optical signals through a wavelength dispersion medium.

Description

BACKGROUND OF THE INVENTION[0001]1. Field of the Invention[0002]The present invention relates to an optical signal demultiplexing device that multiply demultiplexes an optical signal multiplexed by an optical time-division system.[0003]2. Description of the Related Art[0004]In recent years, in an optical fiber communication system, OTDM (Optical Time Division Multiplex) for time-division multiplexing optical signals directly in the state of light is being studied. According to this OTDM, when multiplexing optical signals, the optical signals are multiplexed at a timing assigned beforehand. When demultiplexing the multiplexed optical signal, multiplexed light is demultiplexed at a timing assigned beforehand. By multiplexing and demultiplexing the optical signals directly in the state of light by using the OTDM, a large capacitance of an efficient and economic network can be achieved.[0005]Japanese Patent Application Laid-open No. H7-221708 discloses a technique of compensating for a ...

Claims

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Application Information

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IPC IPC(8): H04J14/08H04B10/556G02F1/01G02F2/00H04B10/25H04B10/27H04B10/29H04B10/524H04B10/572
CPCH04J3/0605H04J14/086H04J14/08
Inventor IZUMI, FUTOSHI
Owner FUJITSU LTD