Optical transceiving apparatus, optical transmitting method, and optical transmitting device
An optical transceiving apparatus includes an optical transmitting device performing polarization multiplexing on and transmitting as polarization multiplexed signal light, a first signal light of a predetermined polarization direction and a second signal light of a polarization direction different from the predetermined polarization direction; an optical receiving device receiving the signal light transmitted from the optical transmitting device through an optical transmission path; an acquiring unit acquiring information indicative of magnitude relation of intensity between the first signal light and the second signal light included in the signal light received by the optical receiving device; and a control unit controlling the magnitude relation of intensity between the first signal light and the second signal light included in the signal light output from the optical transmitting device, to be opposite to the magnitude relation indicated by the information acquired by the acquiring unit.
1. An optical transmission system comprising:
an optical transmitting device performing polarization multiplexing on and transmitting as polarization multiplexed signal light, a first signal light of a predetermined polarization direction and a second signal light of a polarization direction different from the predetermined polarization direction;
an optical receiving device receiving the signal light transmitted from the optical transmitting device through an optical transmission path;
an acquiring unit acquiring information indicative of a ratio of intensity between the first signal light and the second signal light included in the signal light received by the optical receiving device; and
a control unit controlling the ratio of intensity between the first signal light and the second signal light included in the signal light output from the optical transmitting device such that a product of the ratio of intensity between the first signal light and the second signal light included in the signal light output and the ratio of intensity indicated by the information acquired by the acquiring unit comes close to a constant value, wherein
the first signal light is an X-polarized wave and the second signal light is a Y-polarized wave, and
the control unit changes the intensity of the X-polarized wave by an intensity manipulation amount X represented by the following equation:
X
=
(
TXout_Psig
_y
_pola
)
×
(
RXin_Psig
_y
_pola
)
-
(
TXout_Psig
_x
_pola
)
×
(
Rin_Psig
_x
_pola
)
(
TXout_Psig
_x
_pola
)
+
(
TXout_Psig
_y
_pola
)
+
(
RXin_Psig
_x
_pola
)
+
(
RXin_Psig
_y
_pola
)
where TXout Psig x pola is the intensity of the X-polarized wave transmitted from the optical transmitting device; TXout Psig y pola is the intensity of the Y-polarized wave transmitted from the optical transmitting device; RXin Psig x pola is the intensity of the X-polarized wave received by the optical receiving device; and RXin Psig y pola is the intensity of the Y-polarized wave received by the optical receiving device.
2. The optical transmission system according to claim 1 , wherein the constant value is one.
3. The optical transmission system according to claim 1 , comprising a superimposing unit superimposing onto at least one among the first signal light and the second signal light included in the signal light output, a signal component of a frequency that is different from the first signal light and the second signal light, wherein
the acquiring unit acquires the information indicative of the ratio, based on the intensity of the signal component included in the signal light received.
4. The optical transmission system according to claim 1 , wherein
the control unit adjusts the intensity of at least one among the first signal light and the second signal light polarization-multiplexed by the optical transmitting device, to control the ratio of intensity between the first signal light and the second signal light included in the signal light output.
5. The optical transmission system according to claim 1 , comprising an element inducing polarization dependent loss on the signal light output, wherein
the control unit rotates polarization of the signal light output, to control the ratio of intensity between the first signal light and the second signal light included in the signal light output.
6. The optical transmission system according to claim 1 , comprising a transmission side acquiring unit acquiring information indicative of a ratio of intensity between the first signal light and the second signal light included in the signal light output, wherein
the control unit, based on the ratio indicated by the information acquired by the acquiring unit and the ratio indicated by the information acquired by the transmission side acquiring unit, controls the ratio of intensity between the first signal light and the second signal light included in the signal light output.
7. The optical transmission system according to claim 1 , wherein the optical transmission path is an optical transmission path having polarization dependent loss.
8. An optical transmission method executed by a transmission system that includes an optical transmitting device performing polarization multiplexing on and transmitting as polarization multiplexed signal light, a first signal light of a predetermined polarization direction and a second signal light of a polarization direction different from the predetermined polarization direction and an optical receiving device receiving the signal light transmitted from the optical transmitting device through an optical transmission path, the optical transmission method comprising:
acquiring information indicative of a ratio of intensity between the first signal light and the second signal light included in the signal light received by the optical receiving device; and
controlling the ratio of intensity between the first signal light and the second signal light included in the signal light output from the optical transmitting device such that a product of the ratio of intensity between the first signal light and the second signal light included in the signal light output and the ratio of intensity indicated by the information acquired at the acquiring comes close to a constant value, wherein
the first signal light is an X-polarized wave and the second signal light is a Y-polarized wave, and
the controlling includes changing the intensity of the X-polarized wave by an intensity manipulation amount X represented by the following equation:
X
=
(
TXout_Psig
_y
_pola
)
×
(
RXin_Psig
_y
_pola
)
-
(
TXout_Psig
_x
_pola
)
×
(
Rin_Psig
_x
_pola
)
(
TXout_Psig
_x
_pola
)
+
(
TXout_Psig
_y
_pola
)
+
(
RXin_Psig
_x
_pola
)
+
(
RXin_Psig
_y
_pola
)
where TXout Psig x pola is the intensity of the X-polarized wave transmitted from the optical transmitting device; TXout Psig y pola is the intensity of the Y-polarized wave transmitted from the optical transmitting device; RXin Psig x pola is the intensity of the X-polarized wave received by the optical receiving device; and RXin Psig y pola is the intensity of the Y-polarized wave received by the optical receiving device.
9. An optical transmitting device comprising:
a polarization multiplexing unit performing polarization multiplexing on and outputting as polarization multiplexed signal light, a first signal light of a predetermined polarization direction and a second signal light of a polarization direction different from the predetermined polarization direction;
an acquiring unit acquiring information indicative of a ratio of intensity between the first signal light and the second signal light included in the signal light output from the polarization multiplexing unit through an optical transmission path and received by an optical receiving device; and
a control unit controlling the ratio of intensity between the first signal light and the second signal light included in the signal light output from the polarization multiplexing unit such that a product of the ratio of intensity between the first signal light and the second signal light included in the signal light output and the ratio of intensity indicated by the information acquired by the acquiring unit comes close to a constant value, wherein
the first signal light is an X-polarized wave and the second signal light is a Y-polarized wave, and
the control unit changes the intensity of the X-polarized wave by an intensity manipulation amount X represented by the following equation:
X
=
(
TXout_Psig
_y
_pola
)
×
(
RXin_Psig
_y
_pola
)
-
(
TXout_Psig
_x
_pola
)
×
(
Rin_Psig
_x
_pola
)
(
TXout_Psig
_x
_pola
)
+
(
TXout_Psig
_y
_pola
)
+
(
RXin_Psig
_x
_pola
)
+
(
RXin_Psig
_y
_pola
)
where TXout Psig x pola is the intensity of the X-polarized wave transmitted from the optical transmitting device; TXout Psig y pola is the intensity of the Y-polarized wave transmitted from the optical transmitting device; RXin Psia x pola is the intensity of the X-polarized wave received by the optical receiving device; and RXin Psig y pola is the intensity of the Y-polarized wave received by the optical receiving device.