Reconfigurable optical add drop multiplexer core device, procedure and system using such device, optical light distributor, and coupling-ratio assigning procedure
View Patent ↗A reconfigurable optical add drop multiplexer core device includes a light distributor, a light combiner, and first and second sets of add and drop ports. The light distributor is configured to receive an optical signal along a primary input of the reconfigurable optical add drop multiplexer core device and to distribute the received optical signal along a plurality of subtending outputs. The light combiner is configured to receive optical signals along a plurality of subtending inputs, to combine the received optical signals into a combined signal, and to output the combined signal. The add and drop ports in the first set function as add and drop ports, respectively, and the add and drop ports in the second set function as both add and drop ports, respectively, and as express ports connectable to another reconfigurable optical add drop multiplexer core device.
1. A dense wavelength division multiplexing optical add/drop optical node comprising:
a first set of optical couplers;
a second set of optical couplers; and
a third set of optical couplers, an output of the first set of optical couplers and at least part of an output of the second set of optical couplers being input into the third set of optical couplers, coupling ratios for the first set of optical couplers being substantially equal, coupling ratios for the second set of optical couplers being such that a power level of an optical wavelength output therefrom is a minimum required power for optical wavelengths dropped from a first reconfigurable optical add drop multiplexer core device, and coupling ratios for the third set of optical couplers maximizing a power level of an optical wavelength exiting the third set of optical couplers.
2. The node set forth in claim 1 , the second set of optical couplers including a set of 1-to-2, optical-power-divider-type light distributors within a light distributor device configured to select any of the following operations: directing an entire optical power of the wavelength only to an express output thereof; directing the entire optical power of the wavelength only to one of subtending outputs thereof; and directing a portion of the optical power of the wavelength to only one of the subtending outputs and a portion of the optical power of the wavelength to the express output.
3. The node set forth in claim 1 , the first set of optical couplers including an optical coupler that combines signals from add ports contained on a port expansion module.
4. The node set forth in claim 1 , the first set of optical couplers including a first coupler that combines all signals of add ports operable as express ports, and a second coupler which combines all signals of add ports that do not operate as express ports.
5. The node set forth in claim 1 , the third set of optical couplers residing on the first reconfigurable optical add drop multiplexer core device and processing (a) signals from add ports of the first reconfigurable optical add drop multiplexer core device, (b) a signal from an express output port of a second reconfigurable optical add drop multiplexer core device, and (c) a signal from an expansion output port of an expansion module attached to the first reconfigurable optical add drop multiplexer core device.
6. A procedure for assigning coupling ratios for first, second, and third sets of optical couplers within a dense wavelength division multiplexing optical add/drop node, an output of the first set of optical couplers and at least part of an output of the second set of optical couplers being input into the third set of optical couplers, the procedure comprising:
selecting coupling ratios for the first set of optical couplers to be equal among all inputs of each optical coupler in the first set;
selecting coupling ratios for the second set of optical couplers such that a power level of an optical wavelength output therefrom is a minimum required power for optical wavelengths dropped from a first reconfigurable optical add drop multiplexer core device;
selecting coupling ratios for the third set of optical couplers to maximize a power level of an optical wavelength exiting the third set of optical couplers;
wherein at least one of the selecting steps are computer implemented.
7. The procedure set forth in claim 6 wherein the second set of optical couplers includes a set of 1-to-2, optical-power-divider-type light distributors within a light distributor device, and the procedure further comprises the light distributor device performing at least one of:
directing an entire optical power of the wavelength only to an express output thereof;
directing the entire optical power of the wavelength only to one of subtending outputs thereof; and
directing a portion of the optical power of the wavelength to only one of the subtending outputs and a portion of the optical power of the wavelength to the express output.
8. The procedure set forth in claim 6 , further comprising combining signals from add ports contained on a port expansion module.
9. The procedure set forth in claim 6 , further comprising combining all signals of add ports operable as express ports, and combining all signals of add ports that do not operate as express ports.
10. The procedure set forth in claim 6 , further comprising processing (a) signals from add ports of the first reconfigurable optical add drop multiplexer core device, (b) a signal from an express output port of a second reconfigurable optical add drop multiplexer core device, and (c) a signal from an expansion output port of an expansion module attached to the first reconfigurable optical add drop multiplexer core device, wherein the third set of optical couplers resides on the first reconfigurable optical add drop multiplexer core device.
11. The procedure set forth in claim 6 , wherein the selecting of the coupling ratios for the third set of optical couplers is performed such that a difference between levels of input signals to at least a first one of the optical couplers of the third set of optical couplers is about 6.7 dB.
12. The procedure set forth in claim 6 , wherein at least one of the optical couplers of the third set of optical couplers is a 20/80% coupler.
13. The procedure set forth in claim 11 , wherein the selecting of the coupling ratios for the third set of optical couplers is performed such that a difference between levels of input signals to at least a second one of the optical couplers of the third set of optical couplers is about 1.6 dB.
14. The procedure set forth in claim 13 , wherein the second one of the optical couplers is a 40/60% coupler.
15. The procedure set forth in claim 14 , wherein the first one of the optical couplers of the third set of optical couplers is a 20/80% coupler.
16. The procedure set forth in claim 15 , wherein a third one of the optical couplers of the third set of optical couplers is a 35/65% coupler.
17. The procedure set forth in claim 16 , wherein each optical coupler of the third set of optical couplers is a 2×1 optical coupler.
18. The node set forth in claim 1 , wherein a first one of the optical couplers of the third set of optical couplers is a 20/80% coupler, a second one of the optical couplers of the third set of optical couplers is a 40/60% coupler, and a third one of the optical couplers of the third set of optical couplers is a 35/65% coupler.
19. The node set forth in claim 1 , wherein each optical coupler of the third set of optical couplers is a 2×1 optical coupler.
20. The node set forth in claim 1 , wherein a difference between levels of input signals to at least one of the optical couplers of the third set of optical couplers is about 6.7 dB.