Sdl Inc.

Other

Jds Uniphase Corporation

Seastar Optics Inc.

Brian F Ventrudo

Grant Rogers

Peter G Berrang

Robert J Lang

Robert G Waarts

Mehrdad Ziari

John deAndrea

Colin J Mackechnie

Michael L Bortz

A fiber Bragg grating is used to stabilize the intensity and frequency fluctuations of a diode laser. The diode laser is connected with an opto-mechanical apparatus to the fiber which contains the grating. The grating is formed in the guided-mode region of the optical fiber. The wavelength of maximum grating reflectivity is selected to lie near the maximum of the diode laser gain bandwidth. The magnitude and bandwidth of the grating reflectivity stabilizes the diode laser output without appreciably reducing the optical output power from the end of the fiber. The bandwidth of the optical spectrum of the diode laser is selected depending on the distance of the grating from the diode laser.

Fiber grating stabilized diode laser

Apparatus is provided for an improved stabilized laser source comprising a laser source having a light beam output and an electrical input. An optical waveguide, such as an optical fiber, having an input end is optically coupled to the laser source to receive the light beam. A reflector in the optical fiber, such as a fiber grating, reflects a portion of the light beam output back into the laser source. The reflector is provided at a distance from the laser source permitting the laser source to switch between states of coherence and coherence collapse of operation. The electrical input of a drive signal for the laser source includes a modulated signal with variations in amplitude to the electrical input to control the variation in switching between the states of coherence and coherence collapse of the laser source so that continuous laser operation remains kink-free. The optical waveguide provides the laser source light beam output to an optical gain medium having an excited state of operation of duration equal to a relaxation time wherein intervals between the variations of drive current amplitude modulation are less than the relaxation time of the excited state of the optical gain medium.

Apparatus for providing a stabilized laser source

Apparatus for providing a laser source optically coupled to an optical waveguide, such as an optical fiber, having a reflective grating positioned from the output facet of the laser source a distance equal to or greater than the coherence length of the laser source providing a portion of reflective feedback into the laser source optical cavity to maintain wavelength operation of the laser source in spite of changes in the laser operating temperature or drive current based upon coherence collapse in the laser operation. In cases where the fiber grating is positioned in the fiber within the coherence length of the laser source, intermittent coherence collapse, as opposed to continuous coherence collapse, is unavoidable. In cases where such a laser source is a pumping source for a solid state gain medium, such as an optical amplifier or laser having an active gain element, e.g., an Er doped amplifier, undesirable perturbations in the laser source output are present which have a deleterious effect on the operation of the solid state gain medium. The effect of these undesirable perturbations are substantially removed by a small, continuous variation or dither in the driving current of the laser source having a rate of variation that exceeds the active gain element excited state lifetime thereby controlling the switching of the laser source operation between states of coherency and coherence collapse. As a result, the effects of laser source perturbations are avoided so as not to have an effect on the operation of the coupled solid state gain medium so that its gain stability is improved. Various embodiments of dither circuits are disclosed. In addition, polarization-maintaining behavior is induced in optical waveguides to further improve laser source stability.

Stabilization of laser sources with closely-coupled optical reflectors using an internal dither circuit

Apparatus is provided for an improved stabilized laser source comprising a laser source having a light beam output and an electrical input. An optical waveguide, such as an optical fiber, having an input end is optically coupled to the laser source to receive the light beam. A reflector in the optical fiber, such as fiber grating, reflects a portion of the light beam output back into the laser source. The reflector is provided at a distance from the laser source permitting the laser source to switch between states of coherence and coherence collapse of operation. The electrical input of a drive signal for the laser source includes a modulated signal with variations in amplitude to the electrical input to control the variation in switching between the states of coherence and coherence collapse of the laser source so that continuous laser operation remains kink-free. The optical waveguide provides the laser source light beam output to an optical gain medium having an excited state of operation of duration equal to a relaxation time wherein intervals between the variations of drive current amplitude modulation are less than the relaxation time of the excited state of the optical gain medium.

Fibre-grating-stabilized diode laser

Apparatus for stabilizing multiple laser sources having distinguishable optical characteristics, e.g., in polarization field or operational wavelength, comprises a plurality of semiconductor laser sources having respective lasing cavities capable of lasing within a narrow bandwidth of wavelengths and providing spectral outputs at their respective laser exit facets having different optical characteristics from one another. The spectral output beams of the sources may be coupled to respective optical fibers and the beams combined via a beam combiner, e.g., a polarizing beam combiner or a WDM combiner. The beam combiner combines the beam outputs forming a single beam which is launched into an output optical fiber. At least one feedback fiber grating is provided in at least one of the optical fibers with the number thereof depending upon distinguishable optical characteristics of the multiple laser sources. In the case of distinguishable optical characteristics in the form of polarization field, one grating is required and in the case of distinguishable optical characteristics in the form of operational wavelength, multiple gratings are necessary equal to the number of laser sources. The fiber grating or gratings have a reflectivity band for reflecting back a small portion of selected wavelengths of the single beam which are within the gain bandwidth of the laser sources while the remaining portion of the single beam transmitted through the grating or gratings to a final output. The grating or gratings have a reflectivity level approximately equal to or less than the reflectivity level of the laser source exit facets. The grating or gratings are positioned in the optical fiber or fibers to have an optical separation from the laser sources to cause the laser sources to operate in multiple longitudinal modes broadening the spectral output of the laser sources by several orders of magnitude.

Apparatus for stabilizing multiple laser sources and their application

A fibre Bragg grating is used to stabilize the intensity and frequency fluctuations of a diode laser. The diode laser is connected with an opto-mechanical apparatus to the fibre which contains the grating. The grating is formed in the guided-mode region of the optical fibre. The wavelength of maximum grating reflectivity is selected to lie near the maximum of the diode laser gain bandwidth. The magnitude and bandwidth of the grating reflectivity stabilizes the diode laser output without appreciably reducing the optical output power from the end of the fibre. The bandwidth of the optical spectrum of the diode laser is selected depending on the distance of the grating from the diode laser.

Apparatus for generating laser light having a wavelength in the range of about 1012 to 1022 nm comprising a double clad optical fiber having a core doped with triply ionised ytterbium ions, a source of laser light emitting at a wavelength of about 800 to 1070 nm and coupled to launch the fight into the fiber, and fiber Bragg gratings written into the core region of the optical fiber so as to provide optical discrimination of the emission centered in the range of about 1012 to 1022 nm.

Optical fibre laser pump source for fibre amplifiers

A fibre Bragg grating is used to stabilize the intensity and frequency fluctuations of a diode laser. The diode laser is connected with an opto-mechanical apparatus to the fibre which contains the grating. A polarization maintaining fibre is used. The grating is formed in the guided-mode region of the optical fibre using photorefractive techniques. The wavelength of maximum grating reflectivity is selected to lie near the maximum of the diode laser gain bandwidth. The magnitude and bandwidth of the grating reflectivity is sufficient to stabilize the diode laser output without appreciably reducing the optical output power from the end of the fibre. The bandwidth of the optical spectrum of the diode laser is increased or decreased relative to the solitary diode laser operating characteristics depending on the distance of the grating from the diode laser.

Apparatus for generating a stabilized laser source

A fibre Bragg grating is used to stabilize the intensity and frequency fluctuations of two diode lasers simultaneously. The polarized optical output from the diode lasers is collimated and directed through a beam combiner device which combines the separate beams into a single beam, thus summing the optical power. The combined beam is directed into an optical fibre containing a fibre Bragg grating which reflects a fraction of the light back into each diode laser to cause low-coherence, stable operation of each laser.

Multiple diode lasers stabilized with a fiber grating

A fibre Bragg grating is used to stabilize the intensity and frequency fluctuations of a diode laser. The diode laser is connected with an opto-mechanical apparatus to the fibre which contains the grating. The grating is formed in the guided-mode region of the optical fibre using photorefractive techniques. The wavelength of maximum grating reflectivity is selected to lie near the maximum of the diode laser gain bandwidth. The magnitude and bandwidth of the grating reflectivity is sufficient to stabilize the diode laser output without appreciably reducing the optical output power from the end of the fibre. The bandwidth of the optical spectrum of the diode laser is increased or decreased relative to the solitary diode laser operating characteristics depending on the distance of the grating from the diode laser.

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Victoria, Canada

Brian F Ventrudo