CN201662630U - Fiber grating passive temperature compensation wrapper - Google Patents

Abstract

The utility model discloses a fiber grating passive temperature compensation wrapper. An inner bush is embedded in a base, an outer bush is embedded between the inner bush and the base, the outer bush is closed contacted with the inner bush, and a clearance is formed between the outer bush and the base. Fiber gratings are respectively bonded on the inner bush and the base through epoxy glue. Screwed holes are arranged at the bottom or the side of the base; adjusting bolts for adjusting the wavelength of the fiber gratings are put through the screwed holes and pushed on the bottom or side of the outer bush in an adjustable way. The inner bush and the outer bush, the outer bush and the base are respectively welded by laser or bonded by glue. The periphery of the outer bush is a stepped structure, thereby a clearance is formed between the periphery of the outer bush and the base. The screwed holes are arranged on the base, in particular, at the positions with clearance between the base and the outer bush. The utility model prevents the fiber gratings from bending and realizes bidirectional regulation from center wavelength to long wave or short wave; the connection between the inner bush and the outer bush, and between the outer bush and the base is high in strength and long in service life and the surfaces of the connection points looks good.

Description

Fiber grating passive temperature compensation wrapper

Technical field

The utility model relate to a kind of in optical fiber telecommunications system employed fiber grating, particularly relate to a kind of passive encapsulation of fiber grating and fiber grating passive temperature compensation wrapper of wavelength tuning of being used for.

Background technology

Fiber grating is widely used in the system of optical fiber communication.For example: Wavelength division multiplexer/demultiplexer, Distributed Feedback Laser, EDFA gain flattening filter, dispersion compensator etc.In actual use, the temperature of environment can change.When environment temperature changes, the effective refractive index of fiber grating and cycle understand the change of Yin Wendu and change, according to the relation of centre wavelength and effective refractive index as can be known the centre wavelength of fiber grating also can produce drift, the size of drift is about 10pm/ ℃, both are linear.The size of this wave length shift is unacceptable in the practical application in fibre system, so need carry out the encapsulation of temperature compensation to fiber grating.

The characteristic of the temperature of fiber grating and stress changes centre wavelength of being based on Chinese patent 02278787.9 designs, a kind of structure that it utilizes two kinds of different materials of expansion coefficient to constitute.This structure applies certain stress in advance to fiber grating earlier, carry out a glue encapsulation then, when temperature raises or reduce, the centre wavelength of fiber grating can be drifted about toward long wave or shortwave, and the stress at fiber grating two ends can reduce or increase, the centre wavelength of impelling fiber grating again is toward shortwave or long wave drift, and when the two drift size is consistent, the centre wavelength of fiber grating will can not drifted about.This patent provides the fiber grating encapsulating structure of the little foldable structure of a kind of volume, and its shortcoming is: after the encapsulation, can not regulate the centre wavelength of fiber grating.

When the fiber grating two ends are applied certain external force, certain deformation will take place in fiber grating, and the deformation of output is evenly distributed on above the optical fiber, and the cycle of grating also changes thereupon, corresponding corresponding the changing of centre wavelength.Also can make the wherein living change of cardiac wave long hair so change the effective length of fiber grating.Patent US006907164B2 provides a kind of no source temperature encapsulating structure of wavelength-tunable, one end of this structure is designed to helicitic texture, rotation by screw thread can change the stress intensity that puts on the fiber grating two ends, has changed the effective length of fiber grating, thereby plays the wavelength regulation effect.Utilize screw thread to regulate the stress at fiber grating two ends, because the pitch precision of screw thread own is certain, carry out the accuracy rating that axial adjustment also can only reach 10 micron number magnitudes by the rotation screw thread, and according to this Structure Calculation, when axial elongation or when shortening 10 microns, centre wavelength is drifted about more than 100 micromicrons toward long wave or shortwave, so be subjected to the restriction of physical construction, the centre wavelength degree of regulation of this patent is limited.

Chinese patent 200710178617.2 provides a kind of passive packaged type of wavelength-tunable of urging of more stepping up.Describe according to this patent, fiber grating is encapsulated on two tie points, and grating is wrapped in above the unsteady regulating block, the position by regulating two tie points or the position of unsteady regulating block, can regulate the effective length of fiber grating, thus the adjusting of realization wavelength.This patent has the problem of wavelength regulation precision equally.And grating is that bending is wrapped in above the unsteady regulating block in this structure, and grating is annealed in the actual process, and the grating of annealed processing will become fragile, frangibility very after the bending.

Summary of the invention

Technical problem to be solved in the utility model is that a kind of fiber grating passive temperature compensation wrapper with high precision wavelength regulation is provided.

The technical scheme that the utility model adopted is: a kind of fiber grating passive temperature compensation wrapper, include fiber grating, neck bush, external bushing and base, described neck bush is nested in the base, described external bushing is nested between neck bush and the base, described external bushing and neck bush are for closely to contact, be formed with the gap between external bushing and the base, in described fiber grating is bonded in respectively by epoxy glue village cover and base above, bottom or sidepiece at base have threaded hole, and the set screw that is used to regulate optic fiber grating wavelength is passed adjustable bottom or the sidepiece that withstands on external bushing of threaded hole.

Described neck bush and described external bushing, and adopt laser bonding or gluing connecing between described external bushing and the described base.

The periphery of described external bushing is the notch cuttype structure, thereby is formed with the gap between the periphery of external bushing and the base.

Described threaded hole is arranged on and forms gapped position with external bushing on the base.

Another technical scheme that the utility model adopted is: a kind of fiber grating passive temperature compensation wrapper, include fiber grating, first welding block, second welding block, short lining, long bushing and base, the inside, both sides of described base is hollow structure, the hollow structure of described both sides is communicated with by the through hole that is formed at the base middle part, be nested with first welding block in the hollow structure of described base one side closely, between first welding block and base, be nested with short lining closely with through hole; Be nested with second welding block in the hollow structure of described base opposite side with through hole, between second welding block and base, be nested with long bushing, be formed with the gap between described long bushing and the base, described fiber grating runs through first welding block and second welding block, and is bonded in respectively by epoxy glue in the through hole of first welding block and second welding block; Bottom or sidepiece at base have threaded hole, and described threaded hole is corresponding to long bushing, and the set screw that is used to regulate optic fiber grating wavelength is passed adjustable bottom or the sidepiece that withstands on long bushing of threaded hole.

Between described first welding block and short lining and second welding block and the long bushing is gluing or laser bonding, is gluing or laser bonding between short lining and long bushing and the base.

The periphery of described long bushing is the notch cuttype structure, is formed with the gap thereby make between the periphery of long bushing and the base.

Fiber grating passive temperature compensation wrapper of the present utility model has following characteristics:

1. encapsulating structure form of the present utility model is an axial tension optical fiber, has avoided the bending of grating;

2. when adopting structure wavelength regulation of the present utility model, wavelength regulation is more accurate;

3. by tightening or unclamping screw, can realize that centre wavelength is to long wave or shortwave bidirectional modulation;

4. the connected mode between neck bush and external bushing, external bushing and the base is gluing or laser bonding.This method strength of joint height, long service life, the tie point surface aesthetic.

Description of drawings

Fig. 1 is the wavelength-tunable optical fiber grating wrapper structural representation before the wavelength regulation;

Fig. 2 is the wavelength-tunable optical fiber grating wrapper structural representation after the wavelength regulation;

Fig. 3 is the external bushing structural representation;

Fig. 4 regulates the model synoptic diagram;

Fig. 5 is the preceding wavelength-tunable optical fiber grating wrapper of wavelength regulation of second kind of encapsulating structure;

Fig. 6 is the wavelength-tunable optical fiber grating wrapper after the wavelength regulation of second kind of encapsulating structure.

Wherein:

1: fiber grating 2: solder joint

3: left side epoxy glue point 4: neck bush

5: set screw 6: external bushing

7: base 8: right side epoxy glue point

9: 10: the first welding blocks of short lining

11: left epoxy glue point 12: base

13: right epoxy glue point 14: set screw

Welding block 16 in 15: the second: long bushing

17: fiber grating 18: ladder-type structure

19: threaded hole 20: threaded hole

Embodiment

Provide specific embodiment below in conjunction with accompanying drawing, further specify fiber grating passive temperature compensation wrapper of the present utility model and how to realize.

According to the characteristic of fiber grating strain as can be known: stress causes that the long change of cloth loudspeaker lattice wave is to be realized by the strain that stress produces, promptly

σ＝Eò (1)

σ is a stress in the formula, be act on the fiber grating two end axles to pulling force, E is the Young modulus of optical fiber, ò is strain, is the flexible of the unit length under the stress.Because the effect of stress finally will cause the variation of the effective refractive index and the grating pitch of fiber grating, thereby it is long to change cloth loudspeaker lattice wave.

Strain is to long the changing into of cloth loudspeaker lattice wave

Δλ _Bs＝2(ΛΔn _es+n _effΔΛ _s) (2)

Δ n in the formula _EsBe the variation that fiber grating effective refractive index stress produces, Δ Λ _sBe the variation of fiber grating pitch stress generation, and

$\mathrm{\Δ}{n}_{\mathrm{es}}=-(1/2)n_{\mathrm{eff}}^3[(1-v)P_{12}-v{P}_{11}]\∈---\left(3\right)$

P in the formula ₁₁, P ₁₂Be strain optical coefficient, v is the Poisson ratio of core material, will

ΔΛ _s＝òΛ (4)

Formula (1), formula (3), formula (4) substitution formula (2) and abbreviation can get the relation of the Bragg wavelength that stress causes

$\mathrm{\Δ}{\mathrm{\λ}}_{\mathrm{Bs}}={\mathrm{\λ}}_B\{1-(1/2)n_{\mathrm{eff}}^2[(1-v)P_{12}-P_{11}\left]\right\}\frac{\mathrm{\σ}}{E}---\left(5\right)$

P ₁₁, P ₁₂, v, E be constant, order

$C=\frac{1-(1/2)n_{\mathrm{eff}}^2[(1-v)P_{12}-v{P}_{11}]}{E}---\left(6\right)$

Can get

ΔλB _s＝λ _BCσ (7)

The Bragg wavelength variations and the stress that produce of stress is linear as can be known by following formula.

As shown in Figure 1, fiber grating passive temperature compensation wrapper of the present utility model, be a kind of nested structure, include fiber grating 1, neck bush 4, external bushing 6 and base 7, described neck bush 4 is nested in the base 7, described external bushing 6 is nested between neck bush 4 and the base 7, described external bushing 6 and neck bush 4 are for closely to contact, be formed with the gap between external bushing 6 and the base 7, the gap of reserving is not contact with base 7 inwalls after external bushing 6 distortion in order to guarantee, specific practice is that the periphery with external bushing 6 is designed to have notch cuttype structure 18, thereby is formed with the gap between the periphery of external bushing 6 and the base 7.In described fiber grating 1 is bonded in respectively by epoxy glue village cover 4 and base 7 above, have threaded hole 19 at the bottom or the sidepiece of base 7, described threaded hole 19 is arranged on and forms gapped position with external bushing 6 on the base 7.The set screw 5 that is used to regulate fiber grating 1 wavelength is passed threaded hole 19 adjustable bottom or sidepieces that withstand on external bushing 6.

Described neck bush 4 and described external bushing 6, and adopt laser bonding or gluing connecing between described external bushing 6 and the described base 7.

The principle of work of fiber grating passive temperature compensation wrapper of the present utility model is as follows, and as shown in Figure 2, fiber grating 1 is put 8 by left side epoxy glue point 3 and right side epoxy glue and bondingly is bonded in neck bush 4 respectively and above the base 7.Base 7 bottoms have threaded hole 19, pass threaded hole 19 with a set screw 5 and withstand external bushing 6, when set screw 5 contacts with external bushing 6, utilize the elastic deformation characteristics of material itself, continuing to tune joint commentaries on classics screw 5 up pushes up external bushing 6, because external bushing 6 is to be closely linked with neck bush 4, the bending of external bushing 6 also drives neck bush 4 flexural deformations, finally make left side epoxy glue point 3 produce axial displacement, the displacement of epoxy glue point has changed the effective length of fiber grating 1, thereby reaches the purpose of wavelength regulation.Concrete wavelength regulation amount is provided by corresponding formulas, and external bushing 6 horizontal deformational displacements are transformed into the axial displacement of epoxy glue point will dwindle tens times, and wavelength regulation will be more accurate.

Be described in conjunction with Fig. 3, specific as follows:

L ₁Be the distance between set screw 5 and the solder joint 2, L ₂Be the distance between left side epoxy glue point 3 and the solder joint 2, L ₃Be the distance between left side epoxy glue point 3 and the right side epoxy glue point 8.In adjustment process, the distance of mechanical adjustment set screw 5 is Δ h, and external bushing 6 is under the effect of set screw 5, and the distance that drives left side epoxy glue point 3 and original position variation is

$\mathrm{\&Delta;}{h}^{\&prime;}=\frac{L_2}{{\mathrm{<figure-callout\; id="1"\; label="L"\; filenames="DEST\_PATH\_HDA0000024140770000011.png"\; state="\{\{state\}\}">L</figure-callout>}}_1}\mathrm{\&Delta;h}---\left(8\right)$

Because the position change of left side epoxy glue point 3, cause the distance between left side epoxy glue point 3 and the right side epoxy glue point 8 to change, variable in distance between left side epoxy glue point 3 and the right side epoxy glue point 8 causes fiber grating to produce and stretches, and left side epoxy glue point 3 after the adjusting and the distance between the right side epoxy glue point 8 are

${\mathrm{<figure-callout\; id="3"\; label="L"\; filenames="DEST\_PATH\_HDA0000024140770000011.png,DEST\_PATH\_HDA0000024140770000012.png"\; state="\{\{state\}\}">L</figure-callout>}}_3^{\&prime;}=\sqrt{{\left(\mathrm{\&Delta;}{h}^{\&prime;}\right)}^2+{\mathrm{<figure-callout\; id="3"\; label="L"\; filenames="DEST\_PATH\_HDA0000024140770000011.png,DEST\_PATH\_HDA0000024140770000012.png"\; state="\{\{state\}\}">L</figure-callout>}}_3^2}---\left(9\right)$

The flexible of fiber grating generation is

ΔL＝L′ ₃-L ₃ (10)

With (8) formula, (9) formula substitution (10) formula, can get length variations and be

$\mathrm{\&Delta;L}=\sqrt{{\left(\frac{L_2}{{\mathrm{<figure-callout\; id="1"\; label="L"\; filenames="DEST\_PATH\_HDA0000024140770000011.png"\; state="\{\{state\}\}">L</figure-callout>}}_1}\mathrm{\&Delta;h}\right)}^2+{\mathrm{<figure-callout\; id="3"\; label="L"\; filenames="DEST\_PATH\_HDA0000024140770000011.png,DEST\_PATH\_HDA0000024140770000012.png"\; state="\{\{state\}\}">L</figure-callout>}}_3^2}-L_3---\left(11\right)$

Because Δ L=L ₃, then approximate treatment can get

$\mathrm{\&Delta;L}=\frac{1}{2L_3}{\left(\frac{L_2}{{\mathrm{<figure-callout\; id="1"\; label="L"\; filenames="DEST\_PATH\_HDA0000024140770000011.png"\; state="\{\{state\}\}">L</figure-callout>}}_1}\mathrm{\&Delta;h}\right)}^2---\left(12\right)$

Then wavelength shift is

$\mathrm{\&Delta;}{\mathrm{\&lambda;}}_B=C\frac{{\left(\frac{L_2}{{\mathrm{<figure-callout\; id="1"\; label="L"\; filenames="DEST\_PATH\_HDA0000024140770000011.png"\; state="\{\{state\}\}">L</figure-callout>}}_1}\mathrm{\&Delta;h}\right)}^2}{2{\mathrm{<figure-callout\; id="3"\; label="L"\; filenames="DEST\_PATH\_HDA0000024140770000011.png,DEST\_PATH\_HDA0000024140770000012.png"\; state="\{\{state\}\}">L</figure-callout>}}_3^2}E---\left(13\right)$

So the transversal displacement distance, delta h of set screw 5 just can calculate the variation that fiber grating produces effective length by (11) formula, can be calculated the size of wavelength variations by (13) formula.

By (12) formula as can be known, when the transversely deforming of 6 Δ h of external bushing, the variation that is transformed into the effective length of fiber grating will reduce significantly, thereby realize that wavelength regulates accurately.

In carrying out the wavelength regulation process, fiber grating is connected spectrometer, detect its centre wavelength.The rotation set screw is observed the variation of centre wavelength, and when reaching the wavelength that needs, screw then stops the rotation to centre wavelength.

Utilize screw top external bushing, make it produce elastic deformation, drive a this thinking that the glue point is moved and to be used for other similar encapsulating structures equally.

Fiber grating passive temperature compensation wrapper of the present utility model, can also adopt second kind of structure as described below to constitute:

Include fiber grating 17, first welding block 10, second welding block 15, short lining 9, long bushing 16 and base 12, the inside, both sides of described base 12 is hollow structure, the hollow structure of described both sides is communicated with by the through hole that is formed at base 12 middle parts, be nested with first welding block 10 in the hollow structure of described base 12 1 sides closely, between first welding block 10 and base 12, be nested with short lining 9 closely with through hole; Be nested with second welding block 15 in the hollow structure of described base 12 opposite sides with through hole, between second welding block 15 and base 12, be nested with long bushing 16, be formed with the gap between described long bushing 16 and the base 12, the periphery of described long bushing 16 is the notch cuttype structure, is formed with the gap thereby make between the periphery of long bushing 16 and the base 12.Described fiber grating 17 runs through first welding block 10 and second welding block 15, and is bonded in respectively by epoxy glue in the through hole of first welding block 10 and second welding block 15; Bottom or sidepiece at base 12 have threaded hole 20, and described threaded hole 20 is corresponding to long bushing 16, and the set screw 14 that is used to regulate fiber grating 17 wavelength is passed threaded hole 20 adjustable bottom or sidepieces that withstand on long bushing 16.

Between described first welding block 10 and short lining 9 and second welding block 15 and the long bushing 16 is gluing or laser bonding, is gluing or laser bonding between short lining 9 and long bushing 16 and the base 12.

The wavelength tuning principle of second kind of structure and above-mentioned first kind of structure similar, base 12 bottoms or sidepiece have threaded hole.Set screw 14 is passed threaded hole closedtop assembling structure long bushing 16, when screw 14 with after long bushing 16 contacts, continue rotary screw, impel long bushing 16 to produce elastic deformation, the right epoxy glue point 13 that deformation long bushing 16 drives on the welding block 15 is subjected to displacement, the effective length of fiber grating is changed, thereby reach the wavelength regulation purpose.

Claims (7)

1. fiber grating passive temperature compensation wrapper, include fiber grating (1), neck bush (4), external bushing (6) and base (7), it is characterized in that: described neck bush (4) is nested in the base (7), described external bushing (6) is nested between neck bush (4) and the base (7), described external bushing (6) and neck bush (4) are for closely to contact, be formed with the gap between external bushing (6) and the base (7), in described fiber grating (1) is bonded in respectively by epoxy glue village cover (4) and base (7) above, bottom or sidepiece at base (7) have threaded hole (19), and the set screw (5) that is used to regulate fiber grating (1) wavelength is passed adjustable bottom or the sidepiece that withstands on external bushing (6) of threaded hole (19).

2. fiber grating passive temperature compensation wrapper according to claim 1 is characterized in that, described neck bush (4) and described external bushing (6), and adopt laser bonding or gluing connecing between described external bushing (6) and the described base (7).

3. fiber grating passive temperature compensation wrapper according to claim 1 is characterized in that, the periphery of described external bushing (6) is notch cuttype structure (18), thereby is formed with the gap between the periphery of external bushing (6) and the base (7).

4. fiber grating passive temperature compensation wrapper according to claim 1 is characterized in that, described threaded hole (19) is arranged on and forms gapped position with external bushing (6) on the base (7).

5. fiber grating passive temperature compensation wrapper, include fiber grating (17), first welding block (10), second welding block (15), short lining (9), long bushing (16) and base (12), it is characterized in that, the inside, both sides of described base (12) is hollow structure, the hollow structure of described both sides is communicated with by the through hole that is formed at base (12) middle part, be nested with first welding block (10) in the hollow structure of described base (12) one sides closely, between first welding block (10) and base (12), be nested with short lining (9) closely with through hole; Be nested with second welding block (15) in the hollow structure of described base (12) opposite side with through hole, between second welding block (15) and base (12), be nested with long bushing (16), be formed with the gap between described long bushing (16) and the base (12), described fiber grating (17) runs through first welding block (10) and second welding block (15), and is bonded in respectively by epoxy glue in the through hole of first welding block (10) and second welding block (15); Bottom or sidepiece at base (12) have threaded hole (20), described threaded hole (20) is corresponding to long bushing (16), and the set screw (14) that is used to regulate fiber grating (17) wavelength is passed adjustable bottom or the sidepiece that withstands on long bushing (16) of threaded hole (20).

6. fiber grating passive temperature compensation wrapper according to claim 5, it is characterized in that, between described first welding block (10) and short lining (9) and second welding block (15) and the long bushing (16) is gluing or laser bonding, is gluing or laser bonding between short lining (9) and long bushing (16) and the base (12).

7. fiber grating passive temperature compensation wrapper according to claim 5 is characterized in that the periphery of described long bushing (16) is the notch cuttype structure, is formed with the gap thereby make between the periphery of long bushing (16) and the base (12).

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