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.

Abstract: This specification discloses a light signal interleaver, which can separate a light signal into two light signals with a large interval in between. A birefringent plate is used as a light signal interleaver to separate all wavelengths in a light signal into an O-ray and an E-ray. Therefore, the invention can increase the total transmission capacity under the existent network structure.

Abstract: This specification discloses a light signal interleaver, which can separate a light signal into two light signals with a large interval in between. A birefringent plate is used as a light signal interleaver to separate all wavelengths in a light signal into an O-ray and an E-ray. Therefore, the invention can increase the total transmission capacity under the existent network structure.

Abstract: A method to reduce the FWHM of a slanted fiber grating. The slanted fiber grid is fabricated within a photosensitive fiber. The photosensitive fiber has a core for transmitting optical signals, an inner cladding around the core and an outer cladding around the inner cladding. The method to reduce the FWHM of the slanted fiber grating includes increasing the refractive index and/or diameter and/or lowering the photosensitivity of the inner cladding. In addition, a null core can be inserted into the center of the photosensitive fiber surrounded by an outer core. By increasing the diameter of the null core, the FWHM of the slant fiber grating can be reduced.

Abstract: The invention provides an optical amplifying system having a structure with two amplification levels to amplify received optical signals. The optical amplifying system includes a Michelson interferometer, a preamplifier, and a post amplifier. In the preamplifier and the post-amplifier, respectively have a light pumping source, a wavelength multiplexer, and an optical gain media. The Michelson interferometer includes an optical coupler and an optical grating set composed of a pair of optical gratings. The optical gratings are located different optical passes, and its central wavelength is equal to the intended wavelength. The optical grating can be formed on a piezoelectric substrate or an electrothermal substrate so that the central wavelength can be changed by applying stress or heat. The intended wavelength reflected by the Michelson interferometer can therefore be adjusted. The preamplifier and the post-amplifier are coupled together through the optical coupler of the Michelson interferometer.