CN2415547Y - Reflection comb wavelength division device - Google Patents

Abstract

The utility model provides a comb wave division device in optical fiber communication. The reflection comb wavelength division device mainly comprises an input and output device composed of a three-core collimator and a trapezoidal prism, a polarization light divider, a birefringence crystal filter and a reflection type parallel light polarization light divider. Light is returned and then is output after filtered by the birefringence crystal filter, delayed by lambda/2 phase, compensated by PMD and the polarization light divider again to make the input and the output positioned at the same side of the filter. The reflection type parallel light polarization light divider can make light return through two modes: a rectangular prism or a flat reflector. The utility model uses the first-stage filter to realize two-stage filtering effect, and enhances channel isolation degree and reduces volume.

Description

The long device of reflection-type Comb for dividing waves

The utility model relates to the long device of a kind of reflection-type Comb for dividing waves, belongs to the optical communication technique field.

Along with the development of optical communication technique, the information transmitted amount grows with each passing day in the optical fiber, and the particularly development on all optical network road is to the higher requirement of technology proposition of optical passive components such as dense wave division multipurpose (DWDM), optical switch.At present dense wave division multipurpose (DWDM) mainly adopts grating, fiber waveguide, interference filter element, methods such as birefringence filtering, but, just need better method to come separate signal and composite signal along with the further raising of dense wave division multipurpose channel separation dense degree.Adopting the wavelength division device of birefringece crystal filter plate is exactly wherein a kind of method preferably.In the method for general design, that adopts single-stage filtering can reduce device volume, but makes channel isolation not high.Adopt twin-stage filtering owing to needs two birefringece crystal filter plate groups, makes complex structure, and volume is big, and required device is many, has improved production cost.

The purpose of this utility model is to adopt the method for light reflection, utilizes one group of birefringence filter plate, realizes the effect of two-stage filtering, improves the isolation of two delivery channels, has reduced device, reduced volume.

The technical solution of the utility model is: light path is mainly passed through loader 1, polarizing beam splitter 2, λ/2 phase delay chips 4, filter 5, polarizing beam splitter 6 to output, it is characterized in that entering after light is through birefringece crystal filter body device 5 and can make the reverse reflective directional light polarizing beam splitter 6 of output light, light is returned pass through birefringece crystal filter 5, λ/2 phase delay chips 4, polarizing beam splitter 2 once more, the input of light and the homonymy of output at filter to output.

A kind of embodiment of the above-mentioned long device of reflection-type Comb for dividing waves is that reflective parallel polarization optical splitter 6 is made up of polarizing beam splitter 6-1 and right-angle prism 6-2, and what the inclined-plane of right-angle prism was parallel to polarizing beam splitter faces face mutually.

The another kind of embodiment of the above-mentioned long device of reflection-type Comb for dividing waves is that reflective directional light polarizing beam splitter 6 is symmetrically placed in the front side of polarizing beam splitter 6-1 by λ/2 phase delay chip 6-3,6-4, the rear side of polarizing beam splitter 6-1 is λ/4 phase delay chip 6-5, is plane mirror 6-2 at last.

The above-mentioned long device of reflection-type Comb for dividing waves, it is characterized in that light wave input and output shared one by three core collimaters and Dove prism or three input and output devices that single core collimator array is formed.

The above-mentioned long device of reflection-type Comb for dividing waves is provided with PMD polarization mode dispersion compensator 3 between polarizing beam splitter 2 and phase delay chip.

The utility model has the advantages that provides a kind of new method to realize separating of dense wave division multipurpose (DWDM) signal and merging.First advantage of this structure is to realize recycling to birefringece crystal filter plate group by reflection, reaches the effect of double-smoothing, improved device channel isolation, reduced device, dwindled volume.Second advantage is that this structure does not have the polarization requirement to input light, promptly with polarization irrelevant.The 3rd advantage is the method that this structure provides a kind of compensating polarization mode dispersion (PMD), and abatement device polarization mode dispersion (PMD) is to the influence of system.Making wavelength division device spare with this method can be coupled to odd column in a branch of dense wave division multipurpose flashlight and even column signal respectively in the different optical fiber, realizes channel spacing is become the purpose of original twice, has been equivalent to realize the demultiplexing of signal.This device also can be coupled to two equidistantly staggered column signals in the same optical fiber, realizes the multiplexing of signal.This method can also be by the change to the birefringence filter plate, devices such as the optical switch of the reflection-type high-isolation of realization 1 * 2, optical attenuator, optical modulator.

Below accompanying drawing is described, and further specify structural representation, Fig. 2 that its operation principle: Fig. 1 is first kind of embodiment of the utility model be Fig. 1 embodiment overlook index path, Fig. 3 be PMD light path end view, Fig. 4 be structural representation, Fig. 5 of second kind of embodiment of the utility model be Fig. 4 embodiment overlook index path, Fig. 6 is that PMD light path end view, Fig. 7 adopt collimator array example structure schematic diagram among Fig. 4, Fig. 8 is the structural representation of collimator array.1 is input among the figure, 1-1 is that three core collimaters, 1-2 are that Dove prism, 1-3 are three collimator arrays, the 2nd, polarizing beam splitter, the 3rd, and PMD compensates plain film, the 4th, λ/2 phase delay wave plates, the 5th, birefringece crystal filter plate group, the 6th, reflective directional light polarizing beam splitter, 6-1 are that polarizing beam splitter, 6-2 are right-angle prisms, 6-3,6-4 are that λ/2 phase delay chips, 6-5 are that λ/4 phase delay chips, 6-7 are plane mirrors.

Contain the wave train-1 and the wave train-2 in the input light among Fig. 2, we define the wave train-1, the wave train-2 like this, wherein the wave train-1 is meant that those change into [2K Π] a series of wavelength mutually by position, birefringece crystal filter plate group 5 back, after the wave train-2 was meant that those pass through birefringece crystal filter plate group 5, phase change was [(2K+1) Π] a series of wavelength.Light L101 is by polarizing beam splitter 2, wherein L106B is identical with L106A by glass planar sheets 3, λ/its polarization direction, 2 phase delay wave plates, 4 back, L106B and optical path difference that L106A walks are compensated simultaneously, promptly because the PMD that polarizing beam splitter 2 is produced is compensated, its compensation principle can describe in detail in the back.Because L106A has identical character with L106B in the light path of back, therefore only analyze wherein a kind of getting final product.L106 by birefringence filter plate group 5 after, because the wave train-1, the phase change of the wave train-2 is different, so its polarization direction is also different, in L108, polarization orthogonal is the wave train-1 in paper, what be parallel to paper is the wave train-2, L108 passes through polarizing beam splitter 6-1 the wave train-1, the wave train-2 is split up into L111 and L110, L110, L111 by prism 6-2 after exchange position only put, because the difference of polarization state, L110 downward bias is returned as L109 under the effect of polarizing beam splitter 6-1, L111 vertically is returned as L107 by polarizing beam splitter 6-1, L107, L109 is once more by birefringece crystal filter plate group 5, reach the effect of double-smoothing, make the light L109 of the wave train-2 become the polarization direction L105 vertical simultaneously with paper, so L104, L105, L106 has identical polarization direction, and is in same plane, L104, L105 is by 4,3, it is parallel with L101 and be in the light of same horizontal plane to become two bundles after 2.Be coupled to three single core collimator array 1-2 then or be coupled among one the three core collimater 1-1, in the making of reality,, can be placed on Dove prism 1-2 between 4,5 for saving the space by the effect of a Dove prism 1-2.L201 in Fig. 5, L206, L101 among L208 and Fig. 3, L106, L108 analyzes identical, L210 is the wave train-2, L211 is the wave train-1, L210, L211 is by λ/4 phase delay wave plate 6-5, change λ/2 to the position behind the plane mirror 6-2, its polarization direction is with original vertical, allow them pass through 6-3 respectively, two λ of 6-4/2 phase delay wave plates, their polarization is become with identical originally, L207 is the wave train-2, L209 is the wave train-1, L207 by birefringence filter plate group 5 after, it is vertical with paper that the polarization direction becomes, L209 is constant by birefringence filter plate group 5 rear polarizer directions, so L104, L105, L106 has identical polarization direction, and is in same plane, and the light path of back is identical with Fig. 3.Fig. 3 is two embodiment by the light path end views of compensator 3, it reacted light through polarizing beam splitter, PMD compensator after the optical path states of L106 and L206.It has reacted the effect of compensating polarization mode dispersion.Fig. 7 is collimator lens array 1-3, and the V-type groove of fixed fiber is arranged on the 1-3-1, and 1-3-2 is a collimating lens.

Fig. 9,10 is respectively and adopts three leaf length to be approximately the birefringece crystal filter plate group of the YV04 crystal arrangement one-tenth of 7mm, and the distance of two transmission peaks is about 100GHZ in the drawings.Fig. 9 is the spectrogram of single-stage filtering, and Figure 10 is the spectrogram of two-stage filtering, and their spectral line comparative result is as follows:

	-0.5dB	-1.0dB	-3.0dB	-25.0dB	-30.0dB
						Single-stage filtering	0.45	?0.55	?0.76	?1.35	?1.40
Two-stage filtering	0.37	?0.45	?0.62	?1.15	?1.21

Embodiment of the present utility model has been provided the embodiment of two kinds of wavelength division devices by technique scheme and description of drawings, a kind of is that the employing right-angle prism is the scheme of reflective body, and a kind of is to be the scheme of reflective body with the plane mirror.Fig. 1 is the reflective directional light polarizing beam splitter that adopts prism, exit direction is opposite with incident direction, but light is in same horizontal plane, the separating distance of emergent ray is determined by birefringece crystal, relevant with the birefringence of the optical axis direction of crystal, crystal length, crystal, crystal can be selected YV04, TiO ₂, a-BBO, CaCO ₃Deng.When for example adopting length to be the YV04 crystal of 10mm, the separating distance of two emergent lights is about 1mm.Fig. 4 adopts plane reflection to add the reflective directional light polarizing beam splitter of λ/4 phase delay wave plates, because the effect of the wave plate of 45 ° of optical axis directions, λ/4 phase delays, the two polarised light polarization states that make separation are with original vertical, and former polarization state can add 45 ° of optical axis directions, λ/2 phase delay wave plate 6-3,6-4 gets final product if will become again.

The structure of the compensating polarization mode dispersion (PMD) that the utility model employing compensating polarizing optical splitter causes.The light path difference of in polarizing beam splitter, being walked, thereby the compensating polarization mode dispersion that causes (PMD) owing to O light, E light.Here compensate, reach the purpose of eliminating polarization mode dispersion (PMD) by light path to the short wherein a branch of light of light path.For example to 7mm long, optical axis direction is that the polarization mode dispersion (PMD) that 45 ° YV4 polarizing beam splitter is produced is mended, the optical path difference that can calculate O light and E light earlier is about 0.89mm, if adopt K9 glass to compensate, require the thickness of glass to be about 1.78mm.

In this reflection-type wavelength division device structure, by birefringence filter plate group is changed, add electrooptic modulation, magneto-optic modulation or other modulator approach, can make reflection type optical switch etc.For example: when replacing the filter plate group just to finish the effect of optical switch with the controllable birefringece crystal of a slice phase delay.

Claims (6)

1, the long device of a kind of reflection-type Comb for dividing waves, light path is mainly passed through loader (1), λ/2 phase delay devices (4), filter (5), polarizer (6) to output, it is characterized in that entering after light is through birefringece crystal filter body device (5) and can make the reverse reflective directional light polarizing beam splitter (6) of output light, light is returned pass through filter (5), λ/2 phase delay devices (4), polarizing beam splitter (2) once more, the input of light and the homonymy of output at filter to output.

2, the long device of Comb for dividing waves according to claim 1 is characterized in that reflective directional light polarizing beam splitter (6) is made up of polarizing beam splitter (6-1) and right-angle prism (6-2), and what the inclined-plane of right-angle prism was parallel to polarizing beam splitter faces face mutually.

3, the long device of Comb for dividing waves according to claim 1 and 2, it is characterized in that reflective directional light polarizing beam splitter (6) is symmetrically placed in the front side of polarizing beam splitter (6-1) by λ/2 phase delay chips (6-3), (6-4), the rear side of polarizing beam splitter (6-1) is λ/4 phase delay chips (6-5), is plane mirror (6-2) at last.

4, the long device of Comb for dividing waves according to claim 1 and 2 is characterized in that shared one of light wave input and output add the input and output device that Dove prism or three collimator arrays are formed by three core collimaters.

5,, it is characterized in that shared one of light wave input and output add the input and output device that Dove prism or three collimator arrays are formed by three core collimaters according to claim 1 or the long device of 3 described Comb for dividing waves.

6, the long device of Comb for dividing waves according to claim 1 is characterized in that being provided with PMD polarization mode dispersion compensator 3 between polarizing beam splitter 2 and λ/2 phase delay devices 4.

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