47results about How to "Reduce optical power density" patented technology

The invention provides a TM-polarization GaAsP/GaInP active-region 808nm quantum-well laser. The laser structurally comprises a substrate, a buffer layer, a type-N lower limit layer, a lower waveguide layer, a quantum well layer, an upper waveguide layer, a type-P upper limit layer, and an ohmic contact layer sequentially from bottom to top. The upper waveguide layer and the lower waveguide layer are made of aluminum-free material GaInP. The quantum well layer is made of GaAsP material. The waveguide layer and the quantum well layer form a wide-waveguide aluminum-free active region. The laser has the advantages that the influence of Al oxidization, growth interface roughness and accessory electric field at cavity surface upon the reliability in high power output, long service life and the like of the laser can be reduced effectively, the waveguide layer and the limit layers are optimally designed into wide-waveguide asymmetric structures, and internal loss can be reduced effectively, and maximum output power and reliability can be improved.

The invention discloses a high-power laser diffraction type spatial filter. The left side of the high-power laser diffraction type spatial filter is provided with an interstage isolation filter of which the central axis is a vertical line BC, the middle of the high-power laser diffraction type spatial filter is provided with a group of gain medium of which the central axis is a transverse line CD, the right side of the high-power laser diffraction type spatial filter is provided with a multi-pass cavity filter of which the central axis is a vertical line DE, the central axis of the entire device forms a BCDEF broken line, one optical grating which enables light beams to be deflected at 90 degrees is respectively arranged at a point B, a point C, a point D and a point E, the optical gratings are separate type volume Bragg optical gratings or double-piece integrated type optical gratings, and one reflecting mirror is arranged at a point F. The invention uses an optical grating double-pass spatial filter component which does not have a lens and a pinhole and has compact appearance to replace a pinhole filter in a multi-pass amplifier, can realize the wider width of a diffraction frequency band and can meet the requirement of short-pulse and ultrashort-pulse spatial filtering; the borne laser power is higher, and the requirement of high-power laser spatial filtering can be met, thereby eliminating the probability that laser burns out the filter component because of no lens and no pinhole in the device.

The invention discloses a low-loss large-effective area single mode fiber and a manufacturing method of the low-loss large-effective area single mode fiber, and relates to the field of optical fibers. The low-loss large-effective area single mode fiber comprises a quartz glass cladding, an internal coating and an external coating, wherein the quartz glass cladding, the internal coating and the external coating are arranged in sequence from inside to outside; the inside of the quartz glass cladding comprises a first fiber core area, a second fiber core area, a third fiber core area, a fourth fiber core area and a refractive index concave cladding, wherein the first fiber core area, the second fiber core area, the third fiber core area, the fourth fiber core area and the refractive index concave cladding are arranged in sequence from inside to outside; the refractive index concave cladding is subjected to deposition through a PCVD process; the quartz glass cladding is manufactured through an OVD process or a sleeving process. According to the low-loss large-effective area single mode fiber and the manufacturing method of the low-loss large-effective area single mode fiber, the scattering loss of the low-loss large-effective area single mode fiber and the additional loss of the low-loss large-effective area single mode fiber in a bent state can be reduced; due to the fact that the spire distribution of fiber core basic mode electromagnetic field power is adjusted into flattop distribution, optical power density is reduced, the effective area of the low-loss large-effective area single mode fiber is enlarged, the nonlinearity of the low-loss large-effective area single mode fiber is reduced, the incident power of an optical fiber communication system is increased by 0.4-2.6 dB, and the low-loss large-effective area single mode fiber is suitable for mass production.

The invention provides a high-power optical fiber end cap and a manufacturing method thereof. The optical fiber end cap comprises a double-clad optical fiber, a core-free optical fiber and a quartz rod which are coaxially arranged; the quartz rod comprises a first cylindrical section, a circular table section and a second cylindrical section which are coaxially connected in sequence, the diameterof the first cylindrical section is smaller than that of the second cylindrical section; the double-clad optical fiber is connected with one end of the core-free optical fiber in a welding mode, and the other end of the core-free optical fiber is connected with one end of the first cylindrical section in a welding mode; the diameter of the cladding layer of the core-free optical fiber is larger than or equal to the diameter of the double-clad optical fiber; and the diameter of the cladding layer of the core-free optical fiber is smaller than or equal to the diameter of the first cylindrical section. The laser firstly passes through the core-free optical fiber, so that energy is expanded, and the light power density in the connecting place of the output end plane and the quartz rod is lowered; by selecting the proper length of the core-free optical fiber, the output light spot can be large enough when the laser outputs from the core-free optical fiber, so that the optical power densityon the output surface can be effectively reduced; and meanwhile, energy is not output from the side surface of the core-free optical fiber, and loss of energy is avoided.

In a semiconductor-laser device: a compressive-strain quantum-well active layer is made of Inx3Ga1. x3As1-y3Py3 (0<x3<=0.4 and 0<=y3<=0.1); tensile-strain barrier layers made of Inx2Ga1-2AS1-y2P1-y2 (0<=x2<0.49y2 and 0<y2<=0.4)are formed above and under the compressive-strain quantum-well active layer; and optical waveguide layers being made of either p-type or i-type In0.49Ga0.51P are formed above the upper tensile-strain barrier layer and under the lower tensile-strain barrier layer. Preferably, the absolute value of a sum of a first product and a second product is less than or equal to 0.25 nm, where the first product is a product of a strain and a thickness of said compressive-strain active layer, and the second product is a product of a strain of said lower and upper tensile-strain barrier layers and a total thickness of the lower and upper tensile-strain barrier layers.

The present invention provides improved collimating lens assemblies (32), improved methods of reducing the optical power density in collimating lens assemblies, and to improved fiber optic rotary joints (31) incorporating such improved collimating lens assemblies. The improved collimating lens assembly broadly includes: a singlemode fiber (38) terminating in a distal end; a step-index multimode fiber (44) having a proximal end abutting to the singlemode fiber distal end, and having a distal end; a graded-index multimode fiber (45) having a proximal end abutting the step-index multimode fiber distal end, and having a distal end; and a collimating lens (34) longitudinally spaced from the graded-index multimode fiber distal end by an intermediate air gap (43), and operatively arranged to collimate light rays emanating from the graded-index multimode fiber distal end. The improved collimating lens assembly is characterized by the fact that there is no epoxy, silicone gel or index-matching material between the graded-index multimode fiber distal end and the collimating lens. Rather, these various elements are fusion-spliced together. The improved collimating lens assembly is capable of handling energy levels that are typically used in various wavelength division multiplexing techniques.

The invention relates to a high-power polarization-maintaining optical fiber and a preparation method thereof, and belongs to the technical field of polarization-maintaining optical fibers. The crosssection structure of the optical fiber sequentially comprises a fiber core (102), a first cladding (104), a second cladding (105), an outer cladding (106) and an external coating (107) from inside tooutside, the fiber core (102) is fluorine-doped quartz containing rare earth, alkali metal and a dispersing agent, and the first cladding (104) is filled with two shallow fluorine-doped quartz rods symmetrically distributed along the fiber core (102) to form a fluorine-doped area (101); the first cladding (104) is also filled with two stress rods which are symmetrically distributed along the fibercore (102) to form a stress area (103); and the symmetry axis of the fluorine-doped area (101) and the symmetry axis of the stress area (103) perpendicularly intersect at the center of the fiber core(102). According to the optical fiber, the existence of spiral light can be reduced to a greater extent, the input of pump light is increased, the reflection frequency of a cladding is improved, thereflection path is shortened, and the effects of reducing the optical power density and improving the laser output power are achieved.

As edge-emitting semiconductor laser incorporating a narrow waveguide design is disclosed. The narrow waveguide expands the lateral mode size, creates a large modal spot size, and insures higher-order modes are beyond cutoff. Separate current confinement allows the current injection region to match the mode size. The resulting device exhibits single-mode operation with a large spot-size to high output powers.

A method of producing a personalized security document or article includes providing a substrate which is transparent at least to visible light. A diffractive optical microstructure is formed in a substantially opaque layer disposed on a surface of the substrate. The diffractive structure comprises a plurality of apertures formed in the opaque layer, such that when the structure is suitably illuminated, for example by a beam of collimated light, a projected image is generated which is unique to a particular individual. Also, personalized security documents or articles made in accordance with the method.

A light input/output terminal module 100 comprises a jacket tube 110 and a flange 120. A glass portion 20 of the optical fiber is inserted in the center portion thereof. To efficiently remove the leaked light in a cladding 22 to the jacket tube 110, the jacket tube 110 is made of silica glass or the same material as that of the cladding 22. The jacket tube 110 is fixed by fusion splicing or adhesion to the cladding so as to integrally unify the jacket tube 110 and the cladding 22. The beam diameter at the fiber end portion is enlarged by an optical component which fusion bonds the tip end of the optical fiber to the coreless fiber so that the optical power density at the light input/output terminal module is reduced.

The embodiment of the invention discloses a photoelectric detector, and the photoelectric detector comprises a silicon layer which comprises a doped region of a first doping type; a germanium layer incontact with the silicon layer, wherein the germanium layer comprises a doped region of a second doping type; a first layer of waveguide, wherein the first layer of waveguide comprises a first detection coupling region arranged above the germanium layer; a second layer of waveguide which comprises a second detection coupling region arranged on the side surface of the germanium layer, wherein thefirst layer of waveguide and the second layer of waveguide are used for transmitting optical signals, and the first layer of waveguide and the second layer of waveguide are used for coupling the optical signals to the germanium layer through the first detection coupling region and the second detection coupling region respectively, and the germanium layer is used for detecting the optical signal and converting the optical signal into an electric signal.

A structure of high power edge emission laser diode that has plural mode extension sublayers with a chirp periodic distribution is provided. The Near Field Pattern (NFP) is an L shape, and the high intensity portion is nicely overlapped with the multi quantum wells. Furthermore, the low intensity portion will extend to the n-type cladding as it can as possible. Accordingly, the optical power density on the mirror surface of the high power edge emission laser diode is lower down and the vertical divergence angle is decreased, so as to prolong its lifetime.

The invention discloses a high-power laser for a 808nm ceiling light field and relates to the technical field of a semiconductor laser; the high-power laser comprises a substrate, wherein a buffer layer, a lower limiting layer, a lower light-field active layer, a lower waveguide layer, a quantum well layer, an upper waveguide layer, an upper light-field active layer, an upper limiting layer and an electrode contact layer are sequentially grown on the substrate from top to bottom; the lower light-field active layer is made of a highly doped N-type AlGaAs material, and the upper light-field active layer is made of a highly doped P-type AlGaAs material. The light field top of the fast axis is uniformly distributed, so that the optical power density in the active region can be further reduced, and reliability and durability of the laser are improved.

The invention discloses a projection type laser heating system and a 3D printer. The projection type laser heating system comprises an infrared laser, a laser power adjustment device, a beam splittergroup, not less than two projection assemblies and a workbench; the workbench is provided with a preheating device and is used for laying a powder material; the laser power adjustment device comprisesa first rotating clamping assembly, a power meter, a first half-wave plate, a polarization beam splitter mirror and a beam expander group; the first half-wave plate, the polarization beam splitter mirror and the beam expander group are sequentially distributed in the same direction; the first half-wave plate is arranged on the first rotating clamping assembly; the not less than two projection assemblies are arranged at the exit direction of the beam splitter group; and each projection assembly comprises a DMD chip. The projection type laser heating system further comprises a control system; and the control system controls the first rotating clamping assembly and the DMD chips, and independently controls the projection shape and direction of each DMD chip, so that the shapes of the DMD chips projected to the workbench are the same and are coincident. With the adoption of the technical scheme, projection type laser heating can be realized in 3D printing.

The invention provides a mode control semiconductor device and a preparation method thereof, the mode control semiconductor device is provided with a front cavity surface and a rear cavity surface which are oppositely arranged, and the mode control semiconductor device comprises a semiconductor substrate layer, an active layer positioned on the semiconductor substrate layer, a first limiting layer and a second limiting layer located on the semiconductor substrate layer and located on the two sides of the active layer respectively, a first waveguide layer located between the first limiting layer and the active layer, a second waveguide layer located between the second limiting layer and the active layer, and having the thickness smaller than or equal to that of the first waveguide layer, and a first dimming layer located in the part, adjacent to the front cavity surface, of the second limiting layer; the refractive index of the first dimming layer is smaller than that of the second limiting layer, and the width of the first dimming layer is gradually increased in the direction from the rear cavity surface to the front cavity surface. According to the mode control semiconductor device, the optical catastrophe damage resistance threshold power of the front cavity surface is improved, and meanwhile, the coupling loss, the production process complexity and the cost are reduced.