Chirp-managed, electroabsorption-modulated laser
View Patent ↗An optical transmitter comprising: an optical source modulated with an input digital data signal so as to generate a first, frequency-modulated digital signal; and an amplitude modulator, modulated with the logical inverse of the input digital data signal, for receiving the first, frequency-modulated signal and generating a second, amplitude-modulated and frequency-modulated digital signal; wherein the optical source and the amplitude modulator are each configured so as to produce positive transient chirp. A method for transmitting a signal, the method comprising: generating a first, frequency-modulated digital signal by modulating an optical source with an input digital data signal; and providing a second, amplitude-modulated and frequency-modulated digital signal by passing the first, frequency-modulated digital signal through an amplitude modulator while modulating the amplitude modulator with the logical inverse of the input digital data signal; wherein the optical source and the amplitude modulator are each configured so as to produce positive transient chirp.
1. An optical transmitter comprising:
an optical source modulated with an input digital data signal so as to generate a first, frequency-modulated digital signal; and
an amplitude modulator, modulated with the logical inverse of the input digital data signal, for receiving the first, frequency-modulated signal and generating a second, amplitude-modulated and frequency-modulated digital signal;
wherein the optical source and the amplitude modulator are each configured so as to produce positive transient chirp.
2. An optical transmitter according to claim 1 wherein the optical source is modulated by the input digital data signal such that, in the second, amplitude-modulated and frequency-modulated digital signal, the phase difference between two 1 bits separated by an odd number of 0 bits is an odd integer multiple of π.
3. An optical transmitter according to claim 1 wherein the optical source is modulated by the input digital data signal such that the adiabatic frequency excursion of the second, amplitude-modulated and frequency-modulated digital signal is between about 25% and about 75% of the bit rate frequency of the input digital data signal.
4. An optical transmitter according to claim 1 wherein the optical source is a semiconductor laser and the amplitude modulator is an electroabsorption modulator.
5. An optical transmitter according to claim 4 wherein the bias to the electroabsorption modulator is adjusted so as to generate positive transient chirp.
6. An optical transmitter according to claim 4 wherein the semiconductor laser is a distributed feedback (DFB) laser.
7. An optical transmitter according to claim 6 wherein the DFB laser and EA modulator are integrated on the same chip.
8. An optical transmitter according to claim 4 wherein the semiconductor laser is a distributed Bragg reflector laser.
9. An optical transmitter according to claim 1 wherein the optical source comprises one from the group consisting of: (i) y branch sampled grating lasers, (ii) sampled grating DBR lasers, (iii) external cavity lasers, and (iv) ring resonator external cavity lasers.
10. A method for transmitting a signal, the method comprising:
generating a first, frequency-modulated digital signal by modulating an optical source with an input digital data signal; and
providing a second, amplitude-modulated and frequency-modulated digital signal by passing the first, frequency-modulated digital signal through an amplitude modulator while modulating the amplitude modulator with the logical inverse of the input digital data signal;
wherein the optical source and the amplitude modulator are each configured so as to produce positive transient chirp.
11. A method according to claim 10 wherein the optical source is modulated by the input digital data signal such that, in the second, amplitude-modulated and frequency-modulated digital signal, the phase difference between two 1 bits separated by an odd number of 0 bits is an odd integer multiple of π.
12. A method according to claim 10 wherein the optical source is modulated by the input digital data signal such that the adiabatic frequency excursion of the second, amplitude-modulated and frequency-modulated digital signal is between about 25% and about 75% of the bit rate frequency of the input digital data signal.
13. A method according to claim 10 wherein the optical source is a semiconductor laser and the amplitude modulator is an electroabsorption modulator.
14. A method according to claim 13 wherein the bias to the electroabsorption modulator is adjusted so as to generate positive transient chirp.
15. A method according to claim 13 wherein the semiconductor laser is a distributed feedback (DFB) laser.
16. A method according to claim 15 wherein the DFB laser and EA modulator are integrated on the same chip.
17. A method according to claim 15 wherein the semiconductor laser is a distributed Bragg reflector laser.
18. A method according to claim 10 wherein the optical source comprises one from the group consisting of: (i) y branch sampled grating lasers, (ii) sampled grating DBR lasers, (iii) external cavity lasers, and (iv) ring resonator external cavity lasers.