104results about How to "Reduce splice loss" patented technology

The invention relates to a low-attenuation bending insensitive single mode fiber which comprises a core layer and wrapping layers. The low-attenuation bending insensitive single mode fiber is characterized in that the relative refractive index difference delta1 of the core layer ranges from 0.30% to 0.38%, the radius R1 of the core layer ranges from 3.5 micrometers to 4.5 micrometers, the four wrapping layers are arranged outside the core layer, the first wrapping layer is a first inner wrapping layer tightly surrounding the core layer, the relative refractive index difference delta2 of the first wrapping layer ranges from -0.02% to 0.02%, the radius R2 of the first wrapping layer ranges from 6.5 micrometers to 8.5 micrometers, the second wrapping layer is a second inner wrapping layer tightly surrounding the first inner wrapping layer, the relative refractive index difference delta3 of the second wrapping layer ranges from -0.02% to 0.02%, the radius R3 of the second wrapping layer ranges from 8 micrometers to 11 micrometers, the third wrapping layer is a downwards-concave wrapping layer tightly surrounding the second inner wrapping layer, the relative refractive index difference delta4 of the third wrapping layer ranges from -0.5% to -0.2%, the radius R4 of the third wrapping layer ranges from 12 micrometers to 20 micrometers, and the fourth wrapping layer is an outer wrapping layer tightly surrounding the downwards-concave wrapping layer and is a pure quartz glass layer. The low-attenuation bending insensitive single mode fiber can be completely matched with a G.652.D optical fiber, and therefore the low attenuation, the large effective area and the bending resistance can be better unified.

The invention discloses a micro-nano fiber grating laser writing method and a micro-nano fiber grating laser writing device. The method comprises the following steps of: tapering normal multi-mode fibers; manufacturing micro-nano fibers; and then taking 193 nm ultraviolet laser as a scribing means. The device comprises a fiber clamp, and an ArF excimer laser, a 45-degree full power reflector, a cylindrical lens and a phase mask plate which are sequentially arranged, wherein the ArF excimer laser is used for emitting 193 nm ultraviolet laser; the tapered fiber is fixed on the fiber clamp; micro-nano fiber regions of the fibers are arranged in front of the phase mask plate in parallel; the 193 nm ultraviolet laser emitted by the ArF excimer laser is reflected through the 45-degree full power reflector and then vertically emitted to the cylindrical lens; and the phase mask plate is arranged in front of the cylindrical lens. According to the method and the device, extra processing for the fibers is not required, the mechanical strength and the toughness of the fibers are kept, the cost is low, the scribing efficiency is high, the bandwidth is narrow, the mode is controllable and the repeatability is high.

The invention provides an improved nonzero dispersion-shifted single-mode optical fiber with large mode field distribution, comprising an optical fiber core layer, and a cladding covered on the optical fiber core layer; wherein, the optical fiber core layer comprises an internal core layer and an external core layer enclosing the internal core, both of which have different refractive indexes; the refractive index of the external core layer is gradually distributed; the cladding comprises an internal cladding, a ring-core cladding and an external cladding which are sequentially arranged from interior to exterior and have different refractive indexes; the external cladding layer is a pure SiO2 glass layer; the refractive index distribution of the optical fiber core layer meets the formula that n1 is more than n2 which is more than nc; the refractive index distribution of the cladding meets the formula that n4 is more than n3 which is more than nc or n4 is more than nc which is more than n3. The improved nonzero dispersion-shifted single-mode optical fiber has low nonlinear color-effect characteristic (namely large effective area), optimum dispersion and low dispersion efficiency, effectively solves the nonlinearity problem and polarization mode dispersion problem of high-speed communication, reduces the dispersion management cost and has low fusing loss, thus being applicable to large-capacity high-speed long-distance transmission system.

The invention discloses a polarization-maintaining fiber coupler. A coupling region of the polarization-maintaining fiber coupler is made of single-mode optical fibers, an input end of the polarization-maintaining fiber coupler at least contains a polarization-maintaining optical fiber, an output end which is directly communicated with the input end is one single-mode optical fiber, the input end of the polarization-maintaining fiber coupler at least contains one single-mode optical fiber, an output end which is directly communicated with the input end is the polarization-maintaining optical fiber, and the polarization-maintaining optical fibers of the input end and the output end are fused with the corresponding single-mode optical fibers in the coupling region respectively. A method for preparing the polarization-maintaining fiber coupler comprises the following steps that: firstly, a heat sealer is used to prepare two-node optical fibers; secondly, the optical fibers are arranged and axially positioned according to the design requirement; and finally, a plurality of the single-mode optical fibers in the middle are fused and drawn into the coupling region. In the polarization-maintaining fiber coupler, the coupling region is formed by drawing the single-mode optical fibers, so a device has the characteristics of no sensitivity to the polarization and temperature environment, and the stability and the reliability of the device are greatly improved. The invention also discloses an all-fiber optical current sensor.

The invention discloses a polarization-maintaining photonic crystal fiber and panda fiber welding method. The polarization-maintaining photonic crystal fiber and panda fiber welding method is characterized by comprising a step 1 of selecting an initial position of a fiber, a step 2 of aligning a polarization shaft, and a step 3 of welding. The polarization-maintaining photonic crystal fiber and panda fiber welding method realizes better matching of two fiber mode fields and lowering welding consumption by controlling collapse of an air hole of a photonic crystal fiber and a diameter at the welding point of the panda fiber. The polarization-maintaining photonic crystal fiber and panda fiber welding method lowers welding consumption and improves welding intensity by adding a propelling distance in a fiber welding process appropriately. By adopting a novel welding machine and an end face imaging and shaft alignment technology, the polarization-maintaining photonic crystal fiber and panda fiber welding method can realize alignment of the polarization shafts of both the photonic crystal fiber and the panda fiber and improve shaft alignment precision. The polarization-maintaining photonic crystal fiber and panda fiber welding method, disclosed by the invention, has the advantages of being simple in technology, only needing once welding, and being easy to operate, good in repeatability and applicable for welding between photonic crystal fibers of the other types and traditional single-mode fibers.

The invention provides a crosstalk suppression type multi-core optical fiber beam splitter with low insertion loss. The multi-core optical fiber beam splitter is characterized by being composed of aninput standard single-mode optical fiber, a multi-clad optical fiber, a porous quartz capillary sleeve and a multi-core optical fiber. Fiber cores of the single-mode optical fiber and the multi-clad optical fiber have the same single-mode field distribution; the multi-clad optical fiber is embedded into the porous quartz capillary sleeve; the diameter of the fused and tapered multi-clad optical fiber is reduced; optical fields in the fiber cores are converted in inner claddings; fundamental mode transmission is kept; and a mode field of an output end is matched with that of the multi-core optical fiber. The specially designed multi-clad optical fiber can effectively reduce the insertion loss of a device and effectively suppress the inter-core crosstalk of the device. The multi-core opticalfiber beam splitter can be used for low-loss and low-crosstalk beam splitting connection of the multi-core optical fiber, and is particularly suitable for beam splitting connection of the multi-coreoptical fiber with the large fiber core number and the high fiber core density.

The invention discloses a 780 nm high-power optical-fiber femtosecond laser device. The laser device comprises a laser device seed source, a laser spreading and amplifying module, a laser compression module and a laser frequency doubling module, the laser device seed source and the preceding modules are sequentially connected, the laser spreading and amplifying module is composed of a chirped pulse spreading sub module, a pulse separation sub module and an optical fiber amplifying sub module, and the laser device seed source and the modules all work at the waveband of 1560 nm. A mixed pulse spreading mode is adopted, pulses are spread from 100 fs to 1ns in a small work space, the amplified pulses are compressed to below 100 fs through non-linear compression of a single-mode fiber, and ultimately the pulses reach 780 nm after frequency doubling of non-linear crystals. The laser device has the advantages of being high in stability, simple in structure, small and ingenious in size, low in cost and the like.

The invention discloses a multi-cladding optical fibre and a multi-core optical fibre coupler. The multi-core optical fibre coupler comprises N multi-cladding optical fibres and a bushing; the multi-cladding optical fibre comprises a fibre core and multiple claddings encircling the fibre core; the multiple claddings sequentially comprise an inner cladding, a sunken inner cladding, an annular cladding, an outer cladding, a sunken outer cladding and a mechanical cladding from inside to outside; the multi-core optical fibre coupler is obtained by inserting the N multi-cladding optical fibres intothe bushing, tapering and cutting the bushing at one point in the middle of the bushing and welding a multi-core optical fibre; after the N multi-cladding optical fibres are inserted into the bushingand tapered, the fibre core, the inner cladding, the sunken inner cladding and the annular cladding of each multi-cladding optical fibre of the tapered end form a tapered fibre core; and the outer cladding, the sunken outer cladding and the mechanical cladding form a tapered cladding. According to the multi-core optical fibre coupler provided by the invention, after being tapered, the multi-cladding optical fibre can be in low-loss welding with the multi-core optical fibre, and also can be in low-loss welding with a standard single-mode optical fibre; and furthermore, the macrobend loss is relatively low.

The invention belongs to the technical field of fiber couplers, and particularly relates to a hollow-core antiresonance photonic crystal fiber coupler and application thereof. The fiber coupler is formed by two hollow-core antiresonance fibers with polished side faces. The basic structure of each hollow-core antiresonance fiber comprises a fiber core, a circle of micro-capillary inner covering layer around the fiber core and an outer covering layer covering the exterior of the micro-capillary inner covering layer. The polished faces of the hollow-core antiresonance fibers are arranged on the outer covering layer and are attached to each other and subjected to fusion or tapering, so a fiber coupler is manufactured. Before the tapering or during the tapering, the ring distance of two rings near the attached faces is reduced or increased, so the mode coupling of the fiber core of the two hollow-core antiresonance fibers is optimized. The fiber coupler is simple in design and highly practical, can be used for pulse laser, especially, full-fiber coupling and laser beam splitting of femtosecond laser and can be applied in a hollow-core fiber gyroscope to replace a solid fiber coupling module.

The invention discloses an optical cable splicing method. The optical cable splicing method includes the following steps: (1) selecting an optical cable with the appropriate length and winding the end face of the optical cable with adhesive tape; (2) peeling the optical cable, wherein another person makes the preparation work for tools and materials needed by an optical cable splice closure, an optical cable fusing device and fusing while one person peels the optical cable; (3) conducting the fiber core splicing working procedure; (4) in the optical cable splicing process, conducting real-time measurement at the other end of an optical fiber while fusing is carried out by another worker, and instantly notifying the worker to conduct fusing again when it is found that fusing losses exceed the standard. By means of the method, the optical cable splicing process is reasonable, the optical cable fusing losses are small, time is saved, the process is good, the optical cable splicing quality is improved, the communication quality is better improved, and the better communication guarantee is provided for other relevant departments; meanwhile, the attractive appearance is guaranteed, and the optical cable operation quality is guaranteed.

An optical fibre with a multiple-sector fiber core at the periphery of a multiple-sector area of the circular fiber core, and a fabrication method thereof belong to the fields of the high-power broadband fiber laser and the special optical fibre, which overcome the problem that a single-core doubly-clad optical fibre with multiple rare-earth ion doped regions is limited to bear optical power and the problem that a block clad optical fibre core layer has a limited diameter. Sector rare-earth ion doped regions 1 to N are all the same in optical refractive index, radius and radian, and form a complete circular fibre core, wherein N is an integer greater than or equal to 3 and less than or equal to 9; sector fibre cores 1 to M having the same radius and the same radian a are evenly distributed around the circular fibre core in an inner cladding layer, wherein M is an integer greater than or equal to N or less than or equal to 32 and a is greater than or equal to pi/2M and less than or equal to 2pi/M; distances between the vertexes of the sector fibre cores 1 to M and the outer circle of the circular fibre core are equal; and the circular fibre core is equal to the sector fibre cores 1to M in rare-earth ion doping type set. The fabrication method comprises fabricating circular fibre core fine rods and sector fibre core fine rods and organizing the fine rods into the optical fibre.The yield of the optical fibre is high and the welding loss of the optical fiber with a single-mode optical fibre is low; and single-mode operation in large-mode area is realized.

The invention discloses a preparation method of a full optical fibre quarter-wave plate, which comprises the following steps: step1, splicing one end of a circular core wire polarization-preserving optical fibre used for transmission and one end of a section of single mode optical fibre in a fusion mode, and splicing one end of a circular core sensing optical fibre with the other end of the single mode optical fibre in a fusion mode; step 2, taking at least a section of the optical fibre as an auxiliary optical fibre, placing the auxiliary optical fibre to be parallel and abutting against one side or both sides of the single mode optical fibre of the spliced fibre structure in the step 1, and making a main shaft of the circular core wire polarization-preserving optical fibre form an angle of 45 DEG with a placed plane; and step 3, heating and melting concatenated single mode optical fibre areas with high temperature, making the single mode optical fibre of the heating area and the auxiliary fibre achieve a melting state and be melted together, continuously heating and making the single mode optical fibre of a circular core gradually be elliptical, and controlling the heating and welding time to prepare and form the quarter-wave plate. The preparation method utilizes common single mode optical fibres to prepare the quarter-wave plate with tiny loss, and also can be used for preparing other set wave plates.

The process of preparing fiber preformed rod includes deuterium-hydrogen displacement reaction on quartz rod with low hydroxyl radical content and high purity for deuterium atom to occupy the non-bridge oxygen bond in quartz glass so as to reduce the probability of hydroxyl radical to diffuse, plasma flame etching to eliminate surface adsorbed hydroxyl radical of the quartz rod completely, depositing GeO2 and SiO2 onto the surface of the quartz rod, combined loose perform rod with central quartz rod, and dewatering and sintering in a sintering furnace to obtain transparent fiber preformed rod. The present invention is suitable for large- scale production and has low production cost, and the fiber preformed rod may be drawn into mono-mode fiber with low attenuation at 1383 nm wavelength, high hydrogen ageing resistance and very low PMD.

The invention discloses a single-mode optical fiber and a multi-core optical fiber coupler, which belong to the technical field of optical fibers. The single-mode optical fiber comprises a fiber core,a first outer cladding layer, a sunken outer cladding layer and a mechanical cladding layer which are sequentially arranged from inside to outside, wherein refractive indexes in the fiber core, the first outer cladding layer, the sunken outer cladding layer and the mechanical cladding layer are uniformly distributed; the refractive index of the interface of the fiber core and the first outer cladding changes suddenly, the refractive index of the interface of the sunken outer cladding and the mechanical cladding changes suddenly, and the refractive index of the sunken outer cladding is smallerthan that of the mechanical cladding. The optical fiber coupler comprises a sleeve and a single-mode optical fiber, the single-mode optical fiber is nested in the sleeve, and one end of the sleeve istapered; one end of the sleeve tapering is used for being welded with the multi-core optical fiber; and each single-mode optical fiber in the non-tapering end is respectively welded with the corresponding standard single-mode optical fiber. The problem of large loss of the existing multi-core optical fiber coupler is solved.

The invention relates to an optical cable joint method based on a cable holder. The optical cable joint method comprises the following steps of (1) selecting a plurality of cable bare fibers with same mode field diameter; (2) paving the cable bare fibers; (3) fixing a joint between the two cable bare fibers by using the cable holder; (4) cutting a fiber end face of each cable bare fiber through a fiber end face cutter; and (5) welding the joint through a welding machine, testing continuing loss of a welding point through an optical time domain reflectometer (OTDR) while welding in a welding process, and welding the position which does not meet requirements again. Compared with the prior art, the optical cable joint method has the advantages of optimizing cable joint procedures, reducing optical fiber welding loss and the like.

The invention discloses a method for manufacturing a bent insensitive optical fiber preformed rod, and belongs to an optical communication technology. The bent insensitive optical fiber preformed rod prepared by the prior art has the defects of insufficient bending performance, high optical fiber attenuation, high OH- content, low optical fiber mechanical strength, complex process and the like. When a core rod is manufactured by using a vapor axial deposition (VAD) process, 1 to 2 paths of blast lamps for synchronously depositing a doped layer are increased according to the profile of the designed optical fiber preformed rod, a coating is manufactured on the vitrified core rod by using an outside vapor deposition (OVD) process or a sleeve process, and finally the bent insensitive optical fiber preformed rod is obtained. The optical fiber preformed rod prepared by the method has the advantages of low optical fiber attenuation, low OH- content, high mechanical strength and the like; themethod can manufacture the required structure model according to the requirement; the optical fiber drawn by using the manufactured optical fiber preformed rod has excellent bending performance, and is suitable for the application occasions of fiber to the home (FTTH) access, small optical devices, optical cables with small bending radius requirements and the like.

The invention discloses a small-diameter solid core polarization-maintaining photonic crystal fiber of a four-layer structure and belongs to the technical field of microstructure fibers. The concrete structure refers to that a section is round, and the fiber sequentially comprises a coating layer, a cladding and cladding air pores from outside to inside. The cladding air pores are of a four-layer symmetric structure and are arrayed in a hexagon. The centers of the cladding air pores are concave parts, two large air pores are formed in the centers in the x-axis direction to form shape birefringence of the fiber. The diameter d of each cladding air pore is 3.0-3.8 micrometers; the distance A between every two adjacent cladding air pores is 5.4-6.2 micrometers; the diameter D of each large air pore is 5.5-6.4 micrometers, the duty ratio d/Lambada is 0.55-0.65, and the range of the normalized frequency Lambada/Lambada is 3.5-4. The fiber has the advantages that gyro precision is substantially improved within a certain size limit, the temperature performance of an fiber gyro and the temperature stability of fiber birefringence are improved, and the temperature sensitivity of the fiber gyro is reduced; an fiber mode field diameter is closer to that of a common polarization-maintaining fiber, so the welding loss is smaller; the diameters of the cladding and the coating layer are smaller than those of a current fiber, so gyro miniaturization is facilitated.

The invention provides a clustered fiber Bragg grating sensor, which includes a plurality of optical fibers. Each optical fiber is provided with a plurality of gratings through the etching process. The plurality of optical fibers with the gratings etched thereon are clustered and packaged within a single plane or a beam tube. The clustered fiber Bragg grating sensor is small in splicing loss, simple in operation process, high in detection resolution, easy to package, high in survival rate and small in size. Meanwhile, the line detection, the surface detection and the body detection, subjected to large-area temperature strain, are enabled.