Optical transmission system using cross phase modulation

Patent metadata

Field	Value
Publication number	US-9077470-B2
Application number	US-201313767077-A
Country	US
Kind code	B2
Filing date	Feb 14, 2013
Priority date	Apr 6, 2012
Publication date	Jul 7, 2015
Grant date	Jul 7, 2015

Abstract

An optical transmission system includes: multiplex transmitting devices, each configured to modulate, with an optical carrier, a data signal modulated into light by an optical modulator in a non-linear optical medium arranged on a transmission path so as to multiplex the data signal into the optical carrier, the data signal having a frequency different in each of the multiplex transmitting devices; a receiving device configured to execute optical-to-electrical conversion on the optical carrier received from the transmission path so as to execute reception process of the data signals multiplexed by the multiplex transmitting devices; and a management device configured to specify a frequency band to be used, based on a modulation band of each of the optical modulators, and manage assignment of the frequency of each of the data signals within the frequency band to be used so as to avoid an effect of harmonics generated upon the optical-to-electrical conversion.

First claim

What is claimed is:

1. An optical transmission system comprising:
a plurality of multiplex transmitting devices, each configured to modulate, with an optical carrier, a data signal modulated into light by an optical modulator in a non-linear optical medium arranged on a transmission path through which the optical carrier is transmitted so as to multiplex the data signal into the optical carrier, the data signal having a frequency different in each of the plurality of multiplex transmitting devices;
a receiving device configured to execute optical-to-electrical conversion on the optical carrier received from the transmission path so as to execute reception process of the data signals multiplexed by the plurality of multiplex transmitting devices; and
a management device configured to specify a frequency band to be used, based on a modulation band that is common to all of the optical modulators, and manage assignment of the frequency of each of the data signals within the frequency band to be used such that a central frequency of a data signal is not assigned within a band of which a width is twice as large as a bandwidth to be used for another data signal and a frequency that is twice as high as the central frequency of an assigned signal is not used.

2. The optical transmission system according to claim 1 , wherein the management device assigns the frequency in order from an upper or lower limit for the frequency band to be used.

3. The optical transmission system according to claim 2 , wherein the management device determines a frequency to be assigned to a data signal to be newly multiplexed, based on an upper or lower limit for all assigned bands within the frequency band to be used and a bandwidth occupied by the data signal to be newly multiplexed.

4. The optical transmission system according to claim 3 , wherein
the management device has a management table in which the frequencies assigned to the data signals, bandwidths and usage information are stored for each of the plurality of multiplex transmitting devices, and
when any of the plurality of multiplex transmitting devices stops multiplexing a data signal, the management device updates, to an unused state, usage information corresponding to the multiplex transmitting device that stops multiplexing the data signal.

5. The optical transmission system according to claim 4 , wherein
if the management device determines, based on the usage information, that a band in an unused state exists in the frequency band to be used, the management device assigns a frequency within the band in the unused state to the data signal to be newly multiplexed.

6. The optical transmission system according to claim 1 , wherein
each of the plurality of multiplex transmitting devices multiplexes a request signal with a frequency in the frequency band to be used into the optical carrier when starting the multiplexing of the data signal, and
the management device assigns frequency to each of the data signals, based on each of the request signals received through the receiving device.

7. The optical transmission system according to claim 1 , wherein
each of the multiplex transmitting devices transmits request signal with a different wavelength from the optical carrier to the receiving device through the transmission path when starting the multiplexing of the data signal, and
the management device assigns frequency to each of the data signals, based on each of the request signals received through the receiving device.

8. The optical transmission system according to claim 1 , wherein the management device transmits each of response signals with a different wavelength from the optical carrier to each of the plurality of multiplex transmitting devices through the transmission path upon the assignment of the frequency to the data signal.

9. The optical transmission system according to claim 1 , wherein the management device specifies a frequency band that is to be used and is within a band that is higher than a central frequency of the modulation band of each of the optical modulators.

10. An optical transmission system comprising:
a plurality of multiplex transmitting devices, each configured to modulate, with an optical carrier, a data signal modulated into light by an optical modulator in a non-linear optical medium arranged on a transmission path through which the optical carrier is transmitted so as to multiplex the data signal into the optical carrier, the data signal having a frequency different in each of the plurality of multiplex transmitting devices;
a receiving device configured to execute optical-to-electrical conversion on the optical carrier received from the transmission path so as to execute reception process of the data signals multiplexed by the plurality of multiplex transmitting devices; and
a management device configured to specify a frequency band to be used, based on a modulation band that is common to all of the optical modulators, and manage assignment of the frequency of each of the data signals within the frequency band to be used, wherein assignment of the frequency of each of the data signals meets the following requirements,
N ·( F center− Fx/ 2)≧2·( F center+ Fx/ 2); and

F center≧( N+ 1)/{2·( N− 1)}· Fx , and

wherein Fmax is the modulation band common to all of the optical modulators, Fx is a width of the frequency band to be used, Fcenter is a central frequency of the frequency band, and N in an integer greater than or equal to 2.

Assignees

• Fujitsu Ltd

Inventors

• Kai Yutaka
• Watanabe Shigeki
• Okabe Ryou
• Kato Tomoyuki

Classifications

• H04J14/02 Primary

  Wavelength-division multiplex systems · CPC title

• H04J14/00 Primary

  Optical multiplex systems · CPC title

• H04J14/0256

  at the optical channel layer · CPC title

• H04J14/0298 Primary

  with sub-carrier multiplexing [SCM] · CPC title

• H04L5/003

  Arrangements for allocating sub-channels of the transmission path · CPC title