Methods and systems for multi-level beacon tone modulation of an optical data signal

1. A method comprising:

receiving data;

modulating the data to generate a modulated data signal, wherein the modulated data signal comprises a first level modulated with a first beacon tone and a second level modulated with one or more of the first beacon tone or a second beacon tone, and wherein the second level is modulated in phase with the first level; and

transmitting an optical signal comprising the modulated data signal.

2. The method of claim 1 , wherein the first level is separated from the second level by a fixed direct current voltage bias.

3. The method of claim 1 , wherein transmitting the optical signal comprises transmitting the optical signal in free space.

4. The method of claim 1 , wherein receiving the data comprises receiving one or more of a data signal, a data stream, or a data file.

5. The method of claim 1 , further comprising applying pulse amplitude modulation to one or more of the data, the modulated data signal, or the optical signal.

6. The method of claim 1 , wherein a total power level of the optical signal remains constant while an amplitude of one or more of the first beacon tone or the second beacon tone varies.

7. The method of claim 1 , wherein a swing of the optical signal remains constant while an amplitude of one or more of the first beacon tone or the second beacon tone varies.

8. A device comprising:

a modulator configured to:

receive data; and

modulate the data to generate a modulated data signal, wherein the modulated data signal comprises a first level modulated with a first beacon tone and a second level modulated with one or more of the first beacon tone or a second beacon tone, and wherein the second level is modulated in phase with the first level; and

an optical terminal configured to transmit an optical signal comprising the modulated data signal.

9. The device of claim 8 , wherein the first level is separated from the second level by a fixed direct current voltage bias.

10. The device of claim 8 , wherein the optical terminal being configured to transmit the optical signal comprises the optical terminal being configured to transmit the optical signal in free space.

11. The device of claim 8 , wherein the data comprises one or more of a data signal, a data stream, or a data file.

12. The device of claim 8 , wherein the modulator is further configured to apply pulse amplitude modulation to one or more of the data, the modulated data signal, or the optical signal.

13. The device of claim 8 , wherein a total power level of the optical signal remains constant while an amplitude of one or more of the first beacon tone or the second beacon tone varies.

14. The device of claim 8 , wherein a swing of the optical signal remains constant while an amplitude of one or more of the first beacon tone or the second beacon tone varies.

15. A system comprising:

an optical transmitter configured to:

receive data;

modulate the data to generate a modulated data signal, wherein the modulated data signal comprises a first level modulated with a first beacon tone and a second level modulated with one or more of the first beacon tone or a second beacon tone, and

wherein the second level is modulated in phase with the first level; and

transmit an optical signal comprising the modulated data signal; and

an optical receiver configured to:

receive the optical signal, and

filter one or more of the first beacon tone or the second beacon tone from the optical signal.

16. The system of claim 15 , wherein the optical receiver is configured to filter one or more of the first beacon tone or the second beacon tone from the optical signal by using a high pass filter.

17. The system of claim 15 , wherein the data comprises one or more of a data signal, a data stream, or a data file.

18. The system of claim 15 , wherein the optical transmitter is further configured to apply pulse amplitude modulation to one or more of the data, the modulated data signal, or the optical signal.

19. The system of claim 15 , wherein a total power level of the optical signal remains constant while an amplitude of one or more of the first beacon tone or the second beacon tone varies.

20. The system of claim 15 , wherein a swing of the optical signal remains constant while an amplitude of one or more of the first beacon tone or the second beacon tone varies.