CN1632625A - Single fiber three-way depolarizing cut off filter - Google Patents
Single fiber three-way depolarizing cut off filter Download PDFInfo
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- CN1632625A CN1632625A CNA2004100777755A CN200410077775A CN1632625A CN 1632625 A CN1632625 A CN 1632625A CN A2004100777755 A CNA2004100777755 A CN A2004100777755A CN 200410077775 A CN200410077775 A CN 200410077775A CN 1632625 A CN1632625 A CN 1632625A
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- 239000000835 fiber Substances 0.000 title claims abstract description 16
- 230000002999 depolarising effect Effects 0.000 title claims description 8
- 239000000463 material Substances 0.000 claims abstract description 12
- 238000000576 coating method Methods 0.000 claims abstract description 6
- 238000007747 plating Methods 0.000 claims description 8
- 239000000758 substrate Substances 0.000 claims description 8
- 230000008878 coupling Effects 0.000 claims description 6
- 238000010168 coupling process Methods 0.000 claims description 6
- 238000005859 coupling reaction Methods 0.000 claims description 6
- 229910004298 SiO 2 Inorganic materials 0.000 claims description 3
- 238000013461 design Methods 0.000 abstract description 7
- 238000004891 communication Methods 0.000 abstract description 4
- 239000011248 coating agent Substances 0.000 abstract 2
- 230000003287 optical effect Effects 0.000 description 53
- 239000010408 film Substances 0.000 description 25
- 230000010287 polarization Effects 0.000 description 13
- 230000028161 membrane depolarization Effects 0.000 description 12
- 238000000926 separation method Methods 0.000 description 7
- 230000005540 biological transmission Effects 0.000 description 5
- 238000005516 engineering process Methods 0.000 description 5
- 238000003780 insertion Methods 0.000 description 5
- 230000037431 insertion Effects 0.000 description 5
- 238000004364 calculation method Methods 0.000 description 3
- 238000002834 transmittance Methods 0.000 description 3
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 2
- 230000015572 biosynthetic process Effects 0.000 description 2
- 235000013399 edible fruits Nutrition 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000000034 method Methods 0.000 description 2
- 238000005457 optimization Methods 0.000 description 2
- 238000009738 saturating Methods 0.000 description 2
- 230000003595 spectral effect Effects 0.000 description 2
- 239000010409 thin film Substances 0.000 description 2
- 238000012546 transfer Methods 0.000 description 2
- 229910052681 coesite Inorganic materials 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 229910052906 cristobalite Inorganic materials 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
- 238000009795 derivation Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 239000011521 glass Substances 0.000 description 1
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- 238000002955 isolation Methods 0.000 description 1
- 239000011159 matrix material Substances 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 239000013307 optical fiber Substances 0.000 description 1
- 230000000737 periodic effect Effects 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 238000002310 reflectometry Methods 0.000 description 1
- 239000000377 silicon dioxide Substances 0.000 description 1
- 235000012239 silicon dioxide Nutrition 0.000 description 1
- 238000001228 spectrum Methods 0.000 description 1
- 229910052682 stishovite Inorganic materials 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
- PBCFLUZVCVVTBY-UHFFFAOYSA-N tantalum pentoxide Inorganic materials O=[Ta](=O)O[Ta](=O)=O PBCFLUZVCVVTBY-UHFFFAOYSA-N 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
- 229910052905 tridymite Inorganic materials 0.000 description 1
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Abstract
This invention relates to fiber communication optics filter and is aimed to design a single fiber with three direction polarization-removing close filter, which comprises the base pad and coating film. The film structure of the coating film is G|2H{0.5L(HL)#+[3]0.13H(LH)#+[3] 0.5L}#+[4](2.38H)#+[1](1.41L)#+[1]|A, wherein, the central wavelength is 1590nm and the low reflection material is SiO#-[2] and the high reflection material is Ta#-[2]O#-[5] where G represents base pad; A for air; 3 or 4 for circle number; 0.13 for disorder element; 0.5 for one quarter of central wavelength of 0.5 optics thickness.
Description
Technical field
The present invention relates to the optical filter field in the optical-fibre communications field, a kind of single fiber three-way depolarizing cut off filter of saying so more specifically.
Technical background
Along with the rise of user terminal video program request, ecommerce, novel business such as end-to-end, then inevitable requirement is carried out integrated audio frequency, video, data transmission at user side.The single fiber three-way technology is one of major technique that realizes at the optical access network of EPON (PON) (OAN) audio frequency, video, data integration transmission, is the optical communication technology focus of developing in the world at present.Emphasis is that the three-dimensional partial wave of an optical access network single fiber closes ripple, light signal is sent to ONT Optical Network Terminal (ONT) from optical line terminal (OLT) in the prior art, 1490nm wave band carry data signals wherein, 1550nm carries cable TV signal, 1310nm carries up feedback signal, requires in ONT Optical Network Terminal (ONT) these three wave bands to be realized that partial wave closes ripple.
General technology is to realize the wavelength-division multiplex of EPON with optical thin film.Realize that by three optical filters it is 45 degree that the separation of the light of different wave length, the receiver module of optical access network system require the angle of incidence of light degree of these three optical filters.And the oblique incidence meeting causes the characteristic generation of S polarized light and P polarized light to separate, and causes natural light unsmooth, not precipitous to this section of rest position curve from the passband position.Particularly to the 1st three partial wave optical filters, the 1500nm at the 1540nm at rest position edge and edge, passband position is only at a distance of 40nm when 45 ° of wide-angle incident, the spectral characteristic of optical filter is except satisfying optical access network system to the requirements such as Insertion Loss, isolation, also want the special requirement transmittance curve very steep, so the preparation difficulty of this piece optical filter will be far above the 2nd and the 3rd traditional optical filter.At present have only the optical filter supplier of only a few can produce this three partial waves optical filter both at home and abroad, but the polarization that generally also exists S component and P component rest position not to overlap end separation problem, has influenced the stability of optical filter Polarization Dependent Loss.
Summary of the invention
The objective of the invention is to overcome the shortcoming of prior art, design and a kind ofly can satisfy that transmittance curve is very precipitous, Insertion Loss is low, eliminate the single fiber three-way depolarizing cut off filter of polarization influence.
The present invention is achieved through the following technical solutions its goal of the invention.
The invention provides a kind of single fiber three-way depolarizing cut off filter, comprise substrate and coatings, the film structure of coatings is: G|{0.5L (HL)
^30.13 H (LH)
^30.5L}
^4| A, wherein low refractive material is SiO
2, high-index material is Ta
2O
5, G represents substrate, and A represents air, and ^3 or ^4 represent periodicity, and 0.13 has represented optical thickness for the imbalance factor, 0.5 is individual 1/4th centre wavelengths O.5, centre wavelength is 1590nm.
Adopt the most wavestrip pass filters of rectangle can prepare narrow bandwidth, high-transmission rate and the dark optical filter that suppresses, its basic structure is:
G|[(HL)
S1?H?2mL?H(LH)
S1?L]
S2|G (1)
G represents substrate in the formula, S
2Be periodicity, S
1Be that main film is the number of plies, m is an order of interference.
(1) formula basic structure is modified as:
G|[0.5L(HL)
S1ρH(LH)
S1?0.5L]
S2|G (2)
During imbalance factor ρ=2m is exactly general cutoff filter, and their P components when the light oblique incidence separate with the S component, the formation polarization.When ρ ≠ 2m, just can obtain the cutoff filter of depolarization.The ρ value is the key parameter of depolarization cutoff filter design, can calculate S by setting ρ=2m earlier
1, S
2, and then go out ρ by the calculation of parameter of boundary condition, the high-index material of selecting for use and low-index material.
For improving the transmitance of light 1490 ± 10nm, by computer optimization, add plating coupling film in main film system, caudacoria binds fruit and is:
G|2H{0.5L(HL)
^3?0.13?H(LH)
^3?0.5L}
^4(2.38H)
^1(1.41L)
^1|A
The film structure of coupling film is that the outside adds plating (2.38H) for add plating 2H between substrate and main film system at main film
^1(1.41L)
^1
The present invention has following outstanding substantive distinguishing features and obvious improvement with respect to prior art:
1. the characteristics that adopt the optical filter of this film structure can possess narrow bandwidth, high-transmission rate simultaneously, suppress and can depolarization end deeply;
2. film structure of the present invention has overcome S component and P component rest position do not overlap under wide-angle incident polarization by separation problem, has eliminated the polarization separation influence.
3. be a kind of optical filter that ends at 45 depolarizations of spending polarized component rest position coincidence under the incidents, transmittance curve is precipitous, Insertion Loss is low, eliminates the polarization separation influence, has satisfied the requirement of optical access network single fiber three-way system;
4. the present invention adds the cooperation of other two optical filters, make device that these three optical filters constitute can be well at the optical information of this section of Access Network fiber-to-the-home realization uplink 1490nm, 1550nm wave band, and downlink transfer 1310nm wave band light wave is as feedback information, in the optical line terminal that can be widely used in spreading out in the optical access network construction, the ONT Optical Network Terminal.
Description of drawings
Fig. 1 closes the ripple synoptic diagram for the present invention is incorporated in optical access network system single fiber three-way partial wave;
Fig. 2 is the Insertion Loss curve map of Theoretical Calculation of the present invention;
The actual Insertion Loss curve map that records of Fig. 3 the present invention.
Embodiment
The present invention is described further below in conjunction with accompanying drawing.
Optical access network (OAN) single fiber three-way technology is to realize one of fiber-to-the-home major technique, is the optical communication technology focus of developing in the world at present.In the optical access network single fiber three-way system, it is the key factor that restricting channel separates that wide-angle incident causes the polarized light division.As shown in Figure 1, two transmission window 1550nm of the descending employing of passive optical access network and 1490nm carry analog catv signal and data-signal respectively, up employing 1310nm window wavelength.Therefore EPON needs wavelength division multiplexer that the wavelength of these three transmission windows is carried out wave splitting/composing at optical line terminal (OLT), ONT Optical Network Terminal (ONT).General system all adopts optical filter to realize the wavelength-division multiplex of EPON: the light of optical filter 1 high saturating 1490nm wavelength, and the light of high anti-1310,1550nm wavelength; The light of optical filter 2 high saturating 1550nm wavelength, and the light of high anti-1310nm wavelength; The light of optical filter 3 high anti-1550nm wavelength.It is 45 degree that the receiver module of optical access network system requires the angle of incidence of light degree of these three optical filters.
The present invention uses the optical thin film depolarization by principle, design has also been developed a kind of single fiber three-way depolarizing cut off filter as optical filter 1, overcome and under wide-angle incident, to have ended separation problem with the polarization that P component rest position does not overlap by the S component, eliminated the polarization separation influence.The principle of the present invention's design is as follows:
During imbalance factor ρ in above-mentioned formula (2)=2m is exactly general cutoff filter, and the P component separates with the S component when the light oblique incidence, the formation polarization.When ρ ≠ 2m, just can obtain the cutoff filter of depolarization.Therefore the ρ value is the key parameter of depolarization cutoff filter design, below the derivation of equation is carried out in the calculating of ρ value.
The structure of formula (2) also can be write as
G|[(0.5L?H?0.5L)
S1(0.5LρH?0.5L)(0.5L?H?0.5L)
S1]
S2|G (3)
The periodicity film system that formula (3) is made up of three seriess of symmetrical film is because series of symmetrical film a
1A
1a
2A
2... a
nA
n... a
2A
2a
1A
1Eigenmatrix and the eigenmatrix of monofilm have same nature, on mathematics, can equivalence be monofilm
[8], according to the interference matrix of formula (3) film system be:
Wherein
Equivalence position phase thickness d=pg/2 in the formula, wave number g=λ/λ
0, λ
0Be centre wavelength, η
HAnd η
LThe equivalent refractive index of representing H, L material respectively.
Abbreviation formula (4) can get
When | M
11|>1 o'clock, equivalent optical admittance was an imaginary number, and an equivalence position phase thickness is a plural number, expression be the Gao Fanqu of film system; When | M
11|<1 o'clock, equivalent optical admittance and equivalence position phase thickness all were real numbers, corresponding to the transmission band of film system; | M
11|=1 corresponding film is a rest position, and two films are that depolarization point must corresponding two films be that rest position overlaps.
Therefore according to formula (6), as selected S
1, S
2After the value, M
11It only is the function of ρ and g.When oblique incidence,, have respectively in rest position to S, P component:
Eliminate polarization, even two polarized component rest position overlap, at this moment
g
s=g
p (8)
Can obtain separating of ρ value to (8) formula substitution system of equations (7), this ρ value is the value of gained when satisfying the coincidence of two polarized component rest position (one-sided).
For first ripple optical filter, see Fig. 1, make separating of 1490nm light wave and 1550nm and 1310nm two light waves, can realize with the depolarization cutoff filter of periodic symmetry film system imbalance Center Gap layer.The present invention adopts Ta2O5 as high-index material, and SiO2 as low refractive material is, require 1490 ± 10nm transmissivity greater than the reflectivity of 95%, 1310 ± 50nm and 1550 ± 10nm greater than 99% (20db), according to passband width with by the definite S of degree
1Be 3 and S
2After being 4, it is 0.13 that the utilization depolarization solves the ρ value by principle.
For improving the transmitance of light 1490 ± 10nm, by computer optimization, add plating coupling film in main film system, caudacoria binds fruit and is:
G|2H{0.5L (HL)
^30.13H (LH)
^30.5L}
^4(2.38H)
^1(1.41L)
^1| A, n
H=2.065, n
L=1.465, centre wavelength is 1590nm, and the theoretical spectral characteristic under 45 degree incidents as shown in Figure 2.
Adopt this film structure to carry out plated film on the plated film machine of the precious APS1104 of Lay, high low-index material is chosen Ta
2O
5And SiO
2, substrate uses K9 glass, and supervisory wavelength is 1590nm.With institute's plating sample Lamda900 spectrophotometer measurement, test angle is 45 degree, measures the spectrum of S, P light respectively, as shown in Figure 3.As seen, the S component of the sample that plates overlaps substantially with the rest position of P component between 1490~1550nm, reaches depolarization by effect.
This rest position polarization is by fractional dose
Δ λ=| λ
ES-λ
EP|=3.6nm, and polarization by the Theoretical Calculation result of fractional dose is:
Δλ=|λ
ES-λ
EP|=3.8nm。Experimental result and notional result are approaching.
Therefore, the sample that is coated with has proved that the depolarization of this paper is remarkable by design effect, can be applied in the passive optical access network.This piece optical filter adds the cooperation of other two optical filters, make device that these three optical filters constitute can be well at the optical information of this section of Access Network fiber-to-the-home realization uplink 1490nm, 1550nm wave band, and downlink transfer 1310nm wave band light wave is as feedback information.
Claims (2)
1. a single fiber three-way depolarizing cut off filter comprises substrate and coatings, it is characterized in that the film structure of coatings is:
G|{0.5L(HL)
^3?0.13H(LH)
^3?0.5L}
^4|A
Wherein low refractive material L is SiO
2, high-index material H is Ta
2O
5, G represents substrate, and A represents air, { 0.5L (HL)
^30.13H (LH)
^30.5L}
^4Be that main film is, centre wavelength is 1590nm.
2. single fiber three-way depolarizing cut off filter according to claim 1 is characterized in that fastening the coupling film that also is coated with passband ripple cancellation at main film, and the film structure that adds behind the plating coupling film is:
G|2H{0.5L(HL)
^3?0.13H(LH)
^3?0.5L}
^4(2.38H)
^1(1.41L)
^1|A
The film structure of coupling film is that the outside adds plating (2.38H) for add plating 2H between substrate and main film system at main film
^1(1.41L)
^1
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CNB2004100777755A CN1310044C (en) | 2004-12-30 | 2004-12-30 | Single fiber three-way depolarizing cut off filter |
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CNB2004100777755A CN1310044C (en) | 2004-12-30 | 2004-12-30 | Single fiber three-way depolarizing cut off filter |
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Publication Number | Publication Date |
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CN1632625A true CN1632625A (en) | 2005-06-29 |
CN1310044C CN1310044C (en) | 2007-04-11 |
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Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN100414333C (en) * | 2006-07-07 | 2008-08-27 | 中山大学 | A single fiber three-way wave separator/wave combination device |
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KR0171844B1 (en) * | 1995-11-10 | 1999-05-01 | 김광호 | Optical connector using ball lens and producing process thereof |
JPH1048459A (en) * | 1996-07-30 | 1998-02-20 | Seiko Giken:Kk | Optical device and two-way communications system |
US6301420B1 (en) * | 1998-05-01 | 2001-10-09 | The Secretary Of State For Defence In Her Britannic Majesty's Government Of The United Kingdom Of Great Britain And Northern Ireland | Multicore optical fibre |
US6400862B1 (en) * | 2000-05-23 | 2002-06-04 | Alliance Fiber Optics Products, Inc. | Retro-reflective multi-port filter device with triple-fiber ferrule |
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- 2004-12-30 CN CNB2004100777755A patent/CN1310044C/en not_active Expired - Fee Related
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN100414333C (en) * | 2006-07-07 | 2008-08-27 | 中山大学 | A single fiber three-way wave separator/wave combination device |
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Granted publication date: 20070411 Termination date: 20121230 |