US 6,807,322 B2Granted

PMD compensating apparatus for controlling polarization controller based on detection of magnitude of waveform distortion

AssigneeMitsubishi Denki Kabushiki Kaisha

InventorsMasakazu Takabayashi, Sadayuki Matsumoto, Kiichi Yoshiara, Takuya Ohira, Junichiro Hoshizaki, Shigeru Matsuno, Ryosuke Namiki, Minoru Hashimoto

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Abstract

In a polarization mode dispersion compensating apparatus for controlling polarization mode dispersion of an optical signal, a first optical monitor detects and outputs, based on an optical signal outputted from a first optical transmission line having a grating, a first detection signal indicating magnitude of waveform distortion of the first optical transmission line, and a second optical monitor detects and outputs, based on an optical signal output from a second optical transmission line having a grating, a second detection signal indicating magnitude of waveform distortion of the second optical transmission line. A calculator circuit calculates from the first and second detection signals an output signal. A controller controls a polarization controller based on the output signal from the calculator circuit.

Claims20

Dependent claims

A polarization mode dispersion compensating apparatus comprising:

polarization control means for controlling polarization state of an optical signal so that a polarization axis of the optical signal becomes substantially coincident with an optical axis of an optical transmission line;
polarization splitting and combining means having first, second, and third ports, splitting an optical signal output from said polarization control means and input via the first port, into first and second optical signals having respective polarized wave components substantially perpendicular to each other, and outputting the first and second optical signals, respectively, via the second and third ports, said polarization splitting and combining means combining optical signals input via the second and third ports, and outputting a combined signal via the first port;
a first optical transmission line coupled to the second port of the polarization splitting and combining means and having a first grating, reflecting a first part of the first optical signal and transmitting a second part of the first optical signal and outputting the first part of the first optical signal to the second port of said polarization splitting and combining means;
a second optical transmission line coupled to the third port of the polarization splitting and combining means and having a second grating reflecting a first part of the second optical signal and transmitting a second part of the second optical signal and outputting the first part of the second optical signal to the third port of said polarization splitting and combining means;
first detection means connected to said first optical transmission line, said first detection means detecting and outputting, based on one of the first and second parts of the first optical signal output from said first optical transmission line, a first detection signal indicating magnitude of waveform distortion of the optical signal input to said first detection means;
second detection means connected to said second optical transmission line, said second detection means detecting and outputting, based on one of the first and second parts of the second optical signal output from said second optical transmission line, a second detection signal indicating magnitude of waveform distortion of the optical signal input to said second detection means;
first calculation means, receiving the first detection signal and the second detection signal individually, for calculating, based on the first detection signal and the second detection signal, and outputting an output signal;
and
first control means for controlling said polarization control means based on the output signal output by said first calculation means.

6 more elements

A polarization mode dispersion compensating apparatus comprising:

polarization control means for controlling polarization state of an optical signal so that a polarization axis of the optical signal becomes substantially coincident with an optical axis of an optical transmission line;
polarization splitting and combining means having first, second, and third ports, splitting an optical signal output from said polarization control means and input via the first port, into first and second optical signals having respective polarized wave components substantially perpendicular to each other, and outputting the first and second optical signals, respectively, via the second and third ports, said polarization splitting and combining means combining optical signals input via the second and third ports, and outputting a combined signal via the first port;
a first optical transmission line coupled to the second port of the polarization splitting and combining means and having a first grating, reflecting a first part of the first optical signal and transmitting a second part of the first optical signal and outputting the first part of the first optical signal to the second port of said polarization splitting and combining means;
a second optical transmission line coupled to the third port of the polarization splitting and combining means and having a second grating reflecting a first part of the second optical signal and transmitting a second part of the second optical signal and outputting the first part of the second optical signal to the third port of said polarization splitting and combining means;
and
control means provided on at least one of said first transmission line and said logical second transmission line, and controlling group delay time difference between the first and second optical signals having the respective polarized wave components substantially perpendicular to each other by processing an optical signal transmitted on at least one of said first optical transmission line and said second optical transmission line, wherein said control means comprises at least one of:
(a) means provided in at least one of said first and second gratings, and controlling a non-uniform distribution of temperature of at least one of said first and second optical transmission lines, in longitudinal directions of said first and second gratings;
(b) means provided in at least one of said first and second gratings, and controlling a non-uniform distribution of stress applied to at least one of said first and second optical transmission lines in the longitudinal directions of said first and second gratings;
and
(c) means provided in at least one of said first and second gratings, and controlling a non-uniform distribution of electric field applied to at least one of said first and second optical transmission lines in the longitudinal directions of said first and second gratings.

7 more elements

Dependencies are inferred from the claim text.

Facts

Application: 10/367,994Filed 19 Feb 2003
Priority: JP P2002-04143019 Feb 2002
Published: US 2003/0165284 A14 Sep 2003
Granted: 19 Oct 2004
Term ends: Not estimatedThe source records don’t support an estimate.

Classification8 codes

G02B 6/278
Characterised by their function or use, i.e. of the complete device: controlling polarisation mode dispersion [PMD], e.g. PMD compensation or…
G02B 6/2932
With a cascade of diffractive elements or of diffraction operations: comprising a directional router, e.g. directional coupler, circulator
G02B 6/4246
Packages, e.g. shape, construction, internal or external details: bidirectionally operating package structures
H04B 10/2569
For the reduction or elimination of distortion or dispersion: due to polarisation mode dispersion [PMD]