A semiconductor laser comprising a single mode laser cavity having a stack of semiconducting layers defining a transversal p-n junction is provided. A plurality of electrodes are coupled to corresponding sections of the laser cavity along the longitudinal light propagation direction, each corresponding section defining one of an amplification section or a modulation section. One or more DC sources are coupled to the electrodes associated with the amplification sections to forward-bias the p-n junction above transparency, so as to provide gain in the associated amplification sections. One or more modulation signal sources are coupled to the electrodes associated with the modulation sections, and apply a modulation signal across the p-n junction below transparency, the modulation signal providing a modulation of an output optical frequency of the semiconductor laser. Each modulation section is operated in photovoltaic mode.
H01S 5/32 - Structure ou forme de la région active; Matériaux pour la région active comprenant des jonctions PN, p.ex. hétérostructures ou doubles hétérostructures
H01S 5/065 - Accrochage de modes; Suppression de modes; Sélection de modes
H01S 5/125 - Lasers à réflecteurs de Bragg répartis [lasers DBR]
2.
LIGHT PULSE GENERATOR IN A CROSS-POLARIZATION CONFIGURATION
A light pulse generator for generating ultrashort light pulses is provided. The light pulse generator is based on a linear cavity free of polarizing components and configured to generate ultrashort light pulses based on spectral broadening of light. Segments of polarization maintaining fibers define an optical fiber path bound by first and second FBGs. A cross-polarization configuration in the cavity allows to couple a slow polarization axis of the optical fiber segment hosting the first FBG optical fiber segment with a fast polarization axis of the optical fiber segment hosting the second FBG. The cross-polarization configuration takes advantage of the birefringence of FBGs in polarization maintaining optical fibers to ensure a systematic start-up in only one predetermined polarization axis, without the necessity to add a polarizer or other polarizing component in the cavity.
A light pulse generator for generating ultrashort light pulses is provided. The light pulse generator is based on a linear cavity free of polarizing components and configured to generate ultrashort light pulses based on spectral broadening of light. Segments of polarization maintaining fibers define an optical fiber path bound by first and second FBGs. A cross-polarization configuration in the cavity allows to couple a slow polarization axis of the optical fiber segment hosting the first FBG optical fiber segment with a fast polarization axis of the optical fiber segment hosting the second FBG. The cross-polarization configuration takes advantage of the birefringence of FBGs in polarization maintaining optical fibers to ensure a systematic start-up in only one predetermined polarization axis, without the necessity to add a polarizer or other polarizing component in the cavity.
H01S 3/00 - Lasers, c. à d. dispositifs utilisant l'émission stimulée de rayonnement électromagnétique dans la gamme de l’infrarouge, du visible ou de l’ultraviolet
A light pulse generator for generating ultrashort light pulses based on an optical path apt to induce a spectral broadening of light is provided. A pair of spectrally selective filters is disposed at opposite extremities of the optical path, each having a corresponding reflective spectral band. The reflective spectral bands substantially overlap, thereby defining an overlap spectral range. One or more gain region, pumped by one or more pump source, is positioned between the spectrally selective filters. A blocking filter is provided between the spectrally selective filters and is configured to remove light at wavelengths within a blocking spectral range from the optical path, the blocking spectral range including at least the overlap spectral range. A method for generating ultrashort light pulses and optical systems are also provided.
H01S 3/102 - Commande de l'intensité, de la fréquence, de la phase, de la polarisation ou de la direction du rayonnement, p.ex. commutation, ouverture de porte, modulation ou démodulation par commande du milieu actif, p.ex. par commande des procédés ou des appareils pour l'excitation
A method of manufacturing a Volume Bragg Grating (VBG) is provided, comprising providing a cylindrical bulk medium made of a transparent glass material and having a central axis along a longitudinal direction, and inscribing an interference pattern in the cylindrical bulk medium. The interference pattern has a plurality of grating fringe elements distributed along a line parallel to the central axis. The method further includes rotating the cylindrical bulk medium about the central axis during said inscribing, thereby azimuthally extending the grating fringes elements. There is further provided a VBG manufactured according to such a method, the use of such a VBG in a CPA system of cladding-pumped fiber laser.
A method of manufacturing a Volume Bragg Grating (VBG) is provided, comprising providing a cylindrical bulk medium made of a transparent glass material and having a central axis along a longitudinal direction, and inscribing an interference pattern in the cylindrical bulk medium. The interference pattern has a plurality of grating fringe elements distributed along a line parallel to the central axis. The method further includes rotating the cylindrical bulk medium about the central axis during said inscribing, thereby azimuthally extending the grating fringes elements. There is further provided a VBG manufactured according to such a method, the use of such a VBG in a CPA system of cladding-pumped fiber laser.
A method of manufacturing a Volume Bragg Grating (VBG) is provided, comprising providing a cylindrical bulk medium made of a transparent glass material and having a central axis along a longitudinal direction, and inscribing an interference pattern in the cylindrical bulk medium. The interference pattern has a plurality of grating fringe elements distributed along a line parallel to the central axis. The method further includes rotating the cylindrical bulk medium about the central axis during said inscribing, thereby azimuthally extending the grating fringes elements. There is further provided a VBG manufactured according to such a method, the use of such a VBG in a CPA system of cladding-pumped fiber laser.
G03H 1/04 - Procédés ou appareils pour produire des hologrammes
G03H 1/02 - Procédés ou appareils holographiques utilisant la lumière, les infrarouges ou les ultraviolets pour obtenir des hologrammes ou pour en obtenir une image; Leurs détails spécifiques - Détails
G02B 5/32 - Hologrammes utilisés comme éléments optiques
8.
Semiconductor lasers with improved frequency modulation response
A semiconductor laser comprising a single mode laser cavity having a stack of semiconducting layers defining a transversal p-n junction is provided. A plurality of electrodes are coupled to corresponding sections of the laser cavity along the longitudinal light propagation direction, each corresponding section defining one of an amplification section or a modulation section. One or more DC sources are coupled to the electrodes associated with the amplification sections to forward-bias the p-n junction above transparency, so as to provide gain in the associated amplification sections. One or more modulation signal sources are coupled to the electrodes associated with the modulation sections, and apply a modulation signal across the p-n junction below transparency, the modulation signal providing a modulation of an output optical frequency of the semiconductor laser. Each modulation section is operated in photovoltaic mode.
H01S 5/32 - Structure ou forme de la région active; Matériaux pour la région active comprenant des jonctions PN, p.ex. hétérostructures ou doubles hétérostructures
H01S 5/065 - Accrochage de modes; Suppression de modes; Sélection de modes
H01S 5/125 - Lasers à réflecteurs de Bragg répartis [lasers DBR]
9.
Photobleaching of fiber bragg gratings written through the fiber coating
A method and a system for providing a low absorption Bragg grating along a grating region of an optical fiber are presented. The Bragg grating is written along the grating region by multiphoton absorption of ultrafast light pulses impinged on this grating region through a polymer coating of the optical fiber. The Bragg grating is then photobleached by propagating a photobleaching light beam along the optical fiber. The photobleaching light beam has optical parameters selected to reduce defects in the grating region induced by the writing of the Bragg grating in a substantially non-thermal regime.
A method and a system for providing a low absorption Bragg grating along a grating region of an optical fiber are presented. The Bragg grating is written along the grating region by multiphoton absorption of ultrafast light pulses impinged on this grating region through a polymer coating of the optical fiber. The Bragg grating is then photobleached by propagating a photobleaching light beam along the optical fiber. The photobleaching light beam has optical parameters selected to reduce defects in the grating region induced by the writing of the Bragg grating in a substantially non-thermal regime.
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.
A semiconductor laser comprising a single mode laser cavity having a stack of semiconducting layers defining a transversal p-n junction is provided. A plurality of electrodes are coupled to corresponding sections of the laser cavity along the longitudinal light propagation direction, each corresponding section defining one of an amplification section or a modulation section. One or more DC sources are coupled to the electrodes associated with the amplification sections to forward-bias the p-n junction above transparency, so as to provide gain in the associated amplification sections. One or more modulation signal sources are coupled to the electrodes associated with the modulation sections, and apply a modulation signal across the p-n junction below transparency, the modulation signal providing a modulation of an output optical frequency of the semiconductor laser. Each modulation section is operated in photovoltaic mode.
H01S 5/32 - Structure ou forme de la région active; Matériaux pour la région active comprenant des jonctions PN, p.ex. hétérostructures ou doubles hétérostructures
A semiconductor laser comprising a single mode laser cavity having a stack of semiconducting layers defining a transversal p-n junction is provided. A plurality of electrodes are coupled to corresponding sections of the laser cavity along the longitudinal light propagation direction, each corresponding section defining one of an amplification section or a modulation section. One or more DC sources are coupled to the electrodes associated with the amplification sections to forward-bias the p-n junction above transparency, so as to provide gain in the associated amplification sections. One or more modulation signal sources are coupled to the electrodes associated with the modulation sections, and apply a modulation signal across the p-n junction below transparency, the modulation signal providing a modulation of an output optical frequency of the semiconductor laser. Each modulation section is operated in photovoltaic mode.
H01S 5/32 - Structure ou forme de la région active; Matériaux pour la région active comprenant des jonctions PN, p.ex. hétérostructures ou doubles hétérostructures
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.
An optical phase modulation device for modulating a phase of an input light signal at a modulation frequency is provided, which can be used in integrated photonics applications. The device can include an optical phase modulator, for example a thermo-optic phase shifter having an effective refractive index that depends linearly temperature, configured to impart a phase shift to the input light signal, the phase shift varying quadratically in response to an applied modulating electric drive signal. The device can also include a phase modulator driver configured to apply the electric drive signal to the optical phase modulator, the electric drive signal having a time-varying component oscillating at half the modulation frequency and no time-constant component, thereby imparting the phase shift, modulated at the modulation frequency, to the phase of the input light signal to produce a phase-modulated light signal. Optical phase modulation systems and methods are also disclosed.
G02F 1/03 - Dispositifs ou dispositions pour la commande de l'intensité, de la couleur, de la phase, de la polarisation ou de la direction de la lumière arrivant d'une source lumineuse indépendante, p.ex. commutation, ouverture de porte ou modulation; Optique non linéaire pour la commande de l'intensité, de la phase, de la polarisation ou de la couleur basés sur des céramiques ou des cristaux électro-optiques, p.ex. produisant un effet Pockels ou un effet Kerr
G02F 1/035 - Dispositifs ou dispositions pour la commande de l'intensité, de la couleur, de la phase, de la polarisation ou de la direction de la lumière arrivant d'une source lumineuse indépendante, p.ex. commutation, ouverture de porte ou modulation; Optique non linéaire pour la commande de l'intensité, de la phase, de la polarisation ou de la couleur basés sur des céramiques ou des cristaux électro-optiques, p.ex. produisant un effet Pockels ou un effet Kerr dans une structure de guide d'ondes optique
G02F 1/01 - Dispositifs ou dispositions pour la commande de l'intensité, de la couleur, de la phase, de la polarisation ou de la direction de la lumière arrivant d'une source lumineuse indépendante, p.ex. commutation, ouverture de porte ou modulation; Optique non linéaire pour la commande de l'intensité, de la phase, de la polarisation ou de la couleur
16.
Optical fiber filter of wideband deleterious light and uses thereof
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.
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.
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.
H01S 3/00 - Lasers, c. à d. dispositifs utilisant l'émission stimulée de rayonnement électromagnétique dans la gamme de l’infrarouge, du visible ou de l’ultraviolet
H01S 3/04 - Dispositions pour la gestion thermique
H01S 3/02 - Lasers, c. à d. dispositifs utilisant l'émission stimulée de rayonnement électromagnétique dans la gamme de l’infrarouge, du visible ou de l’ultraviolet - Détails de structure
A heat-dissipation package for use with an optical fiber includes a base, a cover, and a hollow sleeve. The base includes an upper surface, a lower surface, and a groove embedded in the upper surface, the groove having a generally U-shaped cross-sectional shape. The cover is positioned on the upper surface of the base. The sleeve includes a cylindrical inner surface and an outer surface with a first portion which has a generally U-shaped cross section and a second portion which has a generally planar cross section such that edges of the planar cross section contact an open end of the U-shaped cross section. The first portion of the outer surface of the sleeve is positioned in the groove and the second portion of the outer surface of the sleeve is in contact with the cover. The sleeve is configured to encapsulate a heat-generating section of the optical fiber.
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.
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 deleterious 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.
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 deleterious 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.
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 deleterious 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.
A post-assembly wavelength-tuning method for an optical filter provided along an optical fiber mounted under tension in a packaging assembly is provided. The packaging assembly includes at least one packaging component mechanically coupled to the optical fiber and optically accessible from outside of the packaging assembly. The method includes a step of measuring a post-assembly spectral response of the optical filter and determining therefrom a spectral deviation with respect to a target spectral response. The method also includes a step of forming one or more laser-welded zones on the packaging component so as to cause a permanent deformation thereof. The permanent deformation induces a modification in length of the optical fiber, thereby changing the post-assembly spectral response of the optical filter to compensate for the measured spectral deviation.
A Mach-Zehnder optica! modulator with a series push-pull traveling wave electrode uses a balanced coplanar stripline with lateral ground planes (G1,G2). Two signal electrodes (13A,13B) extend along the center of the optical modulator adjacent and parallel to the optical waveguides (15A,15B) in a series push-pull configuration. The ground planes (G1, G2) run parallel to the signal electrodes (13A,13B), but are spaced laterally outward from the signal electrodes (13A,13B).
G02F 1/01 - Dispositifs ou dispositions pour la commande de l'intensité, de la couleur, de la phase, de la polarisation ou de la direction de la lumière arrivant d'une source lumineuse indépendante, p.ex. commutation, ouverture de porte ou modulation; Optique non linéaire pour la commande de l'intensité, de la phase, de la polarisation ou de la couleur
26.
ELECTRICAL WAVEGUIDE TRANSMISSION DEVICE FOR USE WITH A MACH-ZEHNDER OPTICAL MODULATOR
An electrical waveguide transmission device (15) accepts a differential electrical input signal (e.g., S+ and S-) propagating along two separate signal conductors (1,2) with grounded electrical return paths, and outputs the differential input signal to a series push-pull traveling wave electrode Mach-Zehnder optical modulator (10) over a pair of output conductors (8A.8B) that act as a return path for each other and provide a desired characteristic impedance matching that of the Mach-Zehnder optical modulator.
G02F 1/035 - Dispositifs ou dispositions pour la commande de l'intensité, de la couleur, de la phase, de la polarisation ou de la direction de la lumière arrivant d'une source lumineuse indépendante, p.ex. commutation, ouverture de porte ou modulation; Optique non linéaire pour la commande de l'intensité, de la phase, de la polarisation ou de la couleur basés sur des céramiques ou des cristaux électro-optiques, p.ex. produisant un effet Pockels ou un effet Kerr dans une structure de guide d'ondes optique
G02B 26/00 - Dispositifs ou dispositions optiques pour la commande de la lumière utilisant des éléments optiques mobiles ou déformables
27.
Low white frequency noise tunable semiconductor laser source
A low white frequency noise tunable semiconductor laser source is presented. The laser source includes a single-mode semiconductor laser assembly which generates a laser beam having a tunable frequency over a spectral range of interest. An optical filter is provided in the path of the laser beam. The optical filter has multiple spectral features distributed over the entire spectral range of interest. Each spectral feature has a narrow spectral range. A locking mechanism is further provided and is controllable for locking a spectral alignment between the frequency of the laser beam and any selected one of the spectral features of the optical filter.
H01S 3/10 - Commande de l'intensité, de la fréquence, de la phase, de la polarisation ou de la direction du rayonnement, p.ex. commutation, ouverture de porte, modulation ou démodulation
28.
Assembly for applying a temperature gradient to a refractive index grating and chromatic dispersion compensator
A power efficient assembly is provided for applying a temperature gradient to a Fiber Bragg grating. The assembly includes inner and outer enclosures, the outer enclosure defining an insulation chamber around the inner enclosure. The respective ends of the inner and outer enclosures are in thermal contact. A heat exchange system, such as coiled resistive wires or thermo-electric coolers, applies different temperatures to the opposite ends of the outer enclosure.
A colorless tunable dispersion compensator for compensating for chromatic dispersion in a multi-channel light signal is provided. The compensator includes a multi-channel Bragg grating extending along a waveguide. Dispersion tuning means, such as a temperature gradient inducing device, are provided for tuning the dispersion characteristics of the wavelength channels. Wavelength shifting means are also provided for uniformly shifting the central wavelengths of all channels independently of their dispersion characteristics. A uniform temperature inducing or strain applying assembly can be used for this purpose.
A method for manufacturing a complex multi-channel optical grating using a phase mask is presented. A plurality of sub-gratings is designed, each having an individual spectral response designed to produce one of the channels of the multi-channel grating. The target profile of the grating is determined based on the combination of the index profiles of the individual sub-gratings, the target index profile defining a target spectral response of the multi-channel grating. A modified index profile having a smooth apodization profile but providing the same spectral response as the target index profile, at least within a spectral region of interest, is determined and encoded into the phase mask. The phase mask is then used to photoinduce the grating in a photosensitive medium.
A narrow linewidth semiconductor laser device has a semiconductor laser and a low noise current source operatively connected to the laser with the current source being adapted to prevent degradation of the laser's frequency noise spectrum. An optical frequency discriminator provides an error signal representative of the laser's optical frequency and a control circuit has a feedback network that provides a frequency feedback signal that is adapted to the frequency noise spectrum of the frequency discriminator and to the laser's frequency noise spectrum and tuning response. The control circuit also has a sequencer to automatically enable frequency locking of the laser on the frequency reference of the optical frequency discriminator. An enclosure encloses the frequency discriminator to isolate the frequency discriminator from external perturbations. The device provides an improved sub-kHz linewidth and a high coherence while being compact, lightweight and highly reliable, as well as being automatically operated.
H01S 3/00 - Lasers, c. à d. dispositifs utilisant l'émission stimulée de rayonnement électromagnétique dans la gamme de l’infrarouge, du visible ou de l’ultraviolet
32.
Methods for the alignment and calibration of the spectral responses of optical filters
A method for aligning the spectral responses of two comb-like optical filters is provided. This method does not necessitate the use of spectrally-resolved equipment, as it uses the optical power correlation profile of a broadband light signal representative of the combined spectral responses of the two filters. In one embodiment, the power correlation profile is compared to a pre-stored profile. A tuning method for tuning two filters using this alignment method is also provided. The two filters are first relaxed to an unstretched position, and the second filter is stretched and aligned with the first. The first filter is also stretched and aligned with the other. Both filters are then stretched at a calibrated value.
brevets
