Broadband 2×2 optical splitter

1. An optical device, comprising

a crossover component comprising a first 2×2 splitter, the first 2×2 splitter comprising a first input port, a second input port, a first output port, and a second output port;

a non-quadrature component comprises a second 2×2 splitter, the second 2×2 splitter comprising a first input port, a second input port, a first output port, and a second output port;

a first optical waveguide having a first optical path length, a first end that is optically coupled to the first output port or first input port of the crossover component, and a second end that is optically coupled to the first input port or first output port of the non-quadrature component; and

a second optical waveguide having a second optical path length that is different from the first optical path length, a first end that is optically coupled to the second output port or second input port of the crossover component, and a second end that is optically coupled to the second input port or the second output port of the non-quadrature component,

the optical device having a power splitting tolerance of ±1-dB or less over an ultra-broad wavelength range of about 1.25μ to about 1.65μ.

2. The optical device of claim 1 , wherein the non-quadrature component being configured to provide a 0 dB splitting ratio for light of at least one polarization and one wavelength, λ 0 , and configured to provide a splitting ratio that is less than 1 dB through a first continuous range of wavelengths that includes λ 0 .

3. The optical device of claim 1 , wherein at least one of the crossover component and the non-quadrature component comprises a Mach-Zehnder interferometer.

4. The optical device of claim 1 , wherein at least one of the crossover component and the non-quadrature component comprises an asymmetric coupler.

5. The optical device of claim 1 , wherein at least one of the crossover component and the non-quadrature component comprises a star coupler.

6. The optical device of claim 1 , wherein at least one of the crossover component and the non-quadrature component comprises a multi-mode interference coupler.

7. The optical device of claim 1 , wherein the difference between the first optical path length and the second optical path length provides a splitting ratio that is less than 1 dB over a first continuous range of wavelengths.

8. The optical device of claim 7 , wherein the difference between the first optical path length and the second optical path length provides a splitting ratio that is less than 1 dB over a second continuous range of wavelengths; the second continuous range of wavelengths being broader than the first continuous range of wavelengths.

9. The optical device of claim 1 , wherein at least one of the crossover component and the non-quadrature component comprises a symmetrical directional coupler having a coupling parameter that varies by more than a factor of two over said second continuous range of wavelengths.

10. The optical device of claim 1 , wherein a difference between the second optical path length and the first optical path length is about equal to a value that is within a target range of wavelengths.

11. The optical device of claim 1 , wherein the crossover component being configured to provide a splitting ratio greater than 16 dB for light of at least one polarization at wavelength λ 0 .

12. A PLC comprising the optical device of claim 1 .

13. An optical device comprising a primary four-port optical mixer capable of distributing optical power presented at either of two input ports to specified ratios in two output ports, the four-port mixer comprising a first component being a four port mixer having a power-distribution ratio at or about a specific wavelength λ 0 ; a second component being a four-port mixer having a power distribution ratio of dB-magnitude greater than 16-dB near wavelength λ 0 ; a first interconnecting waveguide connecting a first port on the first component to a first port on the second component; and a second interconnecting waveguide having a different length than the first interconnecting waveguide connecting a complementary second port on the first component to a complementary second port on the second component; wherein a power-splitting ratio of the primary mixer exhibits no more than ±1-dB variation over a 20% fractional range of optical wavelengths encompassing λ 0 .

14. The optical device of claim 13 , wherein a power-division ratio of the second component varies non-monotonically across the fractional range of optical wavelengths.

15. The optical device of claim 13 , wherein the first component is a symmetric directional coupler.

16. The optical device of claim 13 , wherein the second component comprises a Mach-Zehnder interferometer having an optical path length difference greater than about a shortest wavelength in the fractional range of optical wavelengths.

17. The optical device of claim 13 , wherein a path difference of the second interconnecting waveguide compared to a path difference of the first interconnecting waveguide is greater in magnitude than about a shortest wavelength in the wavelength range.

18. The optical device of claim 13 , wherein the second subcomponent comprises an asymmetric coupler.

19. The optical device of claim 13 having an even splitting ratio over a wavelength range of about 100 nm or more.

20. A PLC comprising the optical device of claim 13 .

21. An optical device, comprising

a crossover component comprising a first 2×2 splitter, the first 2×2 splitter comprising a first input port, a second input port, a first output port, and a second output port;

a non-quadrature component comprises a second 2×2 splitter, the second 2×2 splitter comprising a first input port, a second input port, a first output port, and a second output port;

a first optical waveguide having a first optical path length, a first end that is optically coupled to the first output port or first input port of the crossover component, and a second end that is optically coupled to the first input port or first output port of the non-quadrature component; and

a second optical waveguide having a second optical path length that is different from the first optical path length, a first end that is optically coupled to the second output port or second input port of the crossover component, and a second end that is optically coupled to the second input port or the second output port of the non-quadrature component,

wherein the non-quadrature component being configured to provide a 0 dB splitting ratio for light of at least one polarization and one wavelength, λ 0 , and configured to provide a splitting ratio that is less than 1 dB through a first continuous range of wavelengths that includes λ 0 ; the crossover component being configured to provide a splitting ratio greater than 16 dB for light of at least one polarization at wavelength λ 0 .

22. The optical device of claim 21 , wherein at least one of the crossover component and the non-quadrature component comprises a Mach-Zehnder interferometer.

23. The optical device of claim 21 , wherein at least one of the crossover component and the non-quadrature component comprises an asymmetric coupler.

24. The optical device of claim 21 , wherein at least one of the crossover component and the non-quadrature component comprises a star coupler.

25. The optical device of claim 21 , wherein at least one of the crossover component and the non-quadrature component comprises a multi-mode interference coupler.

26. The optical device of claim 21 , wherein the difference between the first optical path length and the second optical path length provides a splitting ratio that is less than 1 dB over a first continuous range of wavelengths.

27. The optical device of claim 26 , wherein the difference between the first optical path length and the second optical path length provides a splitting ratio that is less than 1 dB over a second continuous range of wavelengths; the second continuous range of wavelengths being broader than the first continuous range of wavelengths.

28. The optical device of claim 21 , wherein at least one of the crossover component and the non-quadrature component comprises a symmetrical directional coupler having a coupling parameter that varies by more than a factor of two over said second continuous range of wavelengths.

29. The optical device of claim 21 , wherein a difference between the second optical path length and the first optical path length is about equal to a value that is within a target range of wavelengths.