Generation of at least 100 Gbit/s optical transmission
View Patent ↗A method includes generating at least two lightwave carriers from a lightwave source, the carriers having a wavelength spacing, creating an up-subchannel and a down-subchannel orthogonal to one another and spaced apart based on the fixed wavelength spacing from modulations of the lightwave carriers according to respective up-converted OFDM signals that are carrier suppressed, and combining one lightwave from the up-subchannel and one lightwave from the down-subchannel into an optical channel for transmission over an optical fiber.
1. A method comprising the steps of:
generating at least two lightwave carriers from a lightwave source, the carriers having fixed wavelength spacing;
creating an up-subchannel and a down-subchannel orthogonal to one another and spaced apart based on a wavelength spacing from modulations of the lightwave carriers according to respective up-converted OFDM signals that are carrier suppressed;
combining one lightwave from the up-subchannel and one lightwave from the down-subchannel into an optical channel for transmission over an optical fiber;
splitting the lightwave source into two orthogonal polarization signals to provide cascading of the step of creating an up-subchannel and a down-subchannel orthogonal to one another and spaced apart based on the wavelength spacing from modulations of the lightwave carriers according to respective up-converted OFDM signals that are carrier suppressed;
wherein said creating comprises each of the polarization signals being a distinct one of the lightwave source for generating a first set of two lightwave carriers and a second set of two lightwave carriers and the step of creating provides a first pair of the up-subchannel and down-subchannel corresponding to the first set of two lightwave carriers and a second pair of up-subchannel and down-subchannel corresponding to the second set of two lightwave carriers; and
wherein said combining comprises combining one lightwave from the first pair of up-subchannel, one lightwave from the down-subchannel from the first pair, one lightwave from the second pair of up-subchannel, one lightwave from the down-subchannel from the second pair into an optical channel for transmission over an optical fiber.
2. The method of claim 1 , wherein the wavelength spacing is 2f and the up-subchannel and the down-subchannel are spaced apart f.
3. The method of claim 1 , wherein the wavelength spacing is 2f and the up-subchannel and the down-subchannel are spaced apart 3f.
4. The method of claim 1 , wherein the OFDM signals are each at least 50 Gbit/s signals and the optical channel from combining the up-subchannel and down-subchannel is at least 100 Gbit/s.
5. The method of claim 1 , wherein the step of combining comprises optically filtering out the one lightwave from optical spectrums of the modulations of the lightwave carriers according to respective up-converted OFDM signals.
6. The method of claim 1 , wherein the up-converted OFDM signals are carrier suppressed by the up-converted OFDM signals driving an intensity external modulator that is biased at the null point generate carrier suppression.
7. The method of claim 1 , wherein the up-converted OFDM signals comprise the OFDM signals being upconverted by an electrical mixer to a frequency related to half the wavelength spacing.