Optical transmission method and apparatus
This application provides an optical transmission method and apparatus, and relates to the communication field. A first optical transmission apparatus includes a first circulator and a first receiving module. The first receiving module is connected to the first circulator. The first circulator is configured to receive a second unmodulated optical signal from a second optical transmission apparatus. The first receiving module is configured to receive a second modulated optical signal from the second optical transmission apparatus, and receive the second unmodulated optical signal from the first circulator. The second modulated optical signal is obtained by modulating a first unmodulated optical signal, the second unmodulated optical signal is used to perform coherence detection on the second modulated optical signal, and the third unmodulated optical signal is an optical signal provided by the first optical transmission apparatus to the second optical transmission apparatus.
1 . A first optical transmission apparatus, comprising:
a first circulator, configured to receive a second unmodulated optical signal from a second optical transmission apparatus; and
a first receiver, connected to the first circulator, and configured to:
receive a second modulated optical signal from the second optical transmission apparatus; and
receive the second unmodulated optical signal from the first circulator, wherein the second modulated optical signal is obtained by modulating a first unmodulated optical signal, the second unmodulated optical signal is used to perform coherence detection on the second modulated optical signal, the first unmodulated optical signal and the second unmodulated optical signal are obtained by separating a third unmodulated optical signal, and the third unmodulated optical signal is provided by the first optical transmission apparatus to the second optical transmission apparatus.
2 . The first optical transmission apparatus according to claim 1 , wherein the first circulator is further connected to a second circulator, and the second optical transmission apparatus comprises the second circulator; and
wherein the first circulator being configured to receive the second unmodulated optical signal from the second optical transmission apparatus comprises the first circulator being configured to: receive the second unmodulated optical signal from the second circulator.
3 . The first optical transmission apparatus according to claim 1 , further comprising:
a first polarization controller, connected to the first circulator, wherein the first polarization controller is configured to control polarization of the second unmodulated optical signal, to obtain the second unmodulated optical signal on which polarization control is performed.
4 . The first optical transmission apparatus according to claim 3 , wherein the second unmodulated optical signal being used to perform coherence detection on the second modulated optical signal comprises:
the second unmodulated optical signal on which polarization control is performed is used to perform coherence detection on the second modulated optical signal.
5 . The first optical transmission apparatus according to claim 3 , wherein the first polarization controller is further configured to control polarization of a first modulated optical signal, wherein the first modulated optical signal is sent by the first optical transmission apparatus to the second optical transmission apparatus.
6 . The first optical transmission apparatus according to claim 5 , further comprising:
a first transmitter, connected to the first circulator, and configured to send the first modulated optical signal to the first polarization controller through the first circulator.
7 . The first optical transmission apparatus according to claim 1 , wherein:
the first optical transmission apparatus is on an active antenna unit (AAU) side, and the second optical transmission apparatus is on a baseband unit (BBU) side; or
the first optical transmission apparatus is on a BBU side, and the second optical transmission apparatus is on an AAU side.
8 . A second optical transmission apparatus, comprising:
a second coupler, configured to separate a third unmodulated optical signal into at least a first unmodulated optical signal and a second unmodulated optical signal, wherein the third unmodulated optical signal is provided by a first optical transmission apparatus;
a second transmitter, connected to the second coupler, and configured to send a second modulated optical signal to the first optical transmission apparatus, wherein the second modulated optical signal is obtained by modulating the first unmodulated optical signal; and
a second circulator, connected to the second coupler, and configured to receive the second unmodulated optical signal from the second coupler, and send the second unmodulated optical signal to the first optical transmission apparatus, wherein the second unmodulated optical signal is used for coherence detection of the second modulated optical signal.
9 . The second optical transmission apparatus according to claim 8 , wherein the second circulator is further connected to a first circulator, and the first optical transmission apparatus comprises the first circulator; and
wherein the second circulator being configured to send the second unmodulated optical signal to the first optical transmission apparatus comprises the second circulator being configured to: send the second unmodulated optical signal to the first circulator.
10 . The second optical transmission apparatus according to claim 8 , further comprising:
a second polarization controller, connected to the second coupler, and configured to control polarization of the third unmodulated optical signal.
11 . The second optical transmission apparatus according to claim 10 , wherein the second coupler being configured to separate the third unmodulated optical signal into at least the first unmodulated optical signal and the second unmodulated optical signal comprises the second coupler being configured to:
separate the third unmodulated optical signal on which polarization control is performed into at least the first unmodulated optical signal and the second unmodulated optical signal.
12 . The second optical transmission apparatus according to claim 10 , wherein the second coupler is further configured to separate the third unmodulated optical signal on which polarization control is performed into a fifth unmodulated optical signal, the fifth unmodulated optical signal is used for coherence detection of a first modulated optical signal, and the first modulated optical signal is transmitted by the first optical transmission apparatus to the second optical transmission apparatus.
13 . The second optical transmission apparatus according to claim 12 , further comprising:
a second receiver, connected to both the second circulator and the second coupler, and configured to receive the first modulated optical signal from the first optical transmission apparatus through the second circulator, and receive the fifth unmodulated optical signal from the second coupler.
14 . The second optical transmission apparatus according to claim 10 , wherein the second polarization controller is further connected to the second transmitter, and is configured to control polarization of the second modulated optical signal.
15 . The second optical transmission apparatus according to claim 14 , further comprising:
a third circulator;
wherein the second polarization controller being connected to the second coupler comprises:
the second polarization controller being connected to the second coupler through the third circulator; and
wherein the second polarization controller being further connected to the second transmitter comprises:
the second polarization controller being further connected to the second transmitter through the third circulator.
16 . The second optical transmission apparatus according to claim 8 , wherein:
the first optical transmission apparatus is on an active antenna unit (AAU) side, and the second optical transmission apparatus is on a baseband unit (BBU) side; or
the first optical transmission apparatus is on a BBU side, and the second optical transmission apparatus is on an AAU side.
17 . A method, applied to a first optical transmission apparatus, the first optical transmission apparatus comprising a first circulator and a first receiver, and the method comprises:
receiving, by the first circulator, a second unmodulated optical signal from a second optical transmission apparatus; and
receiving, by the first receiver, a second modulated optical signal from the second optical transmission apparatus, and receiving the second unmodulated optical signal from the first circulator, wherein the second modulated optical signal is obtained by modulating a first unmodulated optical signal, the second unmodulated optical signal is used to perform coherence detection on the second modulated optical signal, the first unmodulated optical signal and the second unmodulated optical signal are obtained by separating a third unmodulated optical signal, and the third unmodulated optical signal is provided by the first optical transmission apparatus to the second optical transmission apparatus.
18 . The method according to claim 17 , wherein receiving, by the first circulator, the second unmodulated optical signal from the second optical transmission apparatus comprises:
receiving, by the first circulator, the second unmodulated optical signal from a second circulator, wherein the first circulator is further connected to the second circulator, and the second optical transmission apparatus comprises the second circulator.
19 . The method according to claim 17 , further comprising:
controlling, by a first polarization controller, polarization of the second unmodulated optical signal, wherein the first optical transmission apparatus further comprises the first polarization controller, and the first polarization controller is connected to the first circulator.
20 . The method according to claim 19 , wherein that the second unmodulated optical signal is used to perform coherence detection on the second modulated optical signal comprises: the second unmodulated optical signal on which polarization control is performed is used to perform coherence detection on the second modulated optical signal.