CN101718938A - Dispersion control module and wavelength separator - Google Patents
Dispersion control module and wavelength separator Download PDFInfo
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- CN101718938A CN101718938A CN200910212661A CN200910212661A CN101718938A CN 101718938 A CN101718938 A CN 101718938A CN 200910212661 A CN200910212661 A CN 200910212661A CN 200910212661 A CN200910212661 A CN 200910212661A CN 101718938 A CN101718938 A CN 101718938A
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Abstract
The invention provides a dispersion control module and a wavelength separator comprising the dispersion control module and can enable light with various wavelengths to be in linear distribution in space. The dispersion control module is composed of a dispersion prism and a reflection grating, parallel light containing various wavelength components is incident on the surface of the reflection grating via the dispersion prism to form a first-order diffraction, and diffracted light permeates through the dispersion prism once again to enable the diffracted light in different wavelengths to be in linear distribution in space. The wavelength separator is composed of the dispersion control module, a micro collimator, a collimating lens and a wavelength separating module, wherein the micro collimator is arranged on a focal plane of the collimating lens; incident light containing various wavelength components is collimated by the collimator and is integrated into parallel light by the collimating lens to enable the diffracted light in different wavelengths to be in linear distribution in space via the dispersion control module, and then enters the wavelength separating module via the collimating lens for processing. The invention has excellent dispersion linearity, thus facilitating designing and manufacturing of other optical devices.
Description
Technical field
The present invention relates to a kind of dispersion control module and wavelength separator, belong to the photoelectron technology field.
Background technology
Entered since 21 century, along with the arrival of information age, human more and more higher to the requirement of the communication technology.Advantages such as optical communication is big with its capacity, cost is low, reliability is high, speed is fast have been brought new revolution to the information age.In numerous optical communication techniques, Fibre Optical Communication Technology relies on that its message capacity is big, signal is harassed little, good confidentiality, strong, the transmission quality advantages of higher of anti-electromagnetic interference capability, shows one's talent rapidly therein, becomes one of main pillar of modern communications.The particularly proposition of notion such as the diversity of information service and Fiber to the home (FTTH), all optical network, but the dirigibility of Fibre Optical Communication Technology, intellectuality dynamic assignment etc. are had higher requirement.Everything will make that Fibre Optical Communication Technology is further developed, and drives the development and the innovation of various active and passive devices in the optical fiber communication.
Wavelength separator is a kind of optical passive component that can be used for wavelength-division multiplex system, is one of core devices of Reconfigurable Optical Add/drop Multiplexer (ROADM).The effect of wavelength separator is the node place at wavelength-division multiplex system, and the wavelength optical signals of transmitting on the same optical fiber is carried out demultiplexing, independently must carry out the modulation of conducting, obstruct and decay then to each signal.Under the conducting state, can make signal continue in fiber optic network, to transmit; Under the obstruct state, can stop signal to continue in optical-fiber network, to transmit, discharge passage simultaneously,, can upload signal again, realize the flexible up-downgoing of signal with identical wavelength at this node place by multiplexing mode; In addition, the mode by decay can flatten the signal intensity of each passage.
Therefore, at the intermediate node of fiber optic network wavelength is carried out road up and down by wavelength separator, realized efficient, flexibly, can remote-operated wavelength transmission, be very easy to carrying out of all kinds of novel business, improved reaction velocity to client's new demand.Simultaneously, also more help carrying out the network planning, increase work efficiency, cut operating costs.
The structure of common wavelength separator is shown in Figure 11,12.Figure 11 is the structure of wavelength separator A, incident light through Optical Fiber Transmission to demodulation multiplexer, multi-wavelength's light is spatially separated, the power that utilization dimmer or attenuator come modulated light signal, realize to intercept or the function of conducting, afterwards via multiplexer with the light signal coupled back into optical fibers, its shortcoming is the structure more complicated, need to use a plurality of devices, reliability is not high.Figure 12 is the structure of wavelength separator B, incident light is by the optical fiber outgoing, through collimated, realize beam split by grating, utilize lens that incident light is focused on the control module again, control module uses the micromechanics control technology, realizes the modulation to light signal, utilizes lens, grating and lens with the light signal coupled back into optical fibers afterwards successively, its shortcoming is the structure more complicated, used 2 gratings and 4 lens, whole optical path is longer, and stability is not very reliable, used the technology of micromechanics in addition, cost is higher, and energy consumption is big, and mechanical part damages easily.For multi-wavelength's light is spatially separated, realize the function of wavelength separator to different wave length conducting independently, decay, obstruct, above-mentioned wavelength separator has adopted demodulation multiplexer or the diffusing element of combination grating isochrome, but complex structure, multi-wavelength's light spatially can't linear separation, be unfavorable for the design and the making of other optical device in the wavelength separator, cost is higher.
Summary of the invention
The invention provides a kind of dispersion control module, the light that can make the multi-wavelength is linear distribution spatially.
The present invention also provides the wavelength separator that comprises above-mentioned dispersion control module.
Described dispersion control module, comprise dispersing prism and reflection grating, the directional light that contains the multi-wavelength composition incides the reflection grating surface through dispersing prism and produces first-order diffraction, and diffraction light sees through dispersing prism again, makes the diffraction light linear distribution spatially of different wave length.
As improvement of the present invention, described dispersion control module also was provided with first birefringece crystal before dispersing prism, first birefringece crystal is fixed with half-wave plate near a side of dispersing prism, the directional light that contains the multi-wavelength composition is divided into o light and e light after the modulation of first birefringece crystal, wherein a branch of light changes polarization state through half-wave plate, and another bundle is without half-wave plate, make o light and e light after the parallel ejaculation of first birefringece crystal all along grating high-diffraction efficiency direction polarization, incide the reflection grating surface through dispersing prism then and produce first-order diffraction, diffraction light order again sees through the dispersing prism and first birefringece crystal, makes the diffraction light linear distribution spatially of different wave length.As preferred scheme, the plane, place, the direction of propagation of this two bundles directional light of o light and e light that penetrates from first birefringece crystal is parallel with the slit of reflection grating.
Described wavelength separator, comprise above-mentioned dispersion control module, comprise that also micro-collimator, collimating mirror, wavelength intercept module, micro-collimator is positioned on the focal plane of collimating mirror, the incident light that contains the multi-wavelength composition after collimating mirror is integrated into directional light, through dispersion control module, makes the diffraction light linear distribution spatially of different wave length through the micro-collimator collimation, enter wavelength through collimating mirror then and intercept module, handle.
It can be the various structures with wavelength barriers function that described wavelength intercepts module, as preferably, described wavelength intercepts module and comprises Liquid Crystal Module and catoptron, the reflecting surface of catoptron is positioned on the focal plane of collimating mirror, described Liquid Crystal Module is by liquid crystal cell that is arranged in parallel and a pair of identical printing opacity width, the birefringece crystal of optical axis direction unanimity constitutes, filling can make the TN type liquid crystal or the electrically controlled birefringence mode liquid crystal of 90 ° of polarization of incident light attitude deflections that enter liquid crystal cell in the liquid crystal cell, and be positioned at second, between the 3rd birefringece crystal, liquid crystal cell is divided into a plurality of zones of independent control, each regional correspondence is accepted the incident light of specific wavelength, be divided into o light and e light through second birefringece crystal, o light and e light enter the 3rd birefringece crystal through liquid crystal cell, when o light and e polarization state of light remain unchanged behind liquid crystal cell, o light and e light still are two bundles when the 3rd birefringece crystal penetrates, the reflecting surface of catoptron makes the mirror reflection that can't be reflected of o light and e light enter Liquid Crystal Module between the two light beams that penetrates from the 3rd birefringece crystal; When o light and e polarization state of light changed behind liquid crystal cell, o light and e light were combined into a branch of when the 3rd birefringece crystal penetrates, and normal incidence is to the reflecting surface of catoptron, and the reflection back is returned through Liquid Crystal Module along original optical path, is coupled into micro-collimator.
As improvement of the present invention, described wavelength separator also comprises reflecting prism, incident light collimates after collimating mirror is integrated into directional light through micro-collimator, make input path generation deviation through reflecting prism, after the dispersion control module chromatic dispersion, enter wavelength through reflecting prism, collimating mirror successively and intercept module then.
Utilize reflection grating that the composition of different wave length in the incident light is spatially separated.Incident light need satisfy grating equation at the diffraction on reflection grating surface, that is: Λ (sin α+sin θ)=k λ, and wherein Λ is a grating constant, and α is an incident angle, and θ is an angle of diffraction, and k is a diffraction progression, λ is the incident light wavelength.In the present invention, after collimating mirror is integrated into directional light, therefore the incident light of different wavelength has identical incident angle to incident light through the micro-collimator collimation.Under specific incident angle, can make the incident light of 1550nm wave band produce first-order diffraction.The angle of diffraction light is only relevant with wavelength, and satisfies following relation: d θ/d λ=k/ Λ cos θ.By formula as can be known, the variation relation between angle of diffraction and the wavelength is non-linear.Dispersing prism and reflection grating are used in combination can effectively control the nonlinear diffraction that is caused by grating.The different incident light of wavelength incides on the dispersing prism with identical angle, and its emergence angle is owing to the refraction action of dispersing prism also has nothing in common with each other, and the variation relation between refraction angle and the wavelength also is non-linear.For by the nonlinear effect that reflection grating produced, can utilize the nonlinear effect of dispersing prism to compensate.Simulate and the test of actual finished product by Zemax software, all prove the effectively nonlinear effect of compensatory reflex grating of dispersing prism.
Liquid Crystal Module is made of a pair of birefringece crystal and a liquid crystal cell, and wherein liquid crystal cell is between a pair of birefringece crystal.The three-dimensional dimension of birefringece crystal is identical, the optical axis direction unanimity.Liquid crystal cell is a device well known in the art, its structure is as follows: liquid crystal cell is formed by two glass gummeds, the centre accompanies liner, liner is divided into a plurality of zones with liquid crystal cell, the thickness of liner has determined that the box of liquid crystal cell is thick, is filled with liquid crystal in the liquid crystal cell, and the face that two blocks of glass contacts with liquid crystal all is coated with the ITO electrode, electrode between each zone separates, and can realize the independence control to liquid crystal.The liquid crystal that adopts in the liquid crystal cell can be 90 ° of TN (twisted-nematic phase) type liquid crystal or electrically controlled birefringence mode liquid crystal.Be example explanation liquid crystal principle of work with 90 ° of TN types below: under the situation about not powering up, liquid crystal molecule is orthogonal arranging of liquid crystal cell two walls, makes the polarization of incident light attitude that 90 ° deflection take place.Under saturation voltage, arranging of liquid crystal molecule changes, and no longer the polarization of incident light attitude exerted an influence.As shown in Figure 2, a branch of incident light enters second birefringece crystal and is divided into o light and e light, be lower than at Liquid Crystal Module under the situation of threshold voltage, 90 ° deflection all takes place through liquid crystal cell rear polarizer attitude in o light and e light, to move ahead along the direction of dotted line among Fig. 2 after all entering the 3rd birefringece crystal, last synthetic more a branch of normal incidence is to the surface of catoptron.Since be normal incidence to mirror surface, so light will return along incident direction, and return through Liquid Crystal Module along original optical path, be coupled into micro-collimator, realize the function of conducting.In this case, because the influence of birefringece crystal, the incident light ratio that enters Liquid Crystal Module from collimating mirror is slightly high from the position of the light of the 3rd birefringece crystal ejaculation, and the difference of height just is the o light of a birefringence generation and the interval between the e light.Liquid crystal cell institute making alive is higher than under the situation of saturation voltage, 90 ° of TN type liquid crystal do not exert an influence to the polarization of incident light attitude, therefore when seeing through the 3rd birefringece crystal again, the transmission direction of two-beam is mapped to the side of catoptron at last and can't realizes normal incidence shown in solid line among Fig. 2.At this moment, incident light will no longer return along original optical path, realizes the function that intercepts.Liquid crystal cell institute making alive be higher than driving voltage but when being lower than saturation voltage, the part incident light can deflect, be that 90 ° of deflections take place for part of O light and e polarization state of light, move ahead along dotted line direction among Fig. 2 after entering the 3rd birefringece crystal, synthetic more a branch of normal incidence is to the surface of catoptron, the reflection back is returned along incident direction, return through Liquid Crystal Module along original optical path, be coupled into optical fiber, and part of O light and e polarization state of light remain unchanged, and move ahead along solid line direction among Fig. 2 after entering the 3rd birefringece crystal, are mapped to the side of catoptron and can't realize normal incidence, incident light will no longer return along original optical path, realizes the function of decay at last.The reflecting surface size and the position of catoptron should accurately be designed, make the emergent light face that can be reflected that is lower than under the threshold voltage situation reflect, the be reflected reflecting surface reflection of mirror of can't the be reflected reflecting surface reflection of mirror of emergent light under the saturation voltage situation, the situation lower part emergent light between threshold value and saturation voltage.As preferably, the center of reflecting surface coincides with the emergent light center that is lower than Liquid Crystal Module under the threshold voltage, the width of reflecting surface less than the Liquid Crystal Module beam split after the spacing of two-beam projection on reflecting surface, preferred, the width of reflecting surface is less than the o light that penetrates from second birefringece crystal and the spacing of e light projection on reflecting surface.The present invention can realize light signal is carried out the control of conducting, obstruct and decay by loading the voltage of different value.Liquid crystal cell is the part of Liquid Crystal Module most critical, can have several zones of independently controlling (as 40), each zone spatially can cover the light of definite wavelength coverage (as 100GHz), when directional light for through chromatic dispersion contain the directional light of multi-wavelength composition the time, liquid crystal cell can carry out the modulation of conducting, obstruct or decay independently to the incident light of different wave length.
Among the present invention, micro-collimator makes emergent light with less angular dispersed, realizes collimation to a certain extent.By the parameter of collimating mirror is set, make the with a tight waist of micro-collimator emergent light be positioned at just on the focal plane of collimating mirror, incident light is integrated the bigger directional light of bunchy spot through behind the collimating mirror; The effect of reflecting prism is to make light path generation deviation, helps the size of reduction of device, further improves stability.First birefringece crystal can change the polarization of incident light direction, makes that incident light can be along reflection grating high-diffraction efficiency direction.Dispersing prism plays a crucial role in this wavelength separator, enlarged the beam spot size of incident light on the one hand, make that incident light can be in the reflection grating surface irradiation to bigger scope, improve the resolution of grating, on the other hand, utilize the nonlinear effect (be the light of different wave length by prism then different emergence angle is arranged) of dispersing prism, come compensatory reflex grating institute unintentional nonlinearity characteristic (be the light of different wave length at grating surface with different angle generation diffraction, and do not have linear corresponding relation between angle of diffraction and the wavelength).Incident light incides grating surface with specific angle, produces first-order diffraction, and the light of different wave length comes with different angular dispersed, realizes the function of beam split.The diffraction light of each wavelength sees through prism again, and the further nonlinear characteristic that caused of null grating makes the diffraction light linear distribution spatially of different wave length.Afterwards, the diffraction light of each wavelength sees through first birefringece crystal, reflecting prism and collimating mirror successively, enter the respective regions of Liquid Crystal Module, wherein oppositely see through the reducible polarized state of light of first birefringece crystal, reflecting prism can make light path shorten, improve stability, collimating mirror can focus on the light through optical grating diffraction on each zone of Liquid Crystal Module.Liquid crystal cell has the zone (as 40,240 microns of each regional width, 10 microns at interval, therefore the width in a zone is 250 microns) of a plurality of width and fixed interval.By regulating aforementioned grating and prism, each zone spatially can cover the light of definite wavelength coverage (as 100GHz), each regional bias voltage by the control Liquid Crystal Module, the light of independent control different wave length, realization is to the control of light signal conducting, obstruct and decay, thus realize to one have 40 passages, frequency interval is the regulation and control of the system of 100GHz.
The present invention compared with prior art, its distinguishing feature is:
(1), compare, medium wavelength obstructing instrument of the present invention is having the comparison unique design aspect the chromatic dispersion control with wavelength separator commonly used.By two ingenious combinations with optical element (reflection grating and dispersing prism) of non-linear chromatic dispersion, the linearity of chromatic dispersion shows very excellence among the present invention, and this has brought facility also for the design and the making of other optical device, helps to reduce cost.
(2), the wavelength separator among the present invention, used the photoelectric characteristic of liquid crystal, realized that electricity consumption controls light.On this basis, can realize the Long-distance Control to light path, this point has reasonable application on system level.Simultaneously, only need very little voltage just can drive liquid crystal, effectively reduce energy consumption.
(3), the setting among the present invention, structure is simple relatively, element wide material sources, cheap are widely used in scientific research and life, have broad prospects.
Description of drawings
Fig. 1 overlooks principle of the invention synoptic diagram;
Fig. 2 is a Liquid Crystal Module principle schematic of the present invention, and wherein solid line is represented the obstruct state, and dotted line is represented conducting state, and Fig. 2 is vertical mutually with the view direction of Fig. 1;
Fig. 3 is the principle schematic of incident light through first birefringece crystal change polarization state, and Fig. 3 is vertical mutually with the view direction of Fig. 1;
The chromatic dispersion linearity of Fig. 4 comparative examples;
Fig. 5 is the chromatic dispersion linearity of embodiment;
Fig. 6 is the spectral characteristic of the wavelength separator of 40 passages of embodiment gained, 100GHz channel spacing;
Fig. 7 is the pass band width of embodiment gained wavelength separator;
Fig. 8 is the bandwidth of rejection of embodiment gained wavelength separator;
Fig. 9 is the Polarization Dependent Loss (PDL) of embodiment gained wavelength separator;
Figure 10 is the return loss (RL) of embodiment gained wavelength separator;
Figure 11 is the structural representation of prior art medium wavelength obstructing instrument A;
Figure 12 is the structural representation of prior art medium wavelength obstructing instrument B.
Embodiment
Comparative examples
As Fig. 1, each optical element except that dispersing prism is placed on the substrate by shown position.The method to set up of concrete wavelength separator is as follows:
1, according to the thought of physical Design, utilization Zemax software carries out board design, select the material and the dimensions of each optical element and optimize accordingly, determine thus each parameter in the whole optical design to comprise material, dimensions and spatial relation each other.According to designing requirement, process each optical element.Simultaneously, the pottery of a specific dimensions of processing is used for the bearing optical element as substrate.In addition, according to the practical operation needs,, process a series of complementary anchor clamps by Machine Design.
2, according to optical design micro-collimator 1, collimating mirror 2, reflecting prism 3, first birefringece crystal 4 are placed on the substrate successively, base plan is parallel with surface level.Regulate the locus and the angle of each optical element, the modulation that feasible light via micro-collimator 1 outgoing passes through collimating mirror 2, reflecting prism 3 and first birefringece crystal 4 can be transformed into along the linearly polarized light of a certain specific direction polarization, this direction is vertical, spatially parallel with substrate with the slit direction of the reflection grating 6 of placing afterwards.As shown in Figure 3, first birefringece crystal 4 is fixed with half-wave plate 12 near a side of dispersing prism, the directional light that contains the multi-wavelength composition is divided into o light and e light after the modulation of first birefringece crystal, wherein a branch of light changes polarization state through half-wave plate 12, and another bundle is without half-wave plate 12, make o light and e light after the parallel ejaculation of first birefringece crystal all along grating high-diffraction efficiency direction polarization.
3, according to optical design reflection grating 6 is placed on the substrate.The position of accommodation reflex grating 6 and angle, make incident light to produce first-order diffraction on reflection grating 6 surfaces, the incident light of different wave length produces diffraction with different angles, and the diffracted ray of these different angles can oppositely see through first birefringece crystal 4, reflecting prism 3, collimating mirror 2 successively, guarantees that the diffraction light height spatially of each different wave length is consistent with incident light height spatially.Wherein, the light of a certain specific wavelength (described specific wavelength is not in wavelength separator control wavelength coverage) can satisfy the Littrow condition (when promptly on the reflection grating surface diffraction taking place, incident light is consistent with the angle of diffraction light), can be coupled into micro-collimator 1, this also is an important evidence of judging that each position of optical element is whether appropriate.With the dispersion characteristics that the optical fiber of one 250 micron diameter replaces liquid crystal cell to come test component, the result as shown in Figure 4.
4, according to optical design Liquid Crystal Module and catoptron 10 are added in the light path.Liquid Crystal Module is made of with a pair of identical printing opacity width, second, third consistent birefringece crystal 7,9 of optical axis direction the liquid crystal cell 8 that is arranged in parallel, liquid crystal cell 8 each zone be 250 microns at interval, be filled with 90 ° of TN (twisted-nematic phase) type liquid crystal in it.The position of regulator solution crystal module, make the diffraction light in the wavelength separator control wavelength coverage can see through liquid crystal region, and the feasible centre frequency that sees through the light of liquid crystal region satisfies the standard of ITU, adjacency channel be spaced apart 100GHz, insert loss, Polarization Dependent Loss and return loss and also all can meet the demands.In adjustment process, also to regulate the position of other optical device, particularly reflection grating 6.After Liquid Crystal Module adds, can control light distribution spatially by the size of regulating institute's on-load voltage.The position of the light that penetrates from the 3rd birefringece crystal 9 when the position of catoptron 10 is adjusted to the center of its reflecting surface 11 with on-load voltage not is contour, flush.Distance between catoptron 10 and the collimating mirror 2 should and micro-collimator 1 and collimating mirror 2 between distance consistent, diffraction light focuses on catoptron 10 surfaces behind collimating mirror 2.After treating that all indexs all meet, all optical elements are fixed on the substrate successively, and finish last encapsulation.
Embodiment
As Fig. 1, each optical element is placed on the substrate by shown position.The method to set up of concrete wavelength separator is as follows:
1, according to the thought of physical Design, utilization Zemax software carries out board design, select the material and the dimensions of each optical element and optimize accordingly, determine thus each parameter in the whole optical design to comprise material, dimensions and spatial relation each other.According to designing requirement, process each optical element.Simultaneously, the pottery of a specific dimensions of processing is used for the bearing optical element as substrate.In addition, according to the practical operation needs,, process a series of complementary anchor clamps by Machine Design.
2, according to optical design micro-collimator 1, collimating mirror 2, reflecting prism 3, first birefringece crystal 4 are placed on the substrate successively, base plan is parallel with surface level.Regulate the locus and the angle of each optical element, the modulation that feasible light via micro-collimator 1 outgoing passes through collimating mirror 2, reflecting prism 3 and first birefringece crystal 4 can be transformed into along the linearly polarized light of a certain specific direction polarization, this specific direction is vertical, spatially parallel with substrate with the slit direction of the reflection grating 6 of placing afterwards.As shown in Figure 3, first birefringece crystal 4 is fixed with half-wave plate 12 near a side of dispersing prism, the directional light that contains the multi-wavelength composition is divided into o light and e light after the modulation of first birefringece crystal, wherein a branch of light changes polarization state through half-wave plate 12, and another bundle is without half-wave plate 12, make o light and e light after the parallel ejaculation of first birefringece crystal all along grating high-diffraction efficiency direction polarization.
3, according to optical design reflection grating 6 and dispersing prism 5 are placed on the substrate.The position of accommodation reflex grating 6 and dispersing prism 5 and angle, make incident light to produce first-order diffraction on reflection grating 6 surfaces, the incident light of different wave length produces diffraction with different angles, and the diffracted ray of these different angles can oppositely see through first birefringece crystal 4, reflecting prism 3, collimating mirror 2 along the incident light direction successively, guarantees that the diffraction light height spatially of each different wave length is consistent with incident light height spatially.Wherein, the light of a certain specific wavelength (described specific wavelength is not in wavelength separator control wavelength coverage) can satisfy the Littrow condition (when promptly on the reflection grating surface diffraction taking place, incident light is consistent with the angle of diffraction light), can be coupled into micro-collimator 1, this also is an important evidence of judging that each position of optical element is whether appropriate.Utilizing the nonlinear effect of dispersing prism 5 (is that the light of different wave length has different emergence angle after by prism, because described emergence angle difference is less, therefore not shown among Fig. 2, the light that enters and penetrate dispersing prism 5 is corresponding one by one), come 6 unintentional nonlinearity characteristics of compensatory reflex grating, make the diffraction light linear distribution spatially of different wave length.With the dispersion characteristics that the optical fiber of one 250 micron diameter replaces liquid crystal cell to come test component, to judge whether to meet the standard of 100GHz frequency interval and ITU, the result as shown in Figure 5.If do not meet, then need regulate all optical elements until adhering to specification.Dispersing prism 5 is 75.3 ° near the transparent surface and the angle between the reflection grating 6 of reflection grating 6 one sides.
4, according to optical design Liquid Crystal Module and catoptron are added in the light path.Liquid Crystal Module is made of with a pair of identical printing opacity width, second, third consistent birefringece crystal 7,9 of optical axis direction the liquid crystal cell 8 that is arranged in parallel, liquid crystal cell 8 each zone be 250 microns at interval, be filled with 90 ° of TN (twisted-nematic phase) type liquid crystal in it.The position of regulator solution crystal module, make the diffraction light in the wavelength separator control wavelength coverage can see through liquid crystal region, and the feasible centre frequency that sees through the light of liquid crystal region satisfies the standard of ITU, adjacency channel be spaced apart 100GHz, insert loss, Polarization Dependent Loss and return loss and also all can meet the demands.In adjustment process, also to regulate the position of other optical device, particularly reflection grating 6 and dispersing prism 5.After Liquid Crystal Module adds, can control light distribution spatially by the size of regulating institute's on-load voltage.The position of the light that penetrates from the 3rd birefringece crystal 9 when the position of catoptron 10 is adjusted to the center of its reflecting surface 11 with on-load voltage not is contour, flush.Distance between catoptron 10 and the collimating mirror 2 should and micro-collimator 1 and collimating mirror 2 between distance consistent, diffraction light focuses on catoptron 10 surfaces behind collimating mirror 2.After treating that all indexs all meet, all optical elements are fixed on the substrate successively, and finish last encapsulation.
Comparative examples and embodiment gained obstructing instrument are carried out performance test, and the result is as follows:
1. Fig. 4 is the dispersion situation of comparative examples, and ordinate is represented the different frequency of incident light, and horizontal ordinate represents that the incident light of different frequency behind the reflection grating diffraction, focuses on the locus of mirror surface.From the result of match, in this case, same frequency (or wavelength) location interval of incident light on mirror reflection surface 11 at interval is different, promptly is not linear corresponding relation.This nonlinear corresponding relation is mainly caused by the non-linear of reflection grating.In the actual fabrication process, this point can be brought influence to the processing of relevant optical, causes the rising of cost.Fig. 5 is the dispersion situation of the wavelength separator among the present invention, and longitudinal and transverse coordinate is identical with Fig. 3.From the result of match, in this case, same frequency (or wavelength) location interval of incident light on the focal plane at interval is identical, is linear corresponding relation.Simultaneously, same frequency incident light at interval, under the situation of adding dispersing prism, the chromatic dispersion of whole optical path is bigger, and what promptly incident light was spatially dispersed more opens, and more helps light is regulated and control.Therefore, by contrast, fully showed the vital role that is combined in the wavelength separator to be brought into play of dispersing prism and reflection grating.
2. as shown in Figure 6, the spectral characteristic of embodiment gained wavelength separator is: odd chanel voltage is zero, inserts loss (IL) and is about 5dB, and per four passages of even-numbered channels power up 2.20V, 2.55V, 2.85V, 3.65V respectively, and wherein 3.65V is a saturation voltage.Under these voltages, loss is respectively 10dB, 20dB, 30dB and near 40dB.The contrast of medium wavelength obstructing instrument of the present invention more than 40dB, meets the needs in current market substantially.
3. as shown in Figure 7, embodiment gained wavelength separator is about 73.8GHz at the channel bandwidth of 3dB.
4. as shown in Figure 8, embodiment gained wavelength separator is about 61.0GHz in the bandwidth of rejection of 30dB.
By Fig. 7,8 as seen, the bandwidth of embodiment gained wavelength separator reaches the requirement in market, and the skew of wavelength is had tolerance preferably.
5. the Polarization Dependent Loss (PDL) of embodiment gained wavelength separator as shown in Figure 9: insert loss (IL) and be respectively 5dB, 10dB and 15dB situation following time, the Polarization Dependent Loss of each passage (PDL) is respectively less than 0.4dB, 0.7dB and 1.1dB.The Polarization Dependent Loss of medium wavelength obstructing instrument of the present invention (PDL) reaches the use standard substantially.
6. the return loss (RL) of embodiment gained wavelength separator as shown in figure 10: insert loss (IL) and be respectively 5dB, 10dB and 15dB situation following time, the return loss of each passage (RL) is greater than 60dB.The return loss of medium wavelength obstructing instrument of the present invention (RL) can satisfy the requirement in market fully.
Claims (6)
1. dispersion control module, it is characterized in that comprising dispersing prism and reflection grating, the directional light that contains the multi-wavelength composition incides the reflection grating surface through dispersing prism and produces first-order diffraction, and diffraction light sees through dispersing prism again, makes the diffraction light linear distribution spatially of different wave length.
2. dispersion control module as claimed in claim 1, it is characterized in that also being provided with first birefringece crystal before the dispersing prism, first birefringece crystal is fixed with half-wave plate near a side of dispersing prism, the directional light that contains the multi-wavelength composition is divided into o light and e light after the birefringece crystal modulation, wherein a branch of light changes polarization state through half-wave plate, and another bundle is without half-wave plate, make o light and e light after the parallel ejaculation of first birefringece crystal all along grating high-diffraction efficiency direction polarization, incide the reflection grating surface through dispersing prism then and produce first-order diffraction, diffraction light order again sees through the dispersing prism and first birefringece crystal, makes the diffraction light linear distribution spatially of different wave length.
3. dispersion control module as claimed in claim 2 is characterized in that the plane, place, the direction of propagation of this two bundles directional light of o light and e light of penetrating from first birefringece crystal is parallel with the slit of reflection grating.
4. wavelength separator, comprise as each described dispersion control module among the claim 1-3, it is characterized in that also comprising that micro-collimator, collimating mirror, wavelength intercept module, the incident light that contains the multi-wavelength composition collimates after collimating mirror is integrated into directional light through micro-collimator, through dispersion control module, make to enter the diffraction light linear distribution spatially of different wave length wavelength through collimating mirror then and intercept module, handle.
5. wavelength separator as claimed in claim 4, it is characterized in that, described wavelength intercepts module and comprises Liquid Crystal Module and catoptron, described Liquid Crystal Module is by liquid crystal cell that is arranged in parallel and a pair of identical printing opacity width, the birefringece crystal of optical axis direction unanimity constitutes, filling can make the TN type liquid crystal or the electrically controlled birefringence mode liquid crystal of 90 ° of polarization of incident light attitude deflections that enter liquid crystal cell in the liquid crystal cell, and be positioned at second, between the 3rd birefringece crystal, liquid crystal cell is divided into a plurality of zones of independent control, each regional correspondence is accepted the incident light of specific wavelength, be divided into o light and e light through second birefringece crystal, o light and e light enter the 3rd birefringece crystal through liquid crystal cell, when o light and e polarization state of light remain unchanged behind liquid crystal cell, o light and e light still are two bundles when the 3rd birefringece crystal penetrates, the reflecting surface of catoptron makes the mirror reflection that can't be reflected of o light and e light enter Liquid Crystal Module between the two light beams that penetrates from the 3rd birefringece crystal; When o light and e polarization state of light changed behind liquid crystal cell, o light and e light were combined into a branch of when the 3rd birefringece crystal penetrates, and normal incidence is to the reflecting surface of catoptron, and the reflection back is returned through Liquid Crystal Module along original optical path, is coupled into micro-collimator.
6. as claim 4 or 5 described wavelength separators, it is characterized in that also comprising reflecting prism, incident light collimates after collimating mirror is integrated into directional light through micro-collimator, make input path generation deviation through reflecting prism, after the dispersion control module chromatic dispersion, enter wavelength through reflecting prism, collimating mirror successively and intercept module then.
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| CN200910212661XA CN101718938B (en) | 2009-11-13 | 2009-11-13 | Dispersion control module and wavelength separator |
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| Application Number | Priority Date | Filing Date | Title |
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| CN200910212661XA CN101718938B (en) | 2009-11-13 | 2009-11-13 | Dispersion control module and wavelength separator |
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| CN101718938A true CN101718938A (en) | 2010-06-02 |
| CN101718938B CN101718938B (en) | 2011-06-29 |
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Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102375233A (en) * | 2011-10-18 | 2012-03-14 | 中国科学院上海技术物理研究所 | Refraction and reflection type grating prism combined dispersion assembly and designing method thereof |
| CN103364879A (en) * | 2012-03-30 | 2013-10-23 | 福州高意通讯有限公司 | A flat-top optical filter with adjustable bandwidth |
| CN104991301A (en) * | 2015-07-19 | 2015-10-21 | 美昇科技（成都）有限公司 | A reflective linear frequency domain optical grating and a design method thereof |
| CN107003480A (en) * | 2016-03-01 | 2017-08-01 | 肖峰 | Wavelength selection switch device, communication equipment and wavelength switching method |
| CN112005547A (en) * | 2018-04-26 | 2020-11-27 | 索尼半导体解决方案公司 | Optical phase control device and display device |
-
2009
- 2009-11-13 CN CN200910212661XA patent/CN101718938B/en not_active Expired - Fee Related
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102375233A (en) * | 2011-10-18 | 2012-03-14 | 中国科学院上海技术物理研究所 | Refraction and reflection type grating prism combined dispersion assembly and designing method thereof |
| CN103364879A (en) * | 2012-03-30 | 2013-10-23 | 福州高意通讯有限公司 | A flat-top optical filter with adjustable bandwidth |
| CN104991301A (en) * | 2015-07-19 | 2015-10-21 | 美昇科技（成都）有限公司 | A reflective linear frequency domain optical grating and a design method thereof |
| CN107003480A (en) * | 2016-03-01 | 2017-08-01 | 肖峰 | Wavelength selection switch device, communication equipment and wavelength switching method |
| CN107003480B (en) * | 2016-03-01 | 2019-11-05 | 肖峰 | Wavelength selection switch device, communication equipment and wavelength switching method |
| CN112005547A (en) * | 2018-04-26 | 2020-11-27 | 索尼半导体解决方案公司 | Optical phase control device and display device |
Also Published As
| Publication number | Publication date |
|---|---|
| CN101718938B (en) | 2011-06-29 |
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