Tunable Optical Supercontinuum Enhancement
The invention enables the spectral power within a narrow band of a broad spectrum of supercontinuum radiation to be significantly enhanced with simple components such as a long period grating in an optical fibre.
Supercontinuum radiation is quasi-white light produced by nonlinear processes in, for example, an optical fibre. The radiation is produced from a spectrally intense, monochromatic laser which undergoes a series of nonlinear interactions that vary the phase and dramatically broaden the spectrum. In extreme cases the spectrum becomes a "supercontinuum", spanning a number of octaves in frequency. Supercontinuum radiation is of interest in a number of areas including optical coherence tomography where a broadband, highly directional source of radiation is required.
This invention discloses the use of narrow spectral phase features introduced, for example, by a long period grating in the fibre, to create spectrum tailored enhancement of supercontinuum generation. The invention combines the advantages of spectral enhancement within a small wavelength region with broad tunability over a much larger range of wavelength than is possible with a fibre Bragg grating. Allowing the use of any spectral phase features permits a wide range of waveguide or other phase front modifications to be made beyond the currently restricted use of resonant dispersive features. The invention also enables dynamic tunability of the wavelength of the enhancement feature over a broad spectral range.
- Optical coherence tomography (OCT)
- optical frequency metrology
- fluorescence microscopy
- machine vision applications requiring highly directional light with well defined spectral characteristics, and others where high luminance well collimated "white" light is required.