Method and device for converting an input light signal into an output light signal
A method and device for converting an input light signal into an output light signal, in an optical component is described. An input light signal, at a first wavelength, and a first light beam which may be at a second wavelength, are received at the component. The input light signal and the first light beam interfere in the component to form an interference pattern, which modifies a reflectivity spectrum of the component to increase the reflectivity of the component in a portion of the reflectivity spectrum. A second light beam, having a second wavelength corresponding with a wavelength within the portion of the reflectivity spectrum, is also received at the component and is then reflected from the component, in dependence upon the portion of the reflectivity spectrum, to generate the output light signal at the second wavelength. This enables conversion of light signals to signals at a different wavelength.
1. A device for converting an input light signal into an output light signal, the device comprising an optical component, said component having a refractive index having a spatial periodicity that determines a reflectivity spectrum of the component,
wherein the optical component is arranged to:
receive an input light signal having a first wavelength;
receive a first light beam, such that the first light signal and the first light beam interfere to form an interference pattern such that the reflectivity spectrum of the component is modified in dependence upon the interference pattern to increase the reflectivity of the component in a portion of the reflectivity spectrum;
receive a second light beam, the second light beam having a second wavelength corresponding with a wavelength within the portion of the reflectivity spectrum; and
reflect, from the optical component, in dependence upon the portion of the reflectivity spectrum, the second light beam to generate the output light signal, wherein the second light signal has the second wavelength.
2. A device according to claim 1 , wherein the optical component comprises at least two materials arranged alternately such that the refractive index of the component has a spatial periodicity resulting in the optical component having a reflectivity spectrum with at least one reflective peak.
3. A device according to claim 1 , wherein the optical component comprises one or more optical couplings arranged to couple light into and/or out of the component.
4. A device according to claim 1 , wherein the first light beam is received from a first light source and the second light beam is received from a second light source.
5. A device according to claim 4 , comprising the first and second sources.
6. A device according to claim 4 , wherein the first light source is different to the second light source.
7. A device according to claim 4 , wherein the first and second sources are tuneable.
8. A device according to claim 4 , wherein the second source is arranged to provide light at a polarisation substantially perpendicular to a polarisation of light provided by the first source.
9. A device according to claim 4 , wherein at least one of the first and second sources comprises a DFB laser.
10. A device according to claim 1 , wherein the optical component comprises a Bragg grating.
11. A device according to claim 10 , wherein at least a portion of the Bragg grating comprises a material having a refractive that has a non-linear response to electromagnetic radiation.
12. A device according to claim 1 , comprising an input data source.
13. An optical transistor comprising a device according to claim 1 .