Method for labeling optical fiber wavelength
The invention provides a method for labeling an optical fiber wavelength, including: deploying a spreading code on each of a transmit end and a receive end; transmitting a message code, and spreading the message code by using the spreading code of the transmit end; and performing envelope modulation on an optical signal by using the spread message code, transmitting the optical signal after the envelope modulation to the receive end, choosing, the spreading code of the receive end to despread the message code to obtain the original message code of the transmit end, and obtaining a corresponding wavelength according to the spreading code of the receive end. A spreading code having a correspondence with a wavelength is used to spread and despread a message code, and a modulation depth of an amplitude modulated signal may be greatly reduced to nearly prevent an envelope modulated signal from affecting a main signal.
1. A method for labeling an optical fiber wavelength by a transmit end, comprising:
deploying a spreading code on each of a transmit end and a receive end;
transmitting a message code, and spreading the message code by using the spreading code of the transmit end; and
performing envelope modulation on an optical signal by using the spread message code, transmitting the optical signal after the envelope modulation to the receive end, choosing, by the receive end, the spreading code of the receive end to despread the message code to obtain the original message code of the transmit end, and obtaining a corresponding wavelength according to the spreading code of the receive end,
wherein a correspondence is established between each of the spreading code of the transmit end and the spreading code of the receive end and a corresponding wavelength in a wavelength table.
2. The method for labeling an optical fiber wavelength by a transmit end according to claim 1 , wherein the spreading code is an orthogonal code or a pseudorandom sequence.
3. The method for labeling an optical fiber wavelength by a transmit end according to claim 1 , wherein the spreading the message code by using the spreading code of the transmit end comprises:
defining a code element of the message code as “0” and/or “1”;
selecting a spreading code x=(x 1 , x 2 , x 3 , . . . , x i , . . . , x n ), wherein x i ∈{−1, +1}, i=1, 2, 3, . . . n; and
when the message code is “0”, outputting the spreading code x i , and when the message code is “1”, negating the spreading code x i for output.
4. The method for labeling an optical fiber wavelength by a transmit end according to claim 1 , wherein the choosing, by the receive end, the spreading code of the receive end to despread the message code comprises:
choosing the spreading code of the receive end, and performing sliding despreading on the received spread message code by using the spreading code of the receive end, wherein when the spreading code of the receive end is the same as the spreading code of the transmit end, the original message code of the transmit end is accurately demodulated.
5. The method for labeling an optical fiber wavelength by a transmit end according to claim 4 , wherein the performing sliding despreading on the received spread message code by using the spreading code of the receive end comprises:
multiplying the spreading code of the receive end by the received spread message code bit by bit, calculating a nonnormalized cross-correlation coefficient between two bits “0” and “1”, and determining, according to the cross-correlation coefficient between the two bits, whether the spreading code of the receive end is the same as the spreading code of the transmit end.
6. The method for labeling an optical fiber wavelength by a transmit end according to claim 5 , wherein the calculating a nonnormalized cross-correlation coefficient between two bits “0” and “1”, and determining, according to the cross-correlation coefficient between the two bits, whether the spreading code of the receive end is the same as the spreading code of the transmit end comprises:
defining a threshold;
separately adding all code elements of the two bits “0” and “1” to calculate the cross-correlation coefficient between the two bits, and determining whether the cross-correlation coefficient is within a range of the threshold, wherein
if a determination result is no, the spreading code of the receive end is the same as the spreading code of the transmit end; or
if a determination result is yes, the spreading code of the receive end is different from the spreading code of the transmit end.
7. The method for labeling an optical fiber wavelength by a transmit end according to claim 6 , wherein after it is determined that the spreading code of the receive end is different from the spreading code of the transmit end, it continues to be determined whether a sliding distance of the spreading code of the receive end is equal to a bit width of the spreading code, and if a determination result is yes, the spreading code of the receive end is changed to continue to perform the step of sliding spreading, or if a determination result is no, the original spreading code of the receive end is used to continue to perform the step of sliding spreading.
8. A method for demodulating an optical fiber wavelength labeled by a transmit end by a receive end, comprising:
receiving, by a receive end for receiving an optical signal resource, an optical signal after envelope modulation from a transmit end;
removing an optical wave of the optical signal to obtain a spread message code of the transmit end; and
choosing a spreading code of the receive end, performing sliding despreading on the received spread message code by using the spreading code of the receive end, when the spreading code of the receive end is the same as a spreading code of the transmit end, obtaining the original message code of the transmit end, and obtaining a corresponding wavelength according to the spreading code of the receive end,
wherein a correspondence is established between each of the spreading code of the transmit end and the spreading code of the receive end and a corresponding wavelength in a wavelength table.
9. A method for labeling an optical fiber wavelength by a system, wherein the system comprises a transmit end and a receive end, and the method comprises:
performing, by the transmit end, steps of:
deploying a spreading code on each of the transmit end and the receive end;
transmitting a message code, and spreading the message code by using the spreading code of the transmit end; and
performing envelope modulation on an optical signal by using the spread message code, transmitting the optical signal after the envelope modulation to the receive end, choosing, by the receive end, the spreading code of the receive end to despread the message code to obtain the original message code of the transmit end, and obtaining a corresponding wavelength according to the spreading code of the receive end; and
performing, by the receive end, steps of:
receiving, by the receive end for receiving an optical signal resource, the optical signal after the envelope modulation of the transmit end;
removing an optical wave of the optical signal to obtain the spread message code of the transmit end; and
choosing the spreading code of the receive end, performing sliding despreading on the received spread message code by using the spreading code of the receive end, when the spreading code of the receive end is the same as the spreading code of the transmit end, obtaining the original message code of the transmit end, and obtaining a corresponding wavelength according to the spreading code of the receive end,
wherein a correspondence is established between each of the spreading code of the transmit end and the spreading code of the receive end and a corresponding wavelength in a wavelength table.