41results about How to "Large free spectral range" patented technology

An apparatus and method are disclosed for decreasing the spectral bandwidth of a semiconductor laser, such as a vertical cavity surface emitting laser.

The invention discloses a two-dimensional topological photonic crystal cavity, a design method thereof, and application in a laser. The two-dimensional topological photonic crystal cavity comprises aplurality of photonic crystal supercells that have a vortex-type structure change around the cavity center of the two-dimensional topological photonic crystal cavity, and the energy band of the plurality of photonic crystal supercells has a Dirac point at the equilibrium position where the vortex-type structure changes. The two-dimensional topological photonic crystal cavity, also known as a Diracvortex cavity, has the characteristics such as large mode field area, large free spectral range, narrow beam divergence angle, degeneracy of any mode and compatibility with a variety of substrate materials, and can be applied to surface emitting semiconductor lasers to ensure that the laser can still work stably in both single transverse mode and single longitudinal mode when outputting at largearea and high energy.

The invention discloses an internal and external double microring resonator structure comprising an N-Sub type substrate. A SiO2 buried layer is arranged on the top part of the N-Sub type substrate. An upper side straight waveguide and a lower side straight waveguide are respectively arranged at the two sides of the top part of the SiO2 buried layer. An external ring waveguide and an internal ring waveguide are arranged in the middle of the top part of the SiO2 buried layer. The internal and external double microring resonator structure has the advantages of flat harmonic peak and large free spectrum range so that the resonance characteristic of the microring resonator can be improved without increasing the chip area or the technology cost, and development of the microring resonator structure to the direction of high speed and low power consumption is facilitated.

The invention relates to a polarization-irrelevant tunable Fabry-Perot filter which is characterized by comprising two liquid crystal boxes and a drive circuit; the two liquid crystal boxes respectively comprises a first optic transparent material, a liquid crystal material and a second optic transparent material which are installed sequentially; the second optic transparent material of the first liquid crystal box and the first optic transparent material of the second liquid crystal box are installed together; the optical axes of liquid crystal materials in the two liquid crystal boxes are vertical to each other and are arranged in a Fabry-Perot cavity; and the drive circuit is connected with the two liquid crystal boxes and a turning function of the filter is realized by controlling effective refractive indexes of the liquid crystal materials. The polarization-irrelevant tunable Fabry-Perot filter is reasonable in design, stable and reliable in performance, low in cost, small in size, easy for installation and production, and the like, has the turning characteristic irrelevant to a polarization state of incident light, does not have a mechanical moving part, and can be widely applied to the fields of lasers, optical test, optical fiber communication, organisms, medical equipment, optical fiber sensor networks, and the like.

An apparatus and method are disclosed for decreasing the spectral bandwidth of a semiconductor laser, such as a vertical cavity surface emitting laser.

The invention discloses a liquid crystal tunable wave filter and a configuration method thereof. The wave filter comprises a plurality of stages of cascaded Leo configuration wave filter units, and each Leo configuration wave filter unit consists of polarizing sheets of both sides and birefraction optical elements in the middle, wherein parts of or all of the Leo configuration wave filter units are merged through two continuous cascades or three continuous cascades for forming a merged unit, the merging mode is an overlapped type or fan type merging mode, and the birefraction optical elements are liquid crystal tunable wave plates or fixed wave plates or the combination of the liquid crystal tunable wave plates and the fixed wave plates. The liquid crystal tunable wave filter of the invention has the advantages of high passing rate, narrow full width at half maximum, high shielding rate, adjustable light spectrum range, high stability, no need of mechanical rotation, real-time controllability and the like, and can be widely applied to various fields such as imaging, biology, medicine, materials, optics, photonics, astronomy and the like.

The invention discloses a waveguide raman scattering cavity based on a twice-coupling prism. The waveguide raman scattering cavity comprises a glass substrate, a glass gasket and a glass prism which are sequentially overlapped, wherein a sample chamber is formed between the glass substrate and the glass prism, the sample chamber is provided with a sample inlet channel and a sample outlet channel, a lower-layer metal membrane is deposited on the upper surface of the glass substrate, an upper-layer metal membrane is deposited on the lower surface of the glass prism, and the glass prism can meet the conditions that incident light from the lateral side of the glass prism is reflected by the lower surface of the glass prism, then fully reflected by the upper surface of the glass prism and then reflected by the lower surface of the glass prism to be emitted from the other lateral side of the glass prism. The waveguide raman scattering cavity of the structure can achieve low-transmittance narrow-band filtering and obtain a high-sensitivity raman spectrum without using band-stop filter plates.

The invention relates to the technical field of optical fiber sensing, in particular to a Fabry-Perot sensor based on a silicon core optical fiber and a preparation method thereof. The Fabry-Perot sensor based on the silicon core optical fiber comprises a common single mode optical fiber, an optical fiber fusion end face, the silicon core optical fiber and a polished end face, wherein an input optical fiber and the silicon core optical fiber are fused to form a fusion end face, the silicon core optical fiber consists of a silicon core optical fiber cladding and a silicon core optical fiber core, the polished end face is formed by grinding and polishing the end face of the silicon core optical fiber, and the fusion end face and the polished end face form two mirror faces of a silicon core optical fiber Fabry-Perot cavity. The Fabry-Perot sensor based on the silicon core optical fiber prepared by the invention has high temperature sensitivity, laser power sensitivity and response speed,and the Fabry-Perot sensor based on the silicon core optical fiber also has the advantages of simple structure, easiness in manufacturing, good repeatability and the like.

An etalon and a manufacturing method thereof relate to the optical field, in particular to the field of etalons. Ultra-thin film solid and hollow etalons are manufactured by binding plating with deepening optical cement and optical cement. After an optical medium with a certain thickness is directly plated on a reflecting film or a high reflecting film at the cavity part of the etalon, the solid etalon is formed by the optical cement and the deepening optical cement of another film layer in the cavity of the etalon or after a homogeneous dielectric film is placed in the non-central area of the film surface of the cavity of the etalon by adopting the shading or the photo etching method, the ultra-thin etalon with an air gap at the center is formed by the mutual optical cement and the deepening optical cement again. The invention discloses a novel etalon by adopting the technical proposal. The etalon has a small thickness, can achieve a plurality of um magnitudes, is bonded together by adopting the optical cement method and the deepening optical cement method, and can be manufactured more conveniently. Furthermore, the ultra-thin etalon has larger free spectral range and is suitable for laser mode selection and other aspects.

The invention relates to a single-mode continuous tunable optical filter which is mainly, technically characterized by comprising two transmission frequency Fabry-Perot tunable filters which are oppositely arranged back and forth, when the free spectral range of a first transmission frequency Fabry-Perot tunable filter is different from the intrinsic free spectral range of a second transmission frequency Fabry-Perot tunable filter at a certain interval, the transmission frequency tunable characteristic of the two transmission frequency Fabry-Perot tunable filters is utilized, so the tunable single-mode output is realized within a certain spectral range. The single-mode continuous tunable optical filter is reasonable in design, has the characteristics of no mechanical moving parts, stable and reliable performance, simple structure, low cost, small size, easiness for installation and production and the like, can meet the required small dimensions and reliable operation under extreme working environments, and can be widely applied in the fields of laser, optical test, optical fiber communication, biology, medical appliance, optical fiber sensor network and the like.

The invention belongs to the technical field of sensing, and provides an on-line dualbeam interference-type fiber refractive index sensor. The dualbeam interference-type fiber refractive index sensor comprises first single-mode fiber, light splitting fiber, offset-welded sensing single-mode fiber and reference single-mode fiber, light composition fiber and second single-mode fiber; while measuring, the sensing single-mode fiber is positioned in a to-be-checked substance; the wide spectrum light is input from the first single-mode fiber, then is coupled to the sensing single-mode fiber, and is subjected to propagation by a fiber core mode and a cladding mode and then mode transition, the fiber core mode is coupled to a cladding layer for continuous propagation, the partial energy of the cladding mode is coupled in the fiber core for continuous propagation, the light output by the reference single-mode fiber is subjected to light composition interference in the light composition fiber and is output through the second single-mode fiber, wavelength demodulation is carried out, and the refractive index change is obtained. Due to the light path compensation of the reference single-mode fiber, interference fringe drift distance is large, sensitivity is higher; the cooperation of the sensing single-mode fiber and the reference single-mode fiber have temperature compensating effect, so that the interference immunity and detection precision of the sensor are increased.

The invention discloses a continuously adjustable frequency interval V-shaped coupled cavity double-wavelength semiconductor laser. One end of a first active resonator cavity and one end of a second active resonator cavity are coupled in the shape of V to form a multi-mode coupled region. A cavity surface reflecting surface is arranged on the end face of the multi-mode coupled region. The other end of the first active resonator cavity and a first passive filter are connected in series through a deep etching groove to form an arm of the laser. The other end of the second active resonator cavity and a second passive filter are connected in series through a deep etching groove to form the other arm of the laser. Shallow etching grooves are arranged on the first active resonator cavity and the second active resonator cavity. The laser provided by the invention has the advantages of compact structure, simple production process, low cost and the like, and does not need an external reference light source.

The invention discloses a single-longitudinal-mode erbium-doped fiber laser based on a gourd-shaped auxiliary cavity, and belongs to the technical field of laser. The system comprises a 980nm semiconductor laser, a 980 / 1550nm wavelength division multiplexer, erbium-doped fibers A and B, an optical coupler, a fiber Bragg grating, a polarization controller, a polarization beam splitter, the gourd-shaped auxiliary cavity and isolators A, B and C. The 980nm semiconductor laser is used for pumping of the erbium-doped fiber A through the 980 / 1550nm wavelength division multiplexer to generate stimulated radiation light. Under the action of the isolator A and the isolator B, the stimulated radiation light is transmitted in the anticlockwise direction. Under the action of the Er-doped fiber B, thefiber Bragg grating, the polarization controller, the polarization beam splitter and the gourd-shaped auxiliary cavity, the stimulated radiation light is finally transmitted in the cavity in only onestable mode; and the stable transmission mode is outputted through the optical coupler and the isolator C. The fiber laser is novel in concept, is simple in structure, can solves a problem of multi-longitudinal-mode oscillation in an annular cavity Er-doped fiber laser, reduces the line width of the fiber laser, and has a wide application range.

The invention discloses a transient high resolution spectrometer based on an F-P etalon, relating to the high resolution light spectrum measurement field and the transient light spectrometry field. The high resolution spectrometer disclosed by the invention realizes the high resolution detection of single-pulse transient spectrum through utilizing standard self-angle-light splitting and serial connection of multiple F-P etalons. The invention can be applied in the high resolution spectrum measurement field including the Brillouin scattering, the Zeeman effect, the spin electronics, etc.

The invention belongs to the technical field of terahertz sub-wavelength structure sensing, and provides a terahertz waveguide sensing device based on a Fano resonance coupling resonant cavity and a preparation method thereof. The terahertz waveguide sensing device based on the Fano resonance coupling resonant cavity comprises a substrate and a waveguide sensing unit, the waveguide sensing unit is arranged on the substrate and comprises a waveguide, a rectangular resonant cavity and a metal wall, and the rectangular resonant cavity is directly connected to one side of the waveguide in the direction perpendicular to the waveguide. The metal wall is arranged in the waveguide medium at a set distance on one side of the rectangular resonant cavity, and the center of the metal wall is provided with an aperture; and the direction of the rectangular resonant cavity is kept parallel to the polarization direction of the electric field, and the input end of the waveguide is used for receiving terahertz waves, so that Fano resonance is generated when the terahertz waves meet resonance conditions in the transmission process. By adopting a metal-medium-metal waveguide coupling resonant cavity structure, the refractive index sensing application with sharp Fano resonance, high Q factor and high sensitivity is realized.

The invention discloses a linear chromatic dispersion combined prism beam splitting device which is formed by combining two prisms made of a special selected material and provided with coating films on the side faces in the mode of 'bottom surface adhesion and opposite coating film faces'. The linear chromatic dispersion combined prism beam splitting device is especially suitable for spectral analysis, spectrum detection and other relevant fields. Based on a control variable method and a differential equation thought, the non-linear chromatic dispersion of the second prism is utilized to compensate non-linear chromatic dispersion of the first prism so as to obtain the linear chromatic dispersion combined prism beam splitting device by controlling light propagation direction and the shapes of the prisms according to the chromatic dispersion characteristic of a first prism material. The linear chromatic dispersion combined prism beam splitting device overcomes the defect of chromatic dispersion non-linearity of the single prism and has the advantages of being wide in free spectral range, high in light energy utilization rate, good in universality, simple in structure, low in price and the like.

The invention discloses a multi-slit polarization imaging spectrometer based on Amici prism splitting. The multi-slit polarization imaging spectrometer consists of a prepositive teleobjective, polarizing multi-slits, a collimating lens, double Amici prisms, an imaging lens and a detector. An infinite target scene is imaged on a single image plane through the prepositive teleobjective by optical radiation, the single image plane is provided with the polarizing multi-slits, beams emit in parallel from the collimating lens for splitting by the double Amici prisms through the polarizing multi-slits, the split beams get through the imaging lens, and polarizing spectral information of the target scene is obtained by the detector. The double Amici prisms are composed of three dispersive prisms in type of symmetric prisms, and the polarizing multi-slits are of three-slit structure. The multi-slit polarization imaging spectrometer achieves a wider field range with the combination of the polarizing multi-slits and the double Amici prisms. A single exposure can directly obtains the three pieces of polarization information of the target scene, and septuple space information of the target scene can be achieved with push-scanning of the whole apparatus.

The invention discloses an on-chip light source modulation system which comprises a silicon substrate, a silicon dioxide buried oxide layer and a silicon nitride layer, the silicon nitride layer comprises a first waveguide, a second waveguide, a third waveguide and a fourth waveguide which are sequentially arranged, a micro-ring resonant cavity is arranged between the first waveguide and the second waveguide, the distance between the micro-ring resonant cavity and the first waveguide is a first set distance, the distance between the micro-ring resonant cavity and the second waveguide is a second set distance; a micro-ring filter is arranged between the second waveguide and the third waveguide, the distance between the micro-ring filter and the second waveguide is a third set distance, and the distance between the micro-ring filter and the third waveguide is a fourth set distance; a micro-ring modulator is arranged between the third waveguide and the fourth waveguide, the distance between the micro-ring modulator and the third waveguide is a fifth set distance, and the distance between the micro-ring modulator and the fourth waveguide is a sixth set distance. According to the system, the three silicon nitride micro-ring structures are used for processing an input light source, and an optical frequency comb with a wider free spectral range can be generated.

The invention discloses an optical fiber FP air pressure sensor with optical vernier effect and a preparation method thereof. The sensor comprises a single-mode optical fiber, a quartz capillary and a photonic crystal optical fiber. The two ends of the quartz capillary are respectively connected to the respective ends of the single-mode fiber and the photonic crystal fiber by fusion; the other end of the photonic crystal fiber is directly connected to the outside world, and its hole structure is convenient for the outside gas to enter the fiber optic FP sensor. In the cavity, the quartz capillary and the photonic crystal fiber form two Fabry-Perot resonant cavities with vernier effect. A commercial optical fiber fusion splicer is used for preparation, the discharge time and intensity of the electrodes are well controlled to cascade the two types of optical fibers and the optical fiber is cut using a precision cutting device, and the length of the optical fiber is strictly controlled to produce a vernier effect. The optical fiber FP air pressure sensor of the invention has the advantages of small volume, simple preparation, strong adaptability, high sensitivity and wide application prospect.

The invention discloses an air slot beam splitting Fabry-Perot resonant cavity coupling laser. A Fabry-Perot resonant cavity comprises an air slot, two waveguides and two high-reflectivity reflectors, wherein the air slot inclines to an active waveguide and can be filled with a medium; one waveguide and the active waveguide are coaxial and are respectively positioned at two sides of the air slot; angles between the two waveguides and the air slot are equal and positioned at the same side of the air slot and are coincide with the connecting port of the air slot; the high-reflectivity reflectors are respectively arranged on non-air slot connecting ports of the two waveguides; or tune electrodes cover the two waveguides and a phase matching electrode covers the active waveguide. Light is reflected and transmitted through the air slot for splitting beam. Two waveguides are additionally arranged to form the Fabry-Perot resonant cavity for selecting a die. The invention has the advantages of large free light spectrum range and low manufacture difficulty; and output wavelength of a laser can be largely tuned through regulating the optical length of the waveguides. The laser can operate in a single longitudinal mode.

The invention discloses an electrically tunable optical filter insensitive to the polarization state of incident light, which comprises a first Fabry-Perot interference cavity and a second Fabry-Perotinterference cavity which have the same principle and basic structure and are liquid crystal boxes driven by a power supply, wherein the first Fabry-Perot interference cavity comprises two spaced glass substrates, the two opposite surfaces of the two glass substrates are inner surfaces and are parallel to each other, the incident direction of light rays is perpendicular to the inner surfaces, andthe inner surfaces are sequentially plated with transparent electrodes, broadband high-reflectivity dielectric films and liquid crystal orientation films; the transparent electrodes on the glass substrates are respectively connected with two poles of an alternating-current voltage source through wires, first nematic phase liquid crystals with positive dielectric anisotropy are filled between theglass substrates, and the orientation direction of the first nematic phase liquid crystals is parallel to the inner surfaces of the two glass substrates. The invention has the advantages of large freespectrum range, small transmission spectrum full width at half maximum, large transmission wavelength adjustment range, small liquid crystal box thickness, short response time, simple structure and high reliability.

The invention discloses a single-longitudinal-mode narrow-linewidth optical fiber laser based on a double-coupling optical fiber ring and a Mach-Zehnder filter. The laser comprises a first optical isolator (1), a 980nm semiconductor laser (2), a 980 / 1,500nm wavelength division multiplexer (3), an erbium-doped fiber (4) with a concave cladding structure, an optical circulator (5), a non-pumped erbium-doped fiber (6), a fiber bragg grating (7), a passive resonant cavity (8) based on a double-coupling fiber loop and a Mach-Zehnder filter, a polarization beam splitter (9), a 1 * 2 optical coupler(10) and a second optical isolator (11), wherein the optical coupler (8) is composed of a first 2 * 2 optical coupler (12), a second 2 * 2 optical coupler (13) and a third 2 * 2 optical coupler (14).According to the passive resonant cavity based on the double-coupling optical fiber ring and the Mach-Zehnder filter, the two double-coupling optical fiber rings and the Mach-Zehnder filter are formed, the passive resonant cavity can serve as a narrow-band mode selection device to restrain multimode oscillation in the resonant cavity, and the non-pumped erbium-doped optical fiber serves as a saturable absorber; and the ultra-narrow band filtering effect can enable the annular cavity to realize stable single-frequency laser output. The laser has the advantages of narrow linewidth, low noise, high signal-to-noise ratio, simple structure and easiness in integration with an optical fiber system, and has huge potential in the fields of precision laser ranging, optical fiber communication, optical remote sensing and the like.

The invention discloses a linear dispersion combined prism optical splitter. The linear dispersion combined prism optical splitter is formed by combining two prisms which are manufactured from special materials and coated with films on the side surfaces by a mode of enabling the bottom surfaces to be clung to each other and the film-coated surfaces to be opposite to each other. The linear dispersion combined prism optical splitter is particularly suitable for the fields of spectrum analysis, spectrum detection and related fields. The linear dispersion combined prism optical splitter is on the basis of the control variable method and differential equation concept; the spreading direction of the line and the shape of the prisms are controlled according to the dispersion property of the first prism material; the nonlinear dispersion of the first prism is compensated according to the nonlinear dispersion of the second prism so as to obtain the linear dispersion combined prism optical splitter. The linear dispersion combined prism optical splitter can overcome the defect of nonlinear dispersion of single prism and has the advantages of being wide in free spectrum range, high in light energy utilization rate, high in generality, simple in structure, and small in cost.

The invention provides a multichannel feedback based Brillouin gyroscope, comprising a narrow line width laser source, an erbium-doped optical fiber amplifier, a first opto-isolator, a second opto-isolator, a 50: 50 coupler, a 90: 10 coupler, a multistage single mode optical fiber, a multimode optical fiber, a Perot filter and a photoelectric converter. The output terminal of the narrow line width laser source is connected with the input terminal of the erbium-doped optical fiber amplifier via the first opto-isolator, the output terminal of the erbium-doped optical fiber amplifier is connected with the input port of the 50: 50 coupler via the second opto-isolator, the two output ports of the 50: 50 coupler are respectively connected with the two coupling ports of the 90: 10 coupler by virtue of an optical fiber, the two through ports of the 90: 10 coupler are connected with the multistage single mode optical fiber and the multimode optical fiber, thus forming a resonant ring, the other output port of the 50: 50 coupler is connected with the input terminal of the Perot filter via an optical fiber, and the output terminal of the Perot filter is connected with the input terminal of the photoelectric converter.

The invention discloses a V-shaped coupled cavity double-wavelength semiconductor laser with continuously adjustable frequency interval. The first active resonant cavity and the second active resonant cavity are coupled in a V-shape at one end to form a multimode coupling region, the end face of the multimode coupling region has a cavity surface reflection surface, the other end of the first active resonant cavity and the first passive The source filters are connected in series through deep etched grooves to form one arm of the laser; the other end of the second active resonator and the second passive filter are connected in series through deep etched grooves to form the other arm of the laser; the first active Shallow etching grooves are arranged on the resonant cavity and the second active resonant cavity. The laser of the invention has the advantages of compact structure, simple manufacturing process, low cost, no external reference light source and the like.

Aspects of the present disclosure are directed to photon-pair sources based on an external-cavity laser comprising a gain element and a planar-lightwave circuit that includes a surface-waveguide-based mirror and a ring resonator that enables four-wave mixing, where the surface-waveguide mirror and the ring resonator reside within the gain cavity of the laser itself. As a result, photon-pair sources in accordance with the present disclosure can have: (1) a larger free-spectral range for the entire laser cavity to enable generation of a single wavelength to realize single-mode operation without additional stabilization; and (2) low laser noise, thereby enabling detection and use of the generated photon pairs.

The invention discloses a liquid crystal tunable filter and a configuration method thereof. The filter includes several cascaded Leo configuration filter units, and the Leo configuration filter unit consists of polarizers on both sides and a middle A birefringent optical element is formed, wherein part or all of the Leo configuration filter units are combined in two consecutive cascades or three consecutive cascades to form a combined unit. The merge method is stacked or fan merged. The birefringent optical element is a liquid crystal tunable wave plate, a fixed wave plate or a combination of a liquid crystal tunable wave plate and a fixed wave plate. The liquid crystal tunable filter of the present invention has the advantages of high pass rate, narrow half-width, high shielding rate, adjustable spectral range, strong stability, no need for mechanical rotation, and real-time controllable advantages. It can be widely used in Imaging, biology, medicine, materials, optics, optoelectronics, astronomy and other fields.

The invention relates to the technical field of optical fiber sensing, in particular to a silicon-core optical fiber-based Fabry-Perot sensor and a preparation method thereof. The Fabry-Perot sensor based on silicon core optical fiber of the present invention comprises ordinary single-mode optical fiber, optical fiber fusion joint end face, silicon core optical fiber and polishing end face, forms fusion joint end face after input optical fiber and silicon core optical fiber fusion, silicon core optical fiber is made of silicon core optical fiber The cladding is composed of the silicon core optical fiber core, the end face of the silicon core optical fiber is polished to form a polished end face, and the fusion end face and the polished end face form two mirror surfaces of the Fabry-Perot cavity of the silicon core optical fiber. The silicon core optical fiber Fabry Perot sensor obtained by the invention has high temperature sensitivity, laser power sensitivity and response speed, and the invention also has the advantages of simple structure, easy manufacture, good repeatability and the like.