CN202256755U

CN202256755U - Manufacture device of triangular optical fiber grating

Info

Publication number: CN202256755U
Application number: CN2011203313194U
Authority: CN
Inventors: 周倩; 宁提纲; 吴娇
Original assignee: Beijing Jiaotong University
Current assignee: Beijing Jiaotong University
Priority date: 2011-09-06
Filing date: 2011-09-06
Publication date: 2012-05-30
Anticipated expiration: 2021-09-06

Abstract

The utility model discloses a manufacture device of a triangular optical fiber grating, which is suitable for the fields of fiber-optical communication, fiber-optical sensors, traffic information engineering, control techniques and the like. The triangular optical fiber grating is manufactured by utilizing a speed expansion system formed by a lens and adopting an identical photo mask. Wavelength regulation of the triangular optical fiber grating is very simple. An excimer laser (1) of the manufacture device serves as a read-in light source, the speed expansion system (2) and the phase photo mask (3) are placed perpendicular to a main optical axis, and an optical fiber (4) and the phase photo mask (3) are placed at an angle of 0-45 degrees. Ultraviolet light sent out by the excimer laser (1) is broadened after penetrating through the speed expansion system (2), and the broadened ultraviolet light beam is incident on the phase photo mask (3) and generates interference fringe. The interference fringe utilizes mutation induced by laser to generate refractive index modulation in a fiber core of the optical fiber (4) very close to the phase photo mask (3), and accordingly the triangular optical fiber grating is formed.

Description

A kind of producing device of triangle grating

Technical field

The utility model relates to a kind of producing device of fiber grating, is applicable to fields such as optical fiber communication, Fibre Optical Sensor, Traffic Information Engineering & Control technology.

Background technology

Fiber grating is to utilize the photosensitivity in the optical fiber to process.Fiber grating is divided into bragg grating and LPFG according to the cycle, the bragg grating cycle generally below 1um, and the cycle of LPFG at tens um to hundreds of um.Bragg grating abbreviates fiber grating under many circumstances as, and it is according to cyclophysis, is divided into even constant uniform fiber grating of cycle, perhaps the chirped fiber grating that changes vertically of cycle.Uniform fiber grating reflectance spectrum bandwidth is generally less than 0.5nm, and the bandwidth of chirped fiber grating is from 0.1nm to tens nm, even nm is wide more than 100.

Fiber grating is relatively more responsive to the variation of external environments such as temperature, pressure, strain, have volume little, insert loss low, compatible with optical fiber, can imbed advantage such as intellectual material, obtained application widely at optical fiber communication and sensory field.And chirped fiber grating also has good dispersion compensation ability, is dispersion compensation device commonly used in the jumbo dense wavelength division multiplexing system, and this makes the research of chirped fiber grating become very important.

The ultimate principle of fiber-optic grating sensor is to utilize fiber grating spectrum; Especially its peak is with the characteristic of temperature and STRESS VARIATION; The change transitions that the external world is measured is the variation of bragg wavelength, observes the wavelength shift of fiber grating and just can judge size to be measured.In order to detect wavelength change, require simple and easy, cheap spectral measurement method, to replace the spectrometer of the costliness of in the laboratory, using usually.Triangle grating (triangle Bragg grating); Perhaps be referred to as the triangle bragg grating and belong to nonlinearly chirped fiber grating; Its characteristic is: in its bandwidth range, the change of reflectivity and lambda1-wavelength is linear in certain wavelength coverage.Utilizing this characteristic of triangle grating, is the signal of optical power change with the conversion of signals of wavelength change.Therefore triangle grating can be widely used at sensory field of optic fibre.

Usually having two kinds of methods to produce warbles: the one, and the modulation amplitude method of warbling, promptly the cycle of grating remains unchanged, but along the grating refractive index modulation variation; The 2nd, utilize mask plate pitch to change the cycle that changes grating, and index modulation remain unchanged.It is a lot of to change the method that the grating cycle changes, as non-homogeneous cycle mask means, ablation process to optical fiber stress application gradient or temperature gradient method, prestress optical Fiber Method when writing grating, in the standard mask method writes the curved fiber method, in the holographic interference ablation process, utilize wavefront different curvature method etc.But these methods have many weak points, and, writing station limited like the Bragg wavelength tunability adjusted difficulty, mechanical stability and write the light beam spatial coherence and require high.

The utility model content

The utility model technical matters to be solved is the deficiency that overcomes the method that changes the variation of phase mask plate cycle, proposes a kind of producing device of triangle grating.

The technical scheme of the utility model:

A kind of triangle grating producing device, it comprises excimer laser, phase mask plate, optical fiber, optical fiber and phase mask plate are 0 °～45 ° placements.Between excimer laser and phase mask plate, establish an expansion speed system; Excimer laser is as writing light source, and the expansion speed system places perpendicular to primary optical axis.

The parallel ultraviolet that excimer laser produces is through expansion speed system broadening; Ultraviolet light beam behind the broadening incides on the phase mask plate and produces interference fringe; Interference fringe is utilized photo-induction to become and in the fibre core of optical fiber, is produced index modulation, forms triangle grating.

Through changing the wavelength that distance between optical fiber and the phase mask plate can change the triangle grating that writes, along with the increase of distance, wavelength increases gradually.

The beneficial effect of the utility model:

The producing device structure of a kind of triangle grating that the utility model proposes is very simple, only needs excimer laser, lens, phase mask plate and optical fiber, and cost is low, is easy to realize.This producing device just can be produced triangle grating through single exposure.Change the triangle grating that distance between optical fiber and the phase mask plate can write different wave length, the wavelength regulation of the triangle grating that writes is very easy to.

Description of drawings

Fig. 1 adopts the triangle grating producing device synoptic diagram of a convergent lens and a divergent lens composition expansion speed system.

Fig. 2 adopts two convergent lenses to form the triangle grating producing device synoptic diagram of expansion speed system.

Fig. 3 adopts the triangle grating producing device synoptic diagram of a convergent lens, a divergent lens and an offset lens composition expansion speed system.

Fig. 4 adopts the triangle grating producing device synoptic diagram of two convergent lenses and two divergent lens composition expansion speed systems.

Among the figure: excimer laser 1, expansion speed system 2, phase mask plate 3, optical fiber 4, black cloth 5, first convergent lens 21, first divergent lens 22, second convergent lens 23, second divergent lens 24, offset lens 25.

Embodiment

Below in conjunction with accompanying drawing the present invention is further described.

Embodiment one

Present embodiment combines accompanying drawing 1 to further specify.

A kind of producing device that adopts the triangle grating of a convergent lens and a divergent lens composition expansion speed system, as shown in Figure 1.

This producing device comprises: expansion speed system 2, phase mask plate 3, optical fiber 4, black cloth 5 that excimer laser 1, first convergent lens 21 and first divergent lens 22 are formed.

Excimer laser 1 is as writing light source; Lens are put and are first convergent lens 21, first divergent lens 22 in proper order in the expansion speed system 2; Expansion speed system 2 all places perpendicular to primary optical axis with phase mask plate 3; And the center that makes phase mask plate 3 is just in time on primary optical axis, and the upper end 42 of optical fiber is close to the upper end 32 of phase mask plate and is placed, and makes optical fiber 4 with respect to the phase mask plate 31 ° of angle that tilts.The focal length of first convergent lens 21 is 5mm, the focal length 50mm of first divergent lens 22, and the distance between first convergent lens 21 and first divergent lens 22 is 55mm, the distance between first divergent lens 22 and the phase mask plate 3 is 5mm.

The first half of expansion speed system 2 is covered with black cloth 5; The parallel ultraviolet that excimer laser 1 produces is through the latter half broadening of expansion speed system 2; Ultraviolet light beam behind the broadening incides on the phase mask plate 3 and produces interference fringe; Interference fringe is utilized photo-induction to become in the fibre core of that part of optical fiber that optical fiber 4 makes public and is produced index modulation, forms triangle grating.

The wavelength of the triangle grating that the described producing device of present embodiment is made is 1535nm.

Embodiment two

Present embodiment combines accompanying drawing 2 to further specify.

A kind of producing device that adopts two convergent lenses to form the triangle grating of expansion speed system, as shown in Figure 2.

This producing device comprises: expansion speed system 2, phase mask plate 3, optical fiber 4 that excimer laser 1, first convergent lens 21 and second convergent lens 23 are formed.

Excimer laser 1 is as writing light source; Lens are put order and are first convergent lens 21, second convergent lens 23 in the expansion speed system 2; Expansion speed system 2 places perpendicular to primary optical axis with phase mask plate 3; And making the center of phase mask plate 3 upwards depart from primary optical axis 5mm, the upper end 42 of optical fiber is 5mm with the upper end of phase mask plate 32 distances, and makes optical fiber 4 with respect to 15 ° of angles of phase mask plate 3 inclinations; The focal length of first convergent lens 21 is 10mm, the focal length 30mm of second convergent lens 23, and the distance between first convergent lens 21 and second convergent lens 23 is 40mm, second convergent lens 23 is 100mm with the distance of phase mask plate 3.

The parallel ultraviolet that excimer laser 1 produces is through expansion speed system 2 broadenings; Ultraviolet light beam behind the broadening incides on the phase mask plate 3 and produces interference fringe; Interference fringe is utilized photo-induction to become in the fibre core of that part of optical fiber that the optical fiber 4 with phase mask plate 3 close proximity makes public and is produced index modulation, forms triangle grating.

The wavelength of the triangle grating that the described producing device of present embodiment is produced is 1545nm.

Embodiment three

Present embodiment combines accompanying drawing 3 to further specify.

A kind of producing device that adopts the triangle grating of a convergent lens, a divergent lens and an offset lens composition expansion speed system, as shown in Figure 3.

This producing device comprises: excimer laser 1, first convergent lens 21 and first divergent lens 22 and expansion speed system 2, phase mask plate 3, the optical fiber 4 that offset lens 25 is formed.

Excimer laser 1 is as writing light source; Lens are put and are first convergent lens 21, first divergent lens 22, offset lens 25 in proper order in the expansion speed system 2; Expansion speed system 2 places perpendicular to primary optical axis, and phase mask plate 3 is 30 ° of angles with primary optical axis, and makes the center downward bias of phase mask plate 3 leave primary optical axis 50mm; Optical fiber 4 is placed perpendicular to primary optical axis, and the upper end 42 that makes optical fiber is 10mm apart from the upper end 32 of phase mask plate.The focal length of first convergent lens 21 is 30mm; The focal length of first divergent lens 22 is 20mm; The focal length of offset lens 25 is 50mm; Distance between first convergent lens 21 and first divergent lens 22 is 10mm, first divergent lens 22 to and offset lens 25 between distance be 30mm, offset lens 25 is 500mm with the distance of phase mask plate 3.

The wavelength of the triangle grating that the described producing device of present embodiment is produced is 1555nm.

Embodiment four

Present embodiment combines accompanying drawing 4 to further specify.

A kind of triangle grating producing device that adopts two convergent lenses and two divergent lens composition expansion speed systems, as shown in Figure 4.

This producing device comprises: excimer laser 1, first convergent lens 21 and first divergent lens 22, second convergent lens 23 and second expansion speed system 2, phase mask plate 3, the optical fiber 4 that convergent lens 24 is formed.

Excimer laser 1 is as writing light source; Lens are put order and are first convergent lens 21, first divergent lens 22, second convergent lens 23, second convergent lens 24 in the expansion speed system 2; Expansion speed system 2 places perpendicular to primary optical axis, and phase mask plate 3 is 45 with primary optical axis, and makes the center downward bias of phase mask plate 3 leave primary optical axis 128mm; Optical fiber 4 is placed perpendicular to primary optical axis, and the upper end 42 that makes optical fiber is 15mm apart from the upper end 32 of phase mask plate.The focal length of first convergent lens 21 is 40mm; The focal length of first divergent lens 22 is 10mm; The focal length of second convergent lens 23 is 50mm; The focal length of second divergent lens 24 is 5mm, and the distance between first convergent lens 21 and first divergent lens 22 is 30mm, and the distance between first divergent lens 22 and second convergent lens is 10mm; Distance between second convergent lens 23 and second divergent lens 24 is 55mm, and the distance of second divergent lens and phase mask plate 3 is 1000mm.

The wavelength of the triangle grating that the described producing device of present embodiment is produced is 1575nm.

Distance between phase mask plate 3 and the optical fiber 4 is the distance of the upper end 32 of phase mask plate to the upper end 42 of optical fiber; That part of part that can shine for light beam of optical fiber 4 exposure.

The employed device of the utility model is commercially available device.

Claims

1. triangle grating producing device, it comprises laser instrument, phase mask plate, optical fiber, optical fiber and phase mask plate are 0 °～45 ° placements, it is characterized in that:

Laser instrument adopts excimer laser, between excimer laser (1) and phase mask plate (3), establishes an expansion speed system (2); Expansion speed system (2) places perpendicular to primary optical axis.

2. a kind of triangle grating producing device according to claim 1 is characterized in that:

Described expansion speed system (2) comprises first convergent lens (21) and first divergent lens (22) that order is placed; Phase mask plate (3) is placed perpendicular to primary optical axis, and its center is just in time on primary optical axis; The upper end of optical fiber (42) is close to the upper end (32) of phase mask plate and is placed; The first half of expansion speed system (2) covers the ultraviolet light beam that excimer laser (1) is launched with black cloth (5).

3. a kind of triangle grating producing device according to claim 1 is characterized in that: expansion speed system (2) comprises first convergent lens (21), second convergent lens (23) that order is placed; Phase mask plate (3) is placed perpendicular to primary optical axis, and wherein departs from primary optical axis 5mm～128mm on the mind-set; The upper end of optical fiber (42) is apart from upper end (32) 5mm～15mm of phase mask plate.

4. a kind of triangle grating producing device according to claim 1 is characterized in that: expansion speed system (2) comprises first convergent lens (21), first divergent lens (22) and the offset lens (25) that order is placed; Phase mask plate (3) is 0 °～45 with primary optical axis, and makes the center downward bias of phase mask plate (3) leave primary optical axis 5mm～128mm; Optical fiber (4) is placed perpendicular to primary optical axis, and makes upper end (32) 5mm～15mm of the upper end (42) of optical fiber apart from phase mask plate.

5. a kind of triangle grating producing device according to claim 1 is characterized in that: expansion speed system (2) comprises first convergent lens (21), first divergent lens (22), second convergent lens (23) and second divergent lens (24) that order is placed; Phase mask plate (3) is 0 °～45 with primary optical axis, and makes phase mask plate (3) center downward bias from primary optical axis 5mm～128mm; Optical fiber (4) is placed perpendicular to primary optical axis, and makes upper end (32) 5mm～15mm of the upper end (42) of optical fiber apart from phase mask plate.