CN201464669U - Interference type fine-core optical fiber wave filter - Google Patents
Interference type fine-core optical fiber wave filter Download PDFInfo
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- CN201464669U CN201464669U CN2009201249389U CN200920124938U CN201464669U CN 201464669 U CN201464669 U CN 201464669U CN 2009201249389 U CN2009201249389 U CN 2009201249389U CN 200920124938 U CN200920124938 U CN 200920124938U CN 201464669 U CN201464669 U CN 201464669U
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Abstract
The utility model relates to an interference type fine-core optical fiber wave filter. The traditional optical fiber grating wave filter is not suitable for running under extreme working conditions due to poor temperature stability. The interference type fine-core optical fiber wave filter comprises an encapsulating box. An SMF (single mode fiber) assembly penetrates through the encapsulating box, and the two ends of the SMF assembly are respectively connected with a flange. The SMF assembly comprises three SMFs connected in series, the SMFs at the two ends are standard, the SMF in the middle adopts a fine core, the three SMFs are coaxially arranged, and the two ends of the fine-core SMF are respectively fused with one end of the two standard SMFs. The interference type fine-core optical fiber wave filter has the characteristics that the wave filter is simple for manufacturing, has good temperature stability and can respond to the changing of the external refraction rate.
Description
Technical field
The utility model belongs to the optical fiber technology field, relates to a kind of interfere type thin-core fibers wave filter.
Background technology
Optical fibre device is because advantages such as little, the light weight of volume, simple in structure, anti-electromagnetic interference (EMI) have obtained application widely in fields such as communication, sensings.Especially the wave filter of full fiber type, its performance direct relation is the transmission quality of Networks of Fiber Communications till now.Wherein, fiber grating is now at the wave filter of using the most ripe a kind of optical-fiber type, and it is divided into two kinds: a kind of be called Fiber Bragg Grating FBG (Fiber BraggGrating, FBG), it is a kind of reflection-type bandpass filter of arrowband; Another kind is called long period fiber grating, and (Long Period Fiber Grating, LPG), it is a kind of transmission-type rejection filter.Though these two kinds of wave filter structures are relatively simple, rejection ratio is also than higher, and temperature stability is not fine, especially long period fiber grating, more responsive to temperature, temperature-responsive is approximately 0.1～0.3nm/ ℃, and this has influenced it greatly as stability of filter.In addition, fiber grating will begin to degenerate in greater than 300 ℃ environment, does not therefore utilize it to move under extreme condition of work.
No matter the optical fibre device of non-optical grating construction is as wave filter or Application in Sensing, is better than grating class device on its thermal stability and the manufacture difficulty mostly, has attracted many scholars' sight in recent years in the world, becomes the focus of research.The direction of many researchs is exactly the design of optical fiber internal interference instrument, utilizes its interference pattern to realize the application of filtering or sensing detection.The design philosophy that this class device is general all is to utilize the special construction in the optical fiber to excite the higher order mode that transmits light, causes the light of different mode having different optical path differences later on through same fiber lengths.But some design proposal often has complicated step in manufacturing process, such as connecing a bit of multimode optical fiber, or utilizes means such as heating to make technology such as fiber end face place fibre core expansion, has all increased the manufacture difficulty of device; Some needs special material, and such as using some extraordinary doubly clad optical fibers, photonic crystal fiber etc., cost are quite high; Having is exactly the non-constant of physical strength of some structures again, such as draw awl to realize the structure that higher order mode excites by optical fiber, does not almost have practical value.
Summary of the invention
The purpose of this utility model just provides a kind of optical fiber filter based on different core diameter single-mode fused fiber splice structures, this wave filter utilizes the optical fiber core diameter mismatch at fused fiber splice place, cause that higher order mode excites, thereby the Mach-Zehnder interferometer in the optical fiber that forms, the spectrum of its transmission has good bandreject filtering characteristic.
The utility model comprises enclosure, and the single-mode fiber assembly passes the enclosure setting, and the two ends of single-mode fiber assembly are connected with ring flange respectively.Described single-mode fiber assembly comprises three section single-mould fibers of series connection, wherein the single-mode fiber at two ends adopts standard single-mode fiber (Corning SMF28, core diameter 6.06 μ m), the interlude single-mode fiber adopts thin core single-mode fiber (Nufern 460-HP, core diameter 3.30 μ m, cutoff wavelength 450nm), the coaxial setting of three section single-mould fibers, the two ends of thin core single-mode fiber respectively with an end welding of two segment standard single-mode fibers.
Principle of work of the present utility model: light is single mode transport in first section single-mould fiber, the basic mode that only has the sandwich layer transmission. behind one section thin-core fibers in the middle of light imports into, because fibre core varies in size, cause light single mode transport again, the pattern of one even a plurality of high-orders is excited out. and since different patterns when in optical fiber, transmitting effective refractive index be different, therefore, when arriving another section single-mould fiber, the light of different mode can have optical path difference, will produce interference then, the form of Here it is Mach-Zehnder interferometer. its interference pattern has promptly been represented the filtering characteristic of wave filter, the rejection ratio of filtering is with to interfere contrast directly related. by being various patterns under the different core diameters radially to be distributed to simulate obtain: at first, the mode field diameter of the single-mode fiber basic mode of different core diameters is different, this provides necessary condition for exciting of higher order mode. secondly, the higher order mode of even does not have power transfer at sandwich layer. and last, optical fiber for thin core, the energy relative standard single-mode fiber of the sandwich layer part that odd order modes comprises is a lot of less, therefore, interior basic mode of sandwich layer and high-order mode energy are approaching when interfering, therefore interfere good contrast, because higher order mode covering energy loss is few, the insertion loss of this wave filter is also very little in addition.
The utility model is made very simple, only needs two kinds of single-mode fibers of a unjacketed optical fiber welder and different core diameters.The interior Mach-Zehnder interferometer of optical fiber that the utility model utilizes the mutual welding of the optical fiber of different core diameters to realize, the interference pattern of the transmission-type of this interferometer presents low Insertion Loss, the filtering characteristic of high rejection ratio.The utlity model has the good temperature stability and the response characteristic of variations in refractive index to external world.
Description of drawings
Fig. 1 is the structural representation of the utility model median filter;
Fig. 2 is that wave filter is to the temperature-responsive spectral line;
Fig. 3 is a wave filter refractive index response spectral line to external world.
Embodiment
As shown in Figure 1, interfere type thin-core fibers wave filter comprises enclosure 3, and the single-mode fiber assembly passes enclosure 3 and is provided with, and the two ends of single-mode fiber assembly are connected with ring flange 1 respectively.Described single-mode fiber assembly comprises three section single-mould fibers of series connection, wherein the single-mode fiber at two ends adopts standard single-mode fiber 2 (CorningSMF28, core diameter 6.06 μ m), the interlude single-mode fiber adopts thin core single-mode fiber 4 (Nufern 460-HP, core diameter 3.30 μ m, cutoff wavelength 450nm), the coaxial setting of three section single-mould fibers, the two ends of thin core single-mode fiber 4 respectively with an end welding of two segment standard single-mode fibers 2.This wave filter links to each other with spectrometer with wideband light source respectively with other wire jumpers prolongations by ring flange, and it is exactly that light source light spectrum is through the filtered transmission spectrum of wave filter that spectrometer obtains.
A very important index of wave filter during temperature-responsive is directly connected to the stability of its work.As can be seen from Figure 2, the position of interference peaks centre wavelength is along with the rising of temperature is drifted about to the long wave direction, and both present a good linear relationship.Calculate the slope of this straight line, obtain the temperature-responsive sensitivity of wave filter, be 15pm/ ℃, the temperature stability that this wave filter is described is goodish.
In addition, because the effective refractive index of the higher order mode that excites transmission is subjected to the influence of extraneous refractive index, so this wave filter utilizes the drift of its centre wavelength also to can be used as sensing applications.This wave filter has carried out the test of refractive index to the sucrose solution of variable concentrations, and (mass percent is respectively: (1.381,5.123,8.425,11.817,14.821,18.033,21.136,24.242,26.901,29.577,32.432,35.065; Corresponding refractive index is 1.3346,1.3400,1.3448,1.3500,1.3547,1.3599,1.3651,1.3704,1.3750,1.3798,1.3850,1.3899), can see, its to external world variations in refractive index be quite responsive, sensitivity reaches 135.5/ unit refractive index, sees Fig. 3.And within a large range, the drift of variations in refractive index and centre wavelength is a linear relationship, and therefore this wave filter has the very big potentiality as Application in Sensing.
Claims (1)
1. interfere type thin-core fibers wave filter comprises enclosure, it is characterized in that: the single-mode fiber assembly passes the enclosure setting, and the two ends of single-mode fiber assembly are connected with ring flange respectively; Described single-mode fiber assembly comprises three section single-mould fibers of series connection, wherein the single-mode fiber at two ends adopts standard single-mode fiber, the interlude single-mode fiber adopts thin core single-mode fiber, the coaxial setting of three section single-mould fibers, the two ends of thin core single-mode fiber respectively with an end welding of two segment standard single-mode fibers; Described standard single-mode fiber adopts the CorningSMF28 single-mode fiber, and described thin core single-mode fiber adopts Nufern 460-HP single-mode fiber.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2009201249389U CN201464669U (en) | 2009-07-21 | 2009-07-21 | Interference type fine-core optical fiber wave filter |
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| Application Number | Priority Date | Filing Date | Title |
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| CN2009201249389U CN201464669U (en) | 2009-07-21 | 2009-07-21 | Interference type fine-core optical fiber wave filter |
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| CN201464669U true CN201464669U (en) | 2010-05-12 |
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| CN2009201249389U Expired - Lifetime CN201464669U (en) | 2009-07-21 | 2009-07-21 | Interference type fine-core optical fiber wave filter |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101604048B (en) * | 2009-07-21 | 2012-02-01 | 浙江大学 | All-fiber filter based on thin-core fibers |
| CN103969221A (en) * | 2013-01-25 | 2014-08-06 | 中国计量学院 | Optical fiber refractive index sensor based on single mode-fine core-multimode-single mode structure |
| CN105259117A (en) * | 2015-08-14 | 2016-01-20 | 江苏双仪光学器材有限公司 | Mode interference-based fine core cascaded optical fiber biosensor |
-
2009
- 2009-07-21 CN CN2009201249389U patent/CN201464669U/en not_active Expired - Lifetime
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101604048B (en) * | 2009-07-21 | 2012-02-01 | 浙江大学 | All-fiber filter based on thin-core fibers |
| CN103969221A (en) * | 2013-01-25 | 2014-08-06 | 中国计量学院 | Optical fiber refractive index sensor based on single mode-fine core-multimode-single mode structure |
| CN105259117A (en) * | 2015-08-14 | 2016-01-20 | 江苏双仪光学器材有限公司 | Mode interference-based fine core cascaded optical fiber biosensor |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| AV01 | Patent right actively abandoned |
Granted publication date: 20100512 Effective date of abandoning: 20090721 |