30 results about "Bragg resonance" patented technology

The invention belongs to the field of sensing technology, in particular to a dual-parameter measuring device for hydrogen concentration and ambient temperature based on an inclined optical fiber grating. It includes a light source, a tilted fiber grating coated with a palladium-silver alloy film, a single-mode fiber and a spectrometer. The light source is connected to a tilted fiber grating coated with a palladium-silver alloy film through a single-mode optical fiber, and the other end of the grating is connected to a spectrometer through a single-mode optical fiber. When the device is in a hydrogen environment, the palladium-silver alloy film will absorb hydrogen in the environment, causing changes in the evanescent field of the optical fiber. Its evanescent wave resonates with the surface plasmon wave generated by the free electrons on the metal surface, resulting in a resonance peak. The hydrogen concentration can be measured by using the interval between the plasma resonance peak and the Bragg resonance peak. The Bragg resonance peaks of tilted fiber gratings are sensitive to temperature. Therefore, we can use the plasmon resonance peak and Bragg resonance peak of the tilted fiber grating to realize the dual-parameter measurement of hydrogen concentration and temperature.

Provided is an optical waveguide with an inscribed Bragg grating, where the Bragg grating is stable at high temperature, has low scattering loss and high reflectivity. Also provided is a method for inscribing a Bragg grating in an optical waveguide, the method comprising irradiating the optical waveguide with electromagnetic radiation from an ultrashort pulse duration laser of sufficient intensity to cause a permanent change in an index of refraction within a core of the optical waveguide, where the irradiating step is terminated prior to erasure of a Bragg resonance, and heating the optical waveguide to a temperature and for a duration sufficient to substantially remove a non-permanent grating formed in the optical waveguide by the irradiating step.

The invention belongs to the laser technology field and especially relates to an all-silicon distributed feedback laser. A resonant cavity of the laser is formed through directly imprinting a Bragg grating on a nano-crystalline film. Simultaneously, the nano-crystalline film provides an optical gain so that the distributed feedback laser is formed. The nano-crystalline film is formed through carrying out heat annealing conversion on photoresist HSQ, and then high pressure hydrogen passivation processing is performed so that the nano-crystalline film possesses a high optical gain equivalent to that of a conventional laser semiconductor material. The Bragg grating is manufactured through a nanometer imprinting technology and a grating period corresponds to a second-order Bragg resonance condition of a laser wavelength. Laser light possesses high diffraction efficiency along a direction vertical to a grating surface direction and vertical emitting of the laser light can be realized. The invention provides a on-chip laser of an all-silicon material. The laser structure is compact and cost is low. A disadvantage that a silicon-based laser based on a semiconductor gain material is not compatible with a traditional silicon technology is avoided.