CN203894435U - Filtering apparatus for cross wavelength division multiplexing device - Google Patents
Filtering apparatus for cross wavelength division multiplexing device Download PDFInfo
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- CN203894435U CN203894435U CN201420183464.6U CN201420183464U CN203894435U CN 203894435 U CN203894435 U CN 203894435U CN 201420183464 U CN201420183464 U CN 201420183464U CN 203894435 U CN203894435 U CN 203894435U
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- birefringece crystal
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Abstract
The utility model provides a filtering apparatus for a cross wavelength division multiplexing device. The filtering device is composed of a light splitter, a light path difference introducing unit, a half wave plate and a light combiner. The light splitter and the light combiner are respectively composed of a first right trapezoid birefringence crystal wedged piece, a glass flat piece and a second right trapezoid birefringence crystal wedged piece which are connected in sequence to form a polarization splitting prism. The light path difference introducing unit is composed of two optical flat pieces, and the refractive index thermal coefficient of at least one optical flat piece is a negative value. The filtering device is good in temperature stability and high in reliability, and the dimension of optical components and the cost are greatly reduced.
Description
Technical field
The utility model relates to the optical passive component in a kind of optics and Fiber Optical Communication System, relates in particular to a kind of interleaver filter unit structure.
Background technology
DWDM is a kind of optical passive component that in same optical fiber, the light of many different wave lengths is combined simultaneously and transmitted, and along with people improve constantly the demand of information capacity and transmission speed, DWDM being is also constantly is being researched and developed by people and perfect.Wherein, Interleaver device is exactly a kind of DWDM wave-dividing device of excellent performance.Interleaver device is a kind of crossover wavelength multiplexer for optical-fibre communications field, it comprises an input end and two output terminals, adjacency channel frequency interval is that the signal of Δ f is inputted from input end, by being separated into strange, even two groups of signals that difference on the frequency is 2 Δ f after Interleaver, respectively from two output terminal outputs.At present, Interleaver device has three types, Mach-zehnder interferometer, Fabry-Perot interferometer and crystal-type.But they all exist defect, as Mach-zehnder interferometer needs accurately to control two optical fiber cable length, technological requirement is very high.Fabry-Perot interferometer adopts resonator cavity to improve live width, and effect is limited, and owing to using etalon structure dispersion differences, contrast is also restricted.Crystal-type is that cost is higher, and volume is larger, and price is comparatively expensive.
At present, patent about the filter of Interleaver device has a lot, Chinese utility model patent CN203069824U as disclosed in 2013-07-17, for another example US Patent No. 20020154845, US6694066, US7173763, their common ground is all to have adopted PBS film realize the light splitting of light beam and close light, but not only extinction ratio is not high to produce light beam with PBS film, and splitting ratio is comparatively responsive to temperature, and the most important thing is the poor reliability of rete, thereby make Interleaver device global reliability low.In the filter unit of Chinese patent CN203069824U, optical path difference is introduced device and has been adopted a YVO
4crystal and bbo crystal combination, not only cost is high, and interference waveform centre wavelength is comparatively responsive to temperature, need to add temperature compensation sheet to carry out compensating light path difference, and structure is comparatively complicated.
Utility model content
The technical problems to be solved in the utility model, is to provide a kind of filter of interleaver, has better temperature stability, and higher reliability can also greatly reduce the size of optical element and reduce costs.
The utility model is achieved in that a kind of filter of interleaver, introduces device, 1/2nd wave plates and splicer part form by light-splitting device, optical path difference; Described light-splitting device is connected successively and is combined to form a polarization splitting prism by one first right-angled trapezium birefringece crystal angle of wedge sheet, a glass planar sheets and one second right-angled trapezium birefringece crystal angle of wedge sheet with described splicer part; The optical axis of described first, second right-angled trapezium birefringece crystal angle of wedge sheet is parallel to each other, and is the birefringece crystal of material of the same race, and angle of wedge face is parallel to each other and all towards glass planar sheets; Two logical light faces of described glass planar sheets are parallel to each other, and refractive index is between the O light of the first or second right-angled trapezium birefringece crystal and the refractive index of E light; The right angle face of first, second right-angled trapezium birefringece crystal angle of wedge sheet in described light-splitting device is respectively the plane of incidence and exit facet; The right angle face of the second, first right-angled trapezium birefringece crystal angle of wedge sheet of described splicer part is respectively the plane of incidence and exit facet; / 2nd described wave plates are zero-th order waveplates or rudimentary wave plates of being made by birefringece crystal material, its optical axis be parallel to logical light face and with the optical axis of first and second right-angled trapezium birefringece crystal angle of wedge sheet in angle of 45 degrees; Described optical path difference is introduced device and is made up of two optics plain films, and the refraction temperature coefficient that wherein has an optics plain film at least is negative value.The refractive index of these two optics plain films is respectively n1, n2, thermal refractive index coefficient is respectively β 1, β 2, thermal expansivity is respectively α 1, α 2, and thickness d 1, the d2 on two optics plain film optical directions meets following relational expression: β 1 × d1+ β 2 × d2+ α 1 × d1 × n1+ α 2 × d2 × n2=0.
Further, the optical path difference of described optical path difference introducing device is: △ d=(n1 × d1+n2 × d2)-(d1+d2).
Further, the material of described two optics plain films is glass or is crystal, or one is that glass and another piece are crystal.
The utlity model has following advantage: the filter of interleaver of the present utility model adopts light-splitting device and splicer part realize light beam beam splitting and close bundle, and light-splitting device and splicer part combine a glass planar sheets and form a polarization splitting prism and realize by being connected in the middle of two right-angled trapezium birefringece crystal angle of wedge sheets, realize light beam beam splitting and close bundle with PBS film than tradition, there is higher extinction ratio, wider wavelength bandwidth, temperature is had to better stability, higher reliability; The utility model also produces optical path difference with two optics plain films, optical path difference temperature variation being caused due to two optics plain films has self-compensating function, therefore make interleaver filter unit have good stability to temperature, and owing to there being larger refringence in two light paths, therefore can greatly reduce the size of optical element, cost is also comparatively cheap.In conjunction with small size and low-cost advantage and good temperature stability and the feature of high reliability, make the Interleaver that is less than 50GHZ, 25GHZ be able to better realization.
Brief description of the drawings
In conjunction with embodiment, the utility model is further described with reference to the accompanying drawings.
Fig. 1 is the structural representation of the filter of the utility model interleaver.
Embodiment
As shown in Figure 1, the utility model interleaver filter, by light-splitting device 1, optical path difference is introduced device 1/2nd, two wave plate 3, and splicer part 4 forms.
Wherein said light-splitting device 1 is connected successively and is combined to form a polarization splitting prism by one first right-angled trapezium birefringece crystal angle of wedge sheet 41, a glass planar sheets 42 and one second right-angled trapezium birefringece crystal angle of wedge sheet 43 with described splicer part 4;
The optical axis of described the first right-angled trapezium birefringece crystal angle of wedge sheet 41, the second right-angled trapezium birefringece crystal angle of wedge sheet 43 is parallel to each other, and is the birefringece crystal of material of the same race, and angle of wedge face is parallel to each other and all towards glass planar sheets 42; Two logical light faces of described glass planar sheets 42 are parallel to each other, and refractive index is between the first right-angled trapezium birefringece crystal angle of wedge sheet 41 or the second O light of right-angled trapezium birefringece crystal 43 and the refractive index of E light.
The first right-angled trapezium birefringece crystal angle of wedge sheet 41 in described light-splitting device 1, the right angle face of the second right-angled trapezium birefringece crystal angle of wedge sheet 43 are respectively the plane of incidence and exit facet; The second right-angled trapezium birefringece crystal angle of wedge sheet 43 of described splicer part 4, the right angle face of the first right-angled trapezium birefringece crystal angle of wedge sheet 41 are respectively the plane of incidence and exit facet.
/ 2nd described wave plates are zero-th order waveplates or rudimentary wave plates of being made by birefringece crystal material, its optical axis be parallel to logical light face and with the optical axis of first and second right-angled trapezium birefringece crystal angle of wedge sheet in angle of 45 degrees;
In this embodiment, the material of the first right-angled trapezium birefringece crystal angle of wedge sheet 41 and the second right-angled trapezium birefringece crystal angle of wedge sheet 43 is icelandspar (CaCO3) birefringece crystal, and glass planar sheets 42 is optics plain films of being made by the H-BaK8 glass material of Chengdu light.When the first right-angled trapezium birefringece crystal angle of wedge sheet 41, glass planar sheets 42 and the second right-angled trapezium birefringece crystal angle of wedge sheet 43 connect, can be integral by chemical bonding.
Described optical path difference is introduced device 2 and is made up of two optics plain films, and it can be the combination of two blocks of glass or two crystal or a glass and a crystal, and the refraction temperature coefficient that wherein has an optics plain film at least is negative value.If the refractive index of these two optics plain films is respectively n1, n2, thermal refractive index coefficient is respectively β 1, β 2, thermal expansivity is respectively α 1, α 2, and thickness d 1, the d2 on two optics plain film optical directions meets following relational expression: β 1 × d1+ β 2 × d2+ α 1 × d1 × n1+ α 2 × d2 × n2=0.And the computing formula of its optical path difference is: △ d=(n1 × d1+n2 × d2)-(d1+d2).
In the present embodiment, optics plain film 21 is SCHOTT N-BK7, and another optics plain film 22 materials are α-bbo crystal, and in light path, the polarization state direction of line polarisation is parallel to its optical axis, and light is propagated along crystal a axle.For the Interleaver of 100GHz, the logical light length of glass planar sheets 21 is 1.2915 millimeters, and the logical light length of α-bbo crystal 22 is 1.609 millimeters.
The concrete filter unit principle of work of the utility model as shown in Figure 1, a series of fixed wave length interval light λ
1, λ
2λ
2n, λ
2n+1incide light-splitting device 1, be divided into the orthogonal two linearly polarized light O light of polarization state and E light, and the orthogonal linearly polarized light of two-way polarization state is from the parallel outgoing of light-splitting device 1, wherein propagate in air on a road, another route polarized light enters optical path difference and introduces device 2, compared with another road, produce optical path difference, and optical path difference changes with wavelength.This two-way light enters 1/2nd wave plates 3, there are 90 degree rotations in its linear polarization, this two-way light reenters to be mapped to after bundling device 4 closes bundle polarization interference occurs afterwards, and incident wavelength is divided into two groups of odd evens, present two groups of orthogonal linearly polarized lights of polarization state, thereby reach the effect of comb filtering.
The filter of interleaver of the present utility model adopts light-splitting device and splicer part realize light beam beam splitting and close bundle, and light-splitting device and splicer part combine a glass planar sheets and form a polarization splitting prism and realize by being connected in the middle of two right-angled trapezium birefringece crystal angle of wedge sheets, realize light beam beam splitting and close bundle with PBS film than tradition, there is higher extinction ratio, wider wavelength bandwidth, temperature is had to better stability, higher reliability; The utility model also produces optical path difference with two optics plain films, optical path difference temperature variation being caused due to two optics plain films has self-compensating function, therefore make interleaver filter unit have good stability to temperature, and owing to there being larger refringence in two light paths, therefore can greatly reduce the size of optical element, cost is also comparatively cheap.In conjunction with the feature of small size and low-cost advantage and high reliability, make the Interleaver that is less than 50GHZ, 25GHZ be able to better realization.
Although more than described embodiment of the present utility model; but being familiar with those skilled in the art is to be understood that; our described specific embodiment is illustrative; instead of for the restriction to scope of the present utility model; those of ordinary skill in the art are in equivalent modification and the variation done according to spirit of the present utility model, all should be encompassed in the scope that claim of the present utility model protects.
Claims (3)
1. a filter for interleaver, is characterized in that: introduce device, 1/2nd wave plates and splicer part by the light-splitting device setting gradually, optical path difference and form;
Described light-splitting device is connected successively and is combined to form a polarization splitting prism by one first right-angled trapezium birefringece crystal angle of wedge sheet, a glass planar sheets and one second right-angled trapezium birefringece crystal angle of wedge sheet with described splicer part; The optical axis of described first, second right-angled trapezium birefringece crystal angle of wedge sheet is parallel to each other, and is the birefringece crystal of material of the same race, and angle of wedge face is parallel to each other and all towards glass planar sheets; Two logical light faces of described glass planar sheets are parallel to each other, and refractive index is between the O light of the first or second right-angled trapezium birefringece crystal and the refractive index of E light;
The right angle face of first, second right-angled trapezium birefringece crystal angle of wedge sheet in described light-splitting device is respectively the plane of incidence and exit facet; The right angle face of the second, first right-angled trapezium birefringece crystal angle of wedge sheet of described splicer part is respectively the plane of incidence and exit facet;
/ 2nd described wave plates are zero-th order waveplates or rudimentary wave plates of being made by birefringece crystal material, its optical axis be parallel to logical light face and with the optical axis of first and second right-angled trapezium birefringece crystal angle of wedge sheet in angle of 45 degrees;
Described optical path difference is introduced device and is made up of two optics plain films, the refraction temperature coefficient that wherein has an optics plain film at least is negative value, the refractive index of these two optics plain films is respectively n1, n2, thermal refractive index coefficient is respectively β 1, β 2, thermal expansivity is respectively α 1, α 2, and thickness d 1, the d2 on two optics plain film optical directions meets following relational expression: β 1 × d1+ β 2 × d2+ α 1 × d1 × n1+ α 2 × d2 × n2=0.
2. the filter of a kind of interleaver according to claim 1, is characterized in that: the optical path difference that described optical path difference is introduced device is: △ d=(n1 × d1+n2 × d2)-(d1+d2).
3. the filter of a kind of interleaver according to claim 1, is characterized in that: the material of described two optics plain films is glass or is crystal, or one is that glass and another piece are crystal.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201420183464.6U CN203894435U (en) | 2014-04-15 | 2014-04-15 | Filtering apparatus for cross wavelength division multiplexing device |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201420183464.6U CN203894435U (en) | 2014-04-15 | 2014-04-15 | Filtering apparatus for cross wavelength division multiplexing device |
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| CN203894435U true CN203894435U (en) | 2014-10-22 |
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| CN201420183464.6U Expired - Lifetime CN203894435U (en) | 2014-04-15 | 2014-04-15 | Filtering apparatus for cross wavelength division multiplexing device |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103955027A (en) * | 2014-04-15 | 2014-07-30 | 福建华科光电有限公司 | Filtering device of cross-wavelength wavelength division multiplexer |
-
2014
- 2014-04-15 CN CN201420183464.6U patent/CN203894435U/en not_active Expired - Lifetime
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103955027A (en) * | 2014-04-15 | 2014-07-30 | 福建华科光电有限公司 | Filtering device of cross-wavelength wavelength division multiplexer |
| CN103955027B (en) * | 2014-04-15 | 2016-08-03 | 福建华科光电有限公司 | A kind of filter of interleaver |
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| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| AV01 | Patent right actively abandoned |
Granted publication date: 20141022 Effective date of abandoning: 20160803 |
|
| C25 | Abandonment of patent right or utility model to avoid double patenting |