Abstract: A multi-channel imaging spectrometer, comprising an image acquiring unit, an optical detection element, a dispersion element and a lens module comprising a collimating lens module and a focusing lens module. The design of the lens module achieves elimination of primary aberrations such as coma and distortion through separating the collimating lens module and the focusing lens module, having identical structures with the collimating lens module, by a distance that is defined between a rear principle point of the collimating lens module and a front principle point of the focusing lens module and is twice of a front focal length of the focusing lens module. In addition, the lens module is also designed to exhibit linear dispersion for applied spectrum such that focus for each wavelength of the spectrum is linearly distributed on the imaging plane of the spectrometer so as to reduce the dispersion aberration.

Abstract: A multi-channel imaging spectrometer, comprising an image acquiring unit, an optical detection element, a dispersion element and a lens module comprising a collimating lens module and a focusing lens module. The design of the lens module achieves elimination of primary aberrations such as coma and distortion through separating the collimating lens module and the focusing lens module, having identical structures with the collimating lens module, by a distance that is defined between a rear principle point of the collimating lens module and a front principle point of the focusing lens module and is twice of a front focal length of the focusing lens module. In addition, the lens module is also designed to exhibit linear dispersion for applied spectrum such that focus for each wavelength of the spectrum is linearly distributed on the imaging plane of the spectrometer so as to reduce the dispersion aberration.

Abstract: The present invention provides a fiber Bragg Grating sequential writing method with real-time optical fiber position monitoring, characterized in that the relative phase between a fiber grating and a writing interference beam at each positioning point is determined by an interferometric side-diffraction method, and writing is sequentially performed. Accuracy in fabricating a long and complex fiber grating structure can be increased by decreasing or avoiding accumulative errors caused by long-term scan of monitoring optical fiber position, or by a means for fabricating a wanted reference fiber Bragg grating with similar settings.

Abstract: The present invention provides a fiber Bragg Grating sequential writing method with real-time optical fiber position monitoring, characterized in that the relative phase between a fiber grating and a writing interference beam at each positioning point is determined by an interferometric side-diffraction method, and writing is sequentially performed. Accuracy in fabricating a long and complex fiber grating structure can be increased by decreasing or avoiding accumulative errors caused by long-term scan of monitoring optical fiber position, or by a means for fabricating a wanted reference fiber Bragg grating with similar settings.

Abstract: The present invention provides a two-beam interference exposure system that can be simply adjusted by rotating only one mirror. By placing a half-wave plate in one of the interference arms and precisely scanning the relative fiber position, the present invention can expose true apodized fiber Bragg gratings in a single scan by simultaneously rotating the angle of the half-wave plate. By rotationally switching the fast and slow axes of the half-wave plate, the present invention can also expose n-phase-shifted fiber grating by the same system.

Abstract: The present invention provides a two-beam interference exposure system that can be simply adjusted by rotating only one mirror. By placing a half-wave plate in one of the interference arms and precisely scanning the relative fiber position, the present invention can expose true apodized fiber Bragg gratings in a single scan by simultaneously rotating the angle of the half-wave plate. By rotationally switching the fast and slow axes of the half-wave plate, the present invention can also expose n-phase-shifted fiber grating by the same system.

Abstract: The present invention provides a fabrication method of complex fiber grating structures that can be combined with prior fabrication methods including a phasemask or a two-beam interferometer. By using a rotatable half-wave plate with a polarization beam splitter in the optical path and precisely scanning the relative fiber position, we can expose true complex fiber gratings in a single scan by simultaneously rotating the angle of the half-wave plate.