Abstract: A bulk compressor for use in a chirped pulse amplification system (CPA) comprising a tunable pulse stretcher and an amplifier is provided. The bulk compressor includes a mounting block formed as a monolithic structure and made of solid material. The mounting block may define a plurality of mounting surfaces each forming a collar surrounding a light passage. Optical components are mounted on the mounting block in a fixed mutual spatial relationship, each optical component having a front face having a peripheral portion mounted in direct contact with the collar formed by a respective one of the mounting surfaces. The bulk compressor may be provided as a stand-alone component, a part of a stretcher-compressor pair or a full CPA system, and may be used in a method for amplifying input optical pulses.

Abstract: An optical fiber having a Bragg grating along a non-photosensitized grating region thereof and a pristine polymer coating around the grating region with the Bragg grating having been written through the polymer coating has a mechanical resistance that is greater than 20% of the mechanical resistance of an identical grating-free optical fiber.

Abstract: Methods and systems for writing a Bragg grating along a grating region of an optical fiber through a polymer coating of the optical fiber are provided. A light beam of ultrafast optical pulses is impinged on the grating region, the ultrafast optical pulses being characterized by writing wavelength at the grating region to which the polymer coating is substantially transparent The light beam is diffracted through a phase mask so as to form an interference pattern defining the Bragg grating at the grating region of the optical fiber. The light beam is also focussed such that the intensity of the optical pulses is below a damage threshold within the polymer coating, and above an FBG inscription threshold within the grating region of the fiber. Optical fiber having Bragg gratings and improved mechanical are also provided.

Abstract: Optical fiber filters and uses thereof are presented. In typical implementations, there is provided a FBG taking deleterious light out of a fiber core without reflecting it into the fiber core. It also allows the unhindered transmission of useful light at a wavelength outside of the spectral band covered by the deleterious light. The filter couples the incoming deleterious light to cladding modes propagating in the opposite direction without coupling the incoming useful light to core or cladding modes propagating in the opposite direction. The filter may for example be useful as a Raman or ASE filter in a laser cavity of other optical devices.

Abstract: Methods and systems for writing a Bragg grating along a grating region of an optical fiber through a polymer coating of the optical fiber are provided. A light beam of ultrafast optical pulses is impinged on the grating region, the ultrafast optical pulses being characterised by writing wavelength at the grating region to which the polymer coating is substantially transparent The light beam is diffracted through a phase mask so as to form an interference pattern defining the Bragg grating at the grating region of the optical fiber. The light beam is also focussed such that the intensity of the optical pulses is below a damage threshold within the polymer coating, and above an FBG inscription threshold within the grating region of the fiber. Optical fiber having Bragg gratings and improved mechanical are also provided.

Abstract: A method for manufacturing complex gratings masks having phase shifted regions and a holographic set-up for making the same are disclosed. The method, which can be easily automated, allows to produce arbitrary phase shift in holographically recorded gratings with high precision. In a preferred embodiment, the phase is controlled by a fringe locking system with a movable locking detector and a phase measuring device such as a camera for example, thereby allowing to provide a real-time phase locking and a real-time calibration of the set-up.

Abstract: A tunable phase mask assembly for use in photoinducing an optical wavelength filter in an optical waveguide. The phase mask assembly includes a phase mask having a length extending between two opposite longitudinal ends. The phase mask has grating corrugations projecting from its surface and distributed with a periodicity along its length. The periodicity of the phase mask is tuned by reversibly changing its length between the two longitudinal ends, such as by compressing or stretching the mask. In this manner, the interference pattern of a light beam passing through the phase mask is also tuned, which allows to control the characteristics of a wavelength filter photoinduced using this phase mask assembly.

Abstract: A system and a method for recording interference fringes in a photosensitive medium. Two light beams are guided along different light paths to impinge on a photosensitive medium, where they interfere to produce the interference fringes. One of the beam is reflected along its path on a delay mirror forming a fixed angle &phgr; with respect to the plane of the photosensitive medium. Both the photosensitive medium and delay mirror are translated with respect to the light paths of the two beams, thereby recording the interference fringes all along the medium. The angle &phgr; is chosen so that the interference pattern is fixed relative to the photosensitive medium along its length.

Abstract: A tunable phase mask assembly for use in photoinducing an optical wavelength filter in an optical waveguide. The phase mask assembly includes a phase mask having a length extending between two opposite longitudinal ends. The phase mask has grating corrugations projecting from its surface and distributed with a periodicity along its length. The periodicity of the phase mask is tuned by reversibly changing its length between the two longitudinal ends, such as by compressing or stretching the mask. In this manner, the interference pattern of a light beam passing through the phase mask is also tuned, which allows to control the characteristics of a wavelength filter photoinduced using this phase mask assembly.

Abstract: A system and a method for recording interference fringes in a photosensitive medium. Two light beams are guided along different light paths to impinge on a photosensitive medium, where they interfere to produce the interference fringes. One of the beam is reflected along its path on a delay mirror forming a fixed angle &phgr; with respect to the plane of the photosensitive medium. Both the photosensitive medium and delay mirror are translated with respect to the light paths of the two beams, thereby recording the interference fringes all along the medium. The angle &phgr; is chosen so that the interference pattern is fixed relative to the photosensitive medium along its length.

Abstract: A device and method for recording holographic gratings by the use of a single illuminating beam, two diffraction gratings, light detectors and a slit-scanning system. The beam illuminates two slits that then define two beams that are incident on the gratings. One diffracted order from one beam and one diffracted order from the other beam then interfere on a recording plane to produce sinusoidal variations of intensity. The interfering region may instantaneously be limited by a third slit. Also, another order of diffraction from one beam may be directed toward its own light detector and so is another order of diffraction from the other beam. These two detectors allow real time monitoring of the light intensity of each beam. By moving the slits in a direction parallel to the recording plane, an area larger than the slits' width can be exposed by the interfering pattern.