CN1390309A

CN1390309A - Dual grating light filtering system

Info

Publication number: CN1390309A
Application number: CN00815628A
Authority: CN
Inventors: J·阿明; J·P·康迪斯; E·R·拉那利; B·A·斯科特
Original assignee: Corning Inc
Current assignee: Corning Inc
Priority date: 1999-09-14
Filing date: 2000-08-26
Publication date: 2003-01-08
Also published as: KR20020033803A; EP1214616A1; WO2001020381A1; CA2385004A1; JP2003509719A; AU7982600A

Abstract

A light filtering assembly comprises an input section, a filtering section, and an output section. The input section divides the input beam into a plurality of polarized monochromatic beamlets that travel along a corresponding plurality of spatially separated beam paths by means of a polarization converter and a diffraction grating. The polarized monochromatic beamlets comprise a plurality of desired beamlets corresponding to the desired wavelength components of the input beam. The filtering section passes the disered beamlets blocks the unwanted beamlets. The output section combines the desired beamlets so as to form the output beam. Because the beamlets are linearly polarized, the input and output section are able to realize a high throughput efficiency.

Description

Dual grating light filtering system

Background of invention

Invention field

The present invention relates to the light wave control device, particularly relate to filter, this device can weaken input beam to realize steep relatively die-away curve according to wavelength selectivity ground.

Description of related art

Communication network more and more depends on control, transmission and the detection of electromagnetic wave or light wave, so that the bulky information bearer path to be provided.Typical optical channel can utilize one to provide the light source of modulated beam of light, the photodetector and of a demodulation light beam that the fiber optic cable of optical channel is provided.

In order to improve the information-bearing ability of communication network, there is the light of a plurality of wavelength component to transmit along optical cable, make each wavelength component advance by the passage that separates.Because be expected to make the quantity maximization of channel, wavelength component has little wavelength interval usually.

In order further to improve the information-bearing ability, light wave can be along the transmission simultaneously in the opposite direction of an optical cable.A light wave comprises desired first wavelength component, and another light wave comprises desired second wavelength component.The wavelength of first wavelength component is clipped between second wavelength component usually.

Because light wave can decayed, place multistage optical amplifier along beam channel usually when fiber optic cable is advanced.Each grade image intensifer generally includes an active medium, and it is that electricity consumption drives the medium that pump source is realized optical pump.

Along with light wave transmits along optical cable, because the integrated noise of cross interference in the channel and the wavelength component that introducing is not wanted in channel usually causes the degeneration of light wave.If allow to enter image intensifer, the wavelength component of not wanting is exaggerated with desired wavelength component, and the wavelength component of not wanting can limit the ability that photodetector detects indivedual desired wavelength component.

In order to reduce the influence of wavelength component not, lay optical filter spare in each image intensifer front usually.Under the perfect condition, lightwave filter stops optical wavelength component not fully and does not make desired wavelength component decay.But,, existing optical filter do not make the limited in one's ability of desired wavelength component decay basically because will stoping light wave component not, also because that do not want usually quite approaching each other with wavelength desired wavelength component, this class optical filter can not provide acceptable signal-to-interference ratio.

Therefore, from as seen noted earlier, have recognized the need to one and improve optical filter with the unwanted light wave of elimination, particularly, wave filter should have improved filtering characteristic, and it allows to stop wavelength component not and desired wavelength component is passed through, so that signal to noise ratio (S/N ratio) is improved.

Summary of the invention

Can satisfy above-mentioned requirements by the present invention.At first, the present invention is a kind of smooth filter, is used to filter the input beam of a plurality of desired wavelength component and a plurality of wavelength component of not wanting.The inventive system comprises the input block that is positioned on the input beam delivering path, this input block is divided into a plurality of monochromatic polariton beams with input beam, and these polariton beams are along the beam channel transmission that separates on the corresponding a plurality of spaces.A plurality of monochromatic polariton beams comprise: (a) a plurality of corresponding to the desired beamlet of desired wavelength component and (b) a plurality of beamlets of not wanting corresponding to the wavelength component of not wanting.Device of the present invention comprises that also one is placed on filter part on the beam Propagation approach to receive the desired beamlet from filter part.Filter part makes beamlet decay not and desired beamlet is passed through.Device of the present invention comprises that also an output block is to receive the desired beamlet from filter part.On this output block space desired beamlet combined with provide the desired wavelength component that comprises input beam through the filtering output beam.

Secondly, the present invention is that a kind of filtration comprises the input beam of a plurality of desired wavelength component and a plurality of wavelength component of not wanting to obtain comprising the method for crossing the output beam that filters of desired wavelength component.Method of the present invention comprises input beam is divided into along a plurality of monochromatic polariton beam of the beam channel transmission that separates on the space.Described a plurality of monochromatic polariton beam comprises: (a) a plurality of corresponding to the desired beamlet of desired wavelength component and (b) a plurality of beamlets of not wanting corresponding to the wavelength component of not wanting.Thereby make beamlet decay not from desired beamlet, remove beamlet not then.Again desired beamlet is combined to obtain the output beam of filtering.

Three, the present invention is a kind of light control device, and control has the input beam of a plurality of wavelength component to obtain output beam.The inventive system comprises the input block that is placed on the input beam delivering path.This input block is divided into incident beam the first group of monochromatic polariton beam that transmits along the beam channel that separates on corresponding a plurality of spaces.The inventive system comprises the control device of light beam that is placed on the beam channel so that control at least one light beam of first group of monochromatic polariton beam in the space correlation mode.This beamlet controller provides second group of monochromatic polariton beam.Device of the present invention also comprises lays an output block leaves the beamlet controller with reception second group of monochromatic polariton beam.This output block is constructed the output beam from second group of monochromatic polariton beam.

In one embodiment, first group of monochromatic polariton beam comprises that (a) is corresponding to a plurality of desired beamlet of a plurality of desired wavelength component in the input beam with (b) corresponding to a plurality of beamlets of not wanting of a plurality of wavelength component of not wanting in the input beam.Second group of monochromatic polariton beam comprises a plurality of desired beamlets.The beamlet controller comprises the filter part that makes not beamlet decay and desired beamlet is passed through.This filter part includes the light-proof material in a plurality of holes and is placed to such an extent that a plurality of desired beamlets are aimed at a plurality of holes and a plurality of beamlets of not wanting and a plurality of hole are not collimated.Output block spatially make up leave filter part desired beamlet to construct the output beam that comprises desired wavelength component in the input beam.

The 4th, the present invention is a light filtering system, to filter first and second input beams more than first and second institute's wavelength component of being wanted arranged respectively and the individual wavelength component of not wanting more than first and second is arranged respectively.System of the present invention comprises the input block that is placed on the first and second input beam delivering paths.Input block is divided into respectively the first and second monochromatic polariton beams along more than first and second beam channel that separates on the space respectively with first and second input beams.First and second groups of monochromatic polariton beams comprise (a) respectively corresponding to more than first and second institute's beamlets of wanting of the desired wavelength component of first and second input beams with (b) respectively corresponding to first and second groups of beamlets of not wanting of the wavelength component of not wanting of first and second input beams.System of the present invention also comprises the filter part that is placed on the passage of first and second light beams territory.Filtering portion makes more than first and second not want the beamlet decay and more than first and second beamlet of wanting passed through.System of the present invention comprises that also the output block that is placed is to receive more than first and second beamlets of being wanted from filter part.Output block spatially make up more than first the beamlet of wanting to obtain the output bundle of more than first filtering, the output bundle of this filtering comprises the desired wavelength component in first input bundle.Output block spatially makes up more than second institute's beamlet of wanting to obtain the output bundle of the second mistake filtration, and this output bundle comprises the desired wavelength component in second input beam.

As seen from above, clearly, optical dispersion device of the present invention can filter input beam so that the output beam of filtering does not have the wavelength component of not wanting in the input beam basically.And then the optical dispersion device can be with the light beam of high percent of pass by desired wavelength component.These and other some purpose of the present invention and its advantage will seem clearer from the description below in conjunction with accompanying drawing.

Description of drawings

Fig. 1 is the synoptic diagram of an embodiment that is used to filter the light filter of an input beam.

Fig. 2 and Fig. 3 are the synoptic diagram of the light filter of Fig. 1, and they illustrate that this installs formed mutually perpendicular a plurality of beam channels.

Fig. 4 is the synoptic diagram of polarization beam apparatus of the light filter of Fig. 1, and it is fit to be used for transferring nonpolarized light to substantially parallel first and second light beams that orthogonal polarization axes is arranged.

Fig. 5 is the synoptic diagram of optical dispersion device of the light filter of Fig. 1, the scattering properties that it is fit to provide stable basically response temperature to change.

Fig. 6 is explanation is changed input homogeneous beam direction in the relevant mode of wavelength by the dispersor of Fig. 5 a synoptic diagram.

Fig. 7 is the synoptic diagram of another embodiment of optical dispersion device of the light filter of Fig. 1, and it is fit to be used to provide the improvement percent of pass.

Fig. 8 is the synoptic diagram of the embodiment of light filter of Fig. 1.

Fig. 9 is the synoptic diagram of an embodiment that has improved the light filtering system of filtering characteristic, the output beam that it is fit to be used for to receive two input beams that separate and provided open through filtering in two fens in the mode of the light filter of Fig. 1.

Figure 10 is the synoptic diagram of optical dispersion subsystem of the light filtering system of Fig. 9, and it is fit to be used for heat-staple substantially two input beams of scattering respectively and improved percent of pass.

Figure 11 is the synoptic diagram of another embodiment of light filtering system that utilizes less assembly of Fig. 9; With

Figure 12 is the light filtering system that the utilizes less assembly synoptic diagram of an embodiment again of Fig. 9.

The detailed description of preferred embodiment

With reference now to accompanying drawing,, identical identical parts of digitized representation in the accompanying drawing.Fig. 1 schematically represents a light filter 30 according to one aspect of the invention.Device 30 receives input beam 32, and input beam comprises a plurality of wavelength components usually, and each wavelength components generally includes the first and second linear polarization subconstiuents of orthogonal polarization axes.A plurality of wavelength components comprise a plurality of desired wavelength component and with a plurality of wavelength component of not wanting of desired wavelength component.As can describing in detail below, device 30 not wavelength component is weakened and make desired wavelength component with high percent of pass by comprising a plurality of output beams 34 of being wanted wavelength component not comprise a plurality of wavelength components of not wanting to provide.

As schematically shown in Figure 1, device 30 comprises an input block 36, and it is divided into a plurality of monochromatic polariton beams 38 along beam channel 40 transmission that separate on a plurality of spaces with input beam 32.Beamlet 38 spatially is separated from each other by wavelength and polarization, thereby beamlet 38 is comprised corresponding to a plurality of desired monochromatic basically beamlet 42 of the first and second polariton compositions of the wavelength component of wanting of input beam 32 with corresponding to a plurality of monochromatic basically beamlets of not wanting 44 of the first and second polariton compositions of the wavelength component of not wanting of input beam 32.Each beamlet 38 occurs with linear polarization state, and linear polarization state can make the desired wavelength component of input beam pass through device 30 effectively with high percent of pass, can describe in detail below.

As shown in Figure 1, device also comprises the filter part 46 that is placed on the beam channel 40, makes beamlet 38 enter filter part.As can describing in detail below, filter part 46 optionally makes the wavelength component decay of not wanting in the input beam by the mode of the passage 40 of blocking-up beamlet 44 not.And then by allowing the mode of desired beamlet 42 by filter part 46, filter part 46 optionally makes desired set of wavelengths pass through.

As shown in Figure 1, device 30 output blocks 48 that also comprise on the passage that is placed on the desired beamlet 42 that leaves filter part 46 make beamlet 42 enter output block 48.As following can describe in detail like that, output block 48 with high percent of pass reconfigure the beamlet of being wanted 42 formation output beams 34, output beam 34 is similar substantially to the input beam 32 that has deducted the wavelength components of not wanting.

Referring now to Fig. 2 and Fig. 3, they illustrate to have described light filter 30 in more detail, and input beam 32, output beam 34 and a plurality of dynatron light beam 38 transmit along the Z axle basically.And then Fig. 2 represents that beamlet 38 is along the Y-axis deflection vertical with the Z axle, to show the response of 30 pairs of light beam polarizations of device.Fig. 3 represents that beamlet 38 is along the X-axis deflection of vertical and Y-axis and Z axle simultaneously, to show the response of 30 pairs of light beam wavelengths of device.

But concerning those skilled in the art, be apparent that the light filter can be arranged to a kind of in the various configurations.For example, light filtering system can constitute with nonlinear way, and like this, input beam 32, output beam 34 and dynatron light beam 38 be not with same direction transmission.Device 30 can comprise that also light reflection element replaces the light transmission component shown in Fig. 2 and 3.And then system 30 also can constitute with X, Y, the not orthogonal mode of Z axle.

As shown in Figures 2 and 3, the input block 36 of light filter 30 comprises a polarization converter 49, and it converts nonpolarized light to linearly polarized light with high-level efficiency.As below in conjunction with Fig. 4 write up, polarization converter preferably includes polarising beam splitter 50, and it is divided into input beam 32

output bundle

52 and 54 of first and second polarizations that the vertical polarization axle is arranged.The input beam 32 that transfers along the Z axle enters the input face 56 of beam splitter 50, is divided into first and

second light beams

52,54, and they are preferably with the output face 58 along the mode emergent light beam splitter 50 of Z substantially parallel axes, so that

light beam

52,54 departs from Y-axis each other.First light beam 52 has first polarization axle and second light beam has second polarization axle, and second polarization axle is vertical with first polarization axle.In preferred embodiment, first light beam 52 is p polarizations, thereby first polarization axle is parallel to the output face 58 of polarising beam splitter 50.And then second light beam 54 is the s polarization at first, thereby second polarization axle is perpendicular to the output face 58 of polarising beam splitter 50.

As shown in Figure 2, the polarization converter 49 of the importation 36 of device 30 also comprises first half-wave plate 60, and it places on the passage of second light beam 54 that leaves polarising beam splitter 50.Half-wave plate 60 receiving beams 54 also make the polarization axle rotation of light beam 54, and when causing light beam 54 to leave half-wave plate 60, its polarization axle is aimed at the polarization axle of first light beam 52.Then, in preferred embodiment, first and second light beams the 52, the 54th, the p polarization, make

light beam

52,54 pass through efficient by dispersor 62 chromatic dispersions of device 30 with big.

As Fig. 2, shown in Figure 3, the input block of device 30 also comprises dispersor 62, and it makes the

light beam

52,54 that leaves polarization beam apparatus by wavelength dispersion.Dispersor 62 converts

light beam

52,54 to a plurality of monochromatic beamlets 38, and it comprises the beamlet 64,66 of more than first and second chromatic dispersion respectively.Dispersor 62 places on the passage of

light beam

52,54, thereby first light beam 52 that leaves beam splitter 50 enters the input face 68 of dispersor 62 and obtains more than first beamlet 64 that looses along the plane chromatic dispersion that is parallel to X-Y plane.Similarly, thereby second light beam 54 that leaves beam splitter 50 enters the input face 68 of dispersor 62 and obtains the beamlet 66 of more than second chromatic dispersion along the Different Plane chromatic dispersion that is parallel to the X-Z plane, and it departs from the first chromatic dispersion beamlet 64 along Y-axis, as shown in Figure 2.The beamlet 38 that leaves dispersor 62 is parallel basically so that the cross section of beamlet 38 keeps uniform shapes basically.

As described below in conjunction with Fig. 5, in preferred embodiment, dispersor 62 preferably comprises a plane diffraction grating.In this preferred embodiment, grating is preferably adjusted to and is made the polarization axle of first and second light beams be parallel to grating planar.Like this, the loss relevant with polarization of grating reduces, and makes grating can realize the high efficient of passing through.

As shown in Figures 2 and 3, the input block 36 of optical dispersion device 30 also comprises concentrating element 70, a plurality of beamlets 38 that it will leave dispersor 62 focus on the parallel plane focal plane 72 of x-y on.Assemble element 70 and place on the passage 40 of a plurality of light beams 38, make beamlet 38 enter input face 74 in the mode of dispersing along being parallel to the parallel plane plane of X-Z.Assemble element make beamlet change direction so that their direction of propagation basically with parallel consistent with the plane Y-Z plane.And then, assemble element along Y-axis part deflected sub-beams 38, so that there is the corresponding beamlet of coupling wavelength on the focal plane 72 of collector 70, to intersect each other to 39.In addition, as shown in Figures 2 and 3, assemble element 70 each beamlet 38 is assembled, make that the xsect reductions of each beamlet on the focal plane 72 of collector 70 is little.

Next, the input block of optical dispersion device 30 is converted to input beam 32 a plurality of beamlets 38 that separate on the space, beamlet 38 is collected on the focal plane 72 of focuser 70, thereby obtained the intensity distribution that is narrow elongation basically, as shown in Figure 3, it extends along X-axis.Because dispersion element 62 spatially separates beamlet 38 in the mode relevant with wavelength on the X-Z plane, therefore, intensity distributions Figure 76 is also separated on the spectrum.

As shown in Figures 2 and 3, the filter part 46 of optical dispersion device 30 is settled overlappingly with the focal plane 72 of focuser 70.Filter part 46 comprises a spatial-intensity regulator, and in this preferred embodiment, this regulator is one input face 82 to be arranged, the opaque screen 80 in output face 84 and a plurality of light transmissions district 86 or hole 86, and 86 space, hole upper edge XL is with distributing.Screen 80 is located substantially on the focal plane 72 of focuser 70, and like this, intensity distributions Figure 76 that the beamlet 38 that separates on hole 86 and the spectrum is produced aligns.And then, hole 86 disposes to such an extent that a part and the hole 86 of feasible intensity distributions Figure 76 corresponding to the beamlet 42 of wanting wavelength to some extent is overlapping, also makes a part corresponding to intensity distributions Figure 76 of the beamlet 44 that wavelength is not arranged bump against the zone of opacity of 80 input face 82.

Therefore, do not have not that the beamlet 44 of wavelength is stopped by screen 80 and wants the beamlet 42 of wavelength to transmit by the output face 84 of screen 80 to some extent, as shown in Figures 2 and 3.As shown in Figure 3, beamlet 42 leaves screen 80 edges and the parallel plane planar transmission of Y-Z.As shown in Figure 2, the beamlet 42 from first polarisation beam 52 is marked with beamlet 42a below, and part is advanced along negative Y direction.Equally, the beamlet 42 from second polarisation beam 54 is marked with beamlet 42b below, and part is advanced along positive Y direction, thereby 42b and beamlet 42a disperse mutually.Like this, each beamlet 42 has the distribution that diverges to, thereby, leaving screen 80 when advancing with them, their cross-sectional area increases.

As shown in Figures 2 and 3, the output block 48 of light filter 30 comprises a collimating element 90 that input face 92 and output face 94 arranged.Collimating element 90 is placed on the passage of the beamlet of dispersing 42 that leaves screen 80, makes the beamlet of dispersing 42 enter the input face 92 of collimating element 90, and its transmission direction is consistent with the plane that is parallel to the Y-Z axial plane basically.Collimating element 90 makes beamlet 42 change directions, makes that the transmission direction of the beamlet that comes out from the output face of collimating element 90 is consistent with the plane that is parallel to the X-Z plane basically.In these parallel planes, beamlet 42a assembles each other with beamlet 42b and assembles each other, and the convergence of beamlet 42a and 42b occurs on the section 99 that is parallel to X-Y plane.Collimating element 90 is adjusted light beam 42, makes each beamlet 42 distribute with collimation and leaves the output face 94 of collimating element 90.

As shown in Figures 2 and 3, the output block 48 of light filter 30 also includes the first light beam composition element 100 of input face 102 and output face 104.Element 100 is placed on the plane of section 99, makes element 100 be in the passage of intersection beamlet 42.Beamlet 42 enters the input face 102 of element 100 and makes up with following method in greater detail.Combination results first and second composite light beams 106,108 of beamlet 42, they are respectively from more than first and second beamlet 42a and 42b.Beam combination leaves the output face 104 of element 100, basically along the direction parallel with z axle transmission, win composite light beam 106 and second composite light beam 108 is departed from along Y-axis.Because composite light beam 106,108 is from

p light beam

52,54, in preferred embodiment, composite light beam 106,108 all is the p polarization.

As shown in Figures 2 and 3, in preferred embodiment, output block also comprises the depolarization converter 110 that polarisation beam 106,108 is converted to single unpolarized output beam 34.Depolarization converter 110 comprises second half-wave plate 112, and it is positioned on the passage of first composite light beam 106.Second half-wave plate is the same with first half-wave plate 60 basically, with the turning axle rotation 90 of first composite light beam 106.As a result, in preferred embodiment, when first beam combination leaves half-wave plate 112, be the s polarization.

As shown in Figures 2 and 3, the depolarization converter of the output block 48 of light filter 30 also comprises the second light beam composition element 114, and it is with p polarized light and the s polarized light generation nonpolarized light that combines.There is the element 114 of input face 116 and output face 118 to be placed on the passage of composite light beam 106 and 108, makes light beam 106,108 enter the input face 116 of the second light beam composition element 114.When entering element 114, light beam 106,108 with the following method that can describe in detail combining, thereby obtain leaving the output beam 34 of the output face 118 of element 114.

Referring now to Fig. 4, Fig. 4 diagram has in more detail described an embodiment of the polarization beam apparatus 50 of light filter device 30.

As shown in Figure 4, beam splitter 50 has input face 56 and output face 58, and output face 54 has an input face port one 40, and output face 58 comprises two output face port ones 42,144 at least.These faces are to be that the transparent sheet 146 of T (this thickness form rigid structure) forms with thickness.Thin slice 146 comprises the first and second flat surfaces 148,150, and they are to be placed in abreast separately in the plane basically.

Input beam 32 enters the input face port one 40 of beam splitter 50 and in 152 refractions of first refracting sphere, obtains first deflecting light beams 160.The incident angle of input beam 32 is Q1 (with the folded angle of first surface 148 normals of thin slice 146).The first refraction angle Q2 of first deflecting light beams 160 (with the folded angle of the normal of second surface 150).Equation is arranged:

n _OutSin θ ₁=n _InSin θ ₂(1) n here _OutBe the refractive index of the external agency adjacent with beam splitter 50, n _InIt is the refractive index of thin slice 146.

In one embodiment, input face port one 40 comprises the antireflecting coating 162 of first relative thin, and it is placed along first refracting sphere 152 of first surface 148.The purpose of first antireflecting coating 162 is to increase the transmission of input beam 32 by first refracting sphere 152.

First deflecting light beams 160 enters the polarization district 156 of second surface 150 by 146 transmission of book sheet.Limit the second incident angle θ 3 of normal of the second surface 150 of the sheet 146 of facing a charge mutually.Because first and second surfaces 148,150 of book sheet 146 are parallel to each other basically, the second incident angle θ 3 is basically the in the first refraction angle θ 2.

Output face port one 42 comprises polarizing coating 164, and it is placed along the polarization district 156 of second surface 150.Polarizing coating 164 transmission enter the linear polarization bundle with the 1st polarization of coating 164 with the second incident angle θ 3.And polarizing coating 164 reflections one have similar second linearly polarized light beam of second polarization.In one embodiment, polarizing coating 164 adopts the coating of transmitting the p polarized light and reflecting the s polarized light.

Therefore, first polarized component of first deflecting light beams 160 is left beam splitter 50 through the first output face port one 42, thereby obtains first light beam 52 of first polarization.Particularly the light beam 52 first output angle φ 1 (with the angle of the normal of the second surface 150 of book sheet 146) that leaves first output port 142 satisfies equation

n _InSin θ ₃=n _OutSin φ ₁(2) and then, substantially equate with θ 2 that according to equation (1) and (2) and θ 3 the first output angle φ 1 is substantially equal to the first incident angle θ 1.

As shown in Figure 4, second polarized component of the first refraction bundle 160 is from polarizing coating 164 reflections, second polarization arranged and determined the first reflection angle θ 4 with respect to the normal of the second surface 150 of book sheet 146 thereby obtain first reflecting bundle, 166, the first reflecting bundles.According to reflection theorem, the first reflection angle θ 4 equals the second incident angle θ 3.

As shown in Figure 4, first reflecting bundle 166 is transferred to reflectance coating 170 by book sheet 146, and this reflectance coating is placed on the echo area 154 of book sheet 146 first surfaces 148.First reflecting bundle 166 has been determined the 3rd incident angle θ 5 with respect to the normal of the first surface of book sheet 146.Because the first surface 148 and the second surface 150 of book sheet are parallel to each other basically, therefore, the 3rd incident angle θ 5 is substantially equal to the first reflection angle θ 4.

Thereby first reflecting bundle 166 that second polarization arranged obtains second reflecting bundle 168 of second polarization and has determined the normal second reflection angle θ 6 with respect to the first surface 148 of book sheet 146 from echo area 154 reflections of first surface 148, according to reflection theorem, the second reflection angle θ 6 equals the 3rd incident angle θ 5.Second reflecting bundle 168 is transferred to the second output face port one 44 by book sheet 146, and incides in this port on second refracting sphere 158 of second surface 150 of book sheet 146.Second reflecting bundle 168 has been determined the 4th incident angle θ 7 with respect to the second surface 150 of thin slice 146.Because first, second surface 148,150 is parallel to each other basically, therefore, the 4th incident angle θ 7 is substantially equal to the second reflection angle θ 6.Thereby the 4th incident angle is substantially equal to the first reflection angle θ 2.

Second reflecting bundle 168 with the second output face port one 44 near second refracting sphere 158 refraction of second surface 150, thereby obtain second polarisation beam 54 of second polarization.This polarisation beam is left the second output face port one 44 with the second output angle φ 2 with respect to the normal of second surface 150.Particularly, second polarisation beam 54 is pressed equation

n _InSin θ ₆=n _OutSin φ ₂(3) refraction.Substantially equate with θ 2 that according to equation (1), (3) and θ 6 the second output angle φ 2 is substantially equal to the first incident angle θ 1.Therefore,

polarisation beam

52,54 is parallel to each other basically.

In one embodiment, polarizing coating 164 is suitable for transmitting the P-polarized light that polarization axle is parallel to coating 164 planes.And then coating 164 is suitable for the s polarized light of polarization by reflection axle perpendicular to coating 164 planes.In this embodiment, first polarisation beam 52 is p polarizations, and second polarisation beam 54 is s polarizations.

In one embodiment, reflectance coating 170 is laid along the echo area 154 of the first surface 148 of book sheet 146, thereby obtains high relatively reflectivity.Therefore, most of energy of first reflecting bundle 166 is reflected in second reflecting bundle 168.And then in one embodiment, second antireflecting coating 172 is laid along second refracting sphere 158 of second surface 150.The purpose of antireflecting coating 172 is reflection and enhancing refractions of forbidding in second echo area 158.

In one embodiment, book sheet 146 is made up of hard glass basically, such as, refractive index is about 1.5 basically.Particularly, first and second surfaces 148,150 of book sheet 146 are parallel to each other, and the depth of parallelism is in 0.5 second.As a result,

polarisation beam

52,54 is parallel to each other, and the depth of parallelism is in 0.75 second.Because book sheet 146 is hard basically, therefore, the high depth of parallelism of

polarisation beam

52,54 is not subjected to the influence of external vibration.

Therefore, clearly, this polarization beam apparatus 50 is compared with existing polarization beam apparatus, has many good qualities.Particularly, since the depth of parallelism of

output polarization bundle

52,54 mainly by the depth of parallelism decision on first and

second surfaces

148 and 150 of book sheet 146 and since the depth of parallelism of existing beam splitter decide by the adjustment of the device that is installed separately, therefore, the

output beam

52,54 of the depth of parallelism that can provide much larger than existing beam splitter can be provided beam splitter 50.And beam splitter 50 is not needing complicated adjustment program change can realize so high depth of parallelism.Moreover because the size of beam splitter 50 is not subjected to the influence of foeign element basically, beam splitter 50 always can obtain substantially parallel output bundle 52,54.At last, beam splitter is two-way, therefore can be used for producing a plurality of output beams from an input beam, also can be used for a plurality of input beams are combined into an output beam.

Referring now to Fig. 5, it has diagrammatically described an embodiment of the dispersive optical element 62 of light filter 30 in more detail.Element 62 comprises diffraction grid 232, and it is fixed on the chromatic dispersion installation elements 234.In one embodiment, this installation elements 234 is prisms 234.Element 62 is suitable for receiving the

polychrome input beam

52,54 on the input face 68 and obtains corresponding a plurality of beamlet 38, and beamlet 38 leaves from the output face 69 of element 62, and emergence angle φ r is relevant with wavelength.Grating 232 is suitable for providing the dispersive optical element 62 of first dispersion characteristics, thereby prism 234 is suitable for providing dispersive optical element 62 gratings 232 of second dispersion characteristics and the dispersive optical element 62 that prism 234 combinations provide the combination dispersion characteristics of having improved thermal stability.

As shown in Figure 5, in one embodiment, the grating 232 of dispersive optical element 62 comprises a normally flat substrate 230,230 wide surface 238; The fluting layer 240 of one fluting face 242 makes fluting layer 242 extend from the surface 238 of substrate 230.Fluting face 242 comprises many narrow grooves 244, and these grooves are illustrated among Fig. 5 in the mode of exaggeration.S is separately at interval by the groove of relatively little plane surveying along substrate 230 for these grooves 244.Fluting face 242 is reflexive in essence, makes the function of grating 232 as reflection device.

In one embodiment, the common reproduction technology of grating 232 usefulness is made, and makes the mould that obtains from master grating be used for imprinting and copying grid 232, duplicates the fluting face 242 that grid 232 have a plurality of parallel slots.For fear of the strongest relevant maximum value (at this moment be the zero level that do not have optical dispersion) relevant with grating 232 is arranged, grating 232 preferably is carved into the first order (m=1).There is an angle on the plane of the surface of each groove 244 and substrate 236.But the grating that uses in other embodiments, other type also is suitable.For example, non-etched diffraction grating, holographic grating, transmission grating etc. also can use.

In preferred embodiment, diffraction grating 232 is suitable for the mode diffraction light same with common diffraction grating, so that obtain the dispersive optical element 162 of first dispersion characteristics.Diffraction grating 232 is suitable for changing that free space wavelength λ f (wavelength that promptly records in a vacuum) to be arranged and the incident angle with respect to the diffraction grating plane is arranged be the direction of the incident beam of θ 1, make that each output beam has diffraction angle m according to the equation of discussing below (6).Because preferably grating is carved into the first order, therefore, for the ratio of m=-1 diffraction utmost point diffraction light energy with the incident light energy, claims that again diffraction efficiency is strengthened.

As shown in Figure 5, the prism 234 of dispersive optical element 62 comprises a plurality of normally flat planes of refraction 250.Plane of refraction 250 comprises input face 68, and output face 69 and installed surface 256 make entering angle α be transfused to face 68 and installed surface 256 is determined, emergence angle γ is determined by output face 69 and installed surface 256.The input face 68 of prism 234 makes

light beam

52,54 can enter the optical dispersion device as the input port 260 of dispersive optical element 62.The output face 69 of prism 234 makes a plurality of beamlets 38 leave from the optical dispersion device with the direction relevant with wavelength as the output port 264 of dispersive optical element 62.Prism 234 usefulness transparent materials are made its refractive index n _pRelevant with the light wavelength of transmission therein.

As shown in Figure 5, in preferred embodiment, grating 232 is directly installed on the installation surface 256 of prism 234, thereby obtains the dispersive optical element 62 of diffraction surfaces 258.Grating be positioned at prism 234 installation surface 256 near, make that the substrate 236 of grating 232 is parallel with the fixed surface 256 of prism 234 basically.The fluting face 242 of grating 232 is positioned near the fixed surface 256, makes that fluting face 242 is diffraction surfaces 258.The thickness of facing a charge mutually is that the transparent epoxy book layer of T is inserted between grating 232 and the prism 234 in the mode of direct seamless applying, makes the fluting face of grating 232 and the fixed surface 256 of prism 234 be bonded together.Epoxy 268 the most handy refractive indexes are substantially equal to the refractive index materials of prism 234, avoid light from fixed surface 256 reflections like this.

Though the grating 232 that separately forms on the prism 234 of being installed in is as shown in Figure 5 used in the preferred embodiment of dispersive optical element 62, clearly, in other embodiments, also can provide a kind of diffraction surfaces of accommodation.For example, in one embodiment, but the surface 256 of the prism 234 method fluting that also the fluting face of the grating 232 of image pattern 5 is the same.

Fig. 6 referring now to the combination dispersion characteristics of describing dispersive optical element 62.In this simple case, monochromatic input beam 270, its free space wavelength is λ f, the input face 68 of directive dispersive optical element 62.Input beam 270 is changed direction by element 62 then, and making has the output bundle of identical free space wavelength λ f to penetrate from the output face 69 of element 62, and its emergence angle with respect to output face 69 normals is φ r.

As shown in Figure 6, input beam 270 is the incident medium 274 of ni by refractive index, and as air, the input face 68 of directive prism 234 is β 1 with respect to first incident angle of the normal of the plane of incidence 68.When arriving input face 68, input beam 270 produces the first refraction bundle 276 through refraction, is β r with respect to the refraction angle of the normal of input face 68, has

n _isinβ _i＝n _psinβ _r (4)

As shown in Figure 6, deflecting light beams 276 is by the grating 232 of prism 234 directives along fixed surface 256 placements.Light beam 276 directive fixed surfaces 256 are determined the second incident angle θ i with respect to the normal on fixed surface 256 planes.θ i is relevant with the entering angle α of β r and prism, according to geometric equation, has

θ _i＝α-β _r (5)

As shown in Figure 6, diffraction grating is diffracted into light beam 276 diffracted beam 278 that enters prism 234 by fixed surface 256 once more.According to well-known diffraction grating equation, (order of diffraction m=-1) in this case, this The Representation Equation is:

S (sin θ _i+ sin θ _mThe λ of)=- _f/ n _p(6) diffracted beam 278 has been determined the diffraction angle m with respect to fixed surface 256 normals.

As shown in Figure 6, diffracted beam 278 is advanced by prism 234 before output face 69 outgoing of prism 234, therefore, determines the 3rd incident angle φ i with respect to output face 69 normals.Incident angle φ i and θ m and prism to leave angle γ relevant, the meeting geometric equation:

φ _i=γ-θ _m(7) diffracted beam 278 reflects in output face 69, thereby obtains output beam 272, satisfies equation:

n _pSin φ _i=n _rSin φ _r(8) here, n _γIt is near the refractive index of the medium the prism 234 outside output surfaces 254.In preferred embodiment, near the medium the output face 69 is an air.

According to equation (4)-(8), clearly, emergence angle φ _γWith the first incident angle β i, the refractive index n p of prism, the entering angle α of prism, the well width S of grating, the free space wavelength λ f that leaves angle γ and output beam of prism is relevant.This has explained that

light beam

52,54 chromatic dispersions among Fig. 5 why become a plurality of monochromatic beamlets, and each monochromatic beamlet has unique emergence angle φ _γBut, owing to usually varying with temperature, np and S change, if there is not now the compensation design feature of dispersive optical element 62 in greater detail, emergence angle φ r has substantial variation probably.

In order to reduce the temperature variant variation of emergence angle φ r of light-scattering component 62, in one embodiment, the dispersive optical element 62 of employing makes heat cause that the influence of the variation of np is reduced by the influence that thermal conductance causes the S variation.Especially according to equation (4)-(8), the selected material of light-scattering component 62 usefulness makes, and makes the refractive index of prism 234 provide the temperature variant speed of firing angle φ r (d φ with respect to the speed (dn/dT) of temperature variation and the groove wide temperature variant speed in interval (ds/dT) of grating 232 _r/ dT) less relatively.

For example, in one embodiment,, make the grating 232 that adopts that desired ds/dT value be arranged by on fluting layer 240, applying the method with the stress of temperature correlation.This stress can be the result of dispersive optical element 62 thermal expansions.More particularly, the material of the fluting layer 240 that the ds/dT of fluting layer 240 can be by selecting suitable thermal expansivity (CTE) is selected.Ds/dT also determines by the thermal stress that acts on the fluting layer 240.For example, because fluting layer directly is bonded on the substrate 236, therefore, substrate 236 can be used for cross-notching layer 240 according to the CTE of substrate 236 and apply thermal stress.Because fluting layer 240 is directly bonded on the epoxy 268, epoxy 268 can come the cross-notching layer to apply thermal stress according to the CTE of epoxy.In addition because prism 234 is adhered on the epoxy 268, prism 234 can be used for by epoxy 268 indirectly the cross-notching layer apply thermal stress, the thermal stress that is added in fluting layer 240 depends on the modulus of elasticity of epoxy 268, the CTE of the thickness of epoxy 268 and prism 238.

In one embodiment, the wide S in the groove of grating 232 interval varies with temperature and maintains a constant relatively value.This is to have the material of the substrate 236 of relatively little CTE to realize by selection.In one embodiment, epoxy 268 is highly elastic materials that suitable thickness is arranged, and therefore, grating 232 separates with the thermal expansion of prism 234 basically.The material of prism 234 can be selected relatively little CTE material.

In one embodiment, form dispersive optical element 62, make the ds/dT of grating 232 be substantially zero and the dn/dT of prism is essentially non-zero.In order to reach thermal compensation, the dispersive optical element 62 of formation has suitable α, γ and np value, makes to be essentially the dn/dT of non-zero to φ _γInfluence do not exist basically by equation (4)-(8).For example, if the refractive index n p of prism increases, then press equation (4), refraction angle β r reduces, and presses equation (5), and incident angle θ i reduces.Correspondingly, press equation (6), diffraction angle m is increased, press equation (7), incident angle φ i reduces.Select φ I reduce make np relative constant with the product of sin φ i, thereby feasible according to equation (8), φ r remains unchanged basically.

Therefore, the professional and technical personnel can be appreciated that, the very big d φ that freely makes is arranged when design dispersive optical element 62 _γ/ dT reduces.In one embodiment, the material of dispersive optical element and shape are selected to such an extent that the influence of the dn/dT of the influence of ds/dT of non-zero and non-zero is offseted.In another embodiment, to adopt be that zero the ds/dT and the dn/dT of basic non-zero make that φ r is constant relatively when changing np to dispersive optical element substantially.

Thereby dispersive optical element 62 can be with than the more desirable mode dispersed light of the dispersive optical element of prior art.Offset by the wide at interval influence of groove that the influence of the relevant refractive index of the heat of prism is relevant with the heat of grating 232, the emergence angle φ r of dispersive optical element 62 is insensitive to variation of temperature.And then, adopt in one embodiment dispersive optical element 62 make grating 232 groove at interval wide S to the change relative insensitivity of temperature with make temperature change influence the refractive index n p of grating 232 greatly.Yet in this embodiment, the formation of prism 234 and shape are selected to such an extent that make the emergence angle φ of beamlet 38 _γBasically irrelevant with the temperature of dispersive optical element 62.

Another embodiment of the dispersive optical element 62 of light filter 30 is described referring now to Fig. 7.In this embodiment, the incident of the diffraction grating 332 of the dispersive optical element of employing by reducing to enter and leave dispersive optical element 62 and the angle of diffracted beam provide improved on the whole efficient.

As shown in Figure 7, element 62 is similar to the element 62 of Fig. 5.Particularly element 62 includes input face 68, the prism 334 of output face 69 and stationary plane 356.Element 62 also comprises and is similar to the same diffraction grating of Fig. 5 grating 332, so that a diffraction surfaces 336 to be provided.Particularly diffraction grid 332 are installed in and make on the stationary plane 336 of prism 334 and penetrate 332 diffraction of

light beam

52,54 complete diffracted grid on prism 334 input faces 68, thereby obtain leaving the beamlet 38 of output face 69.Moreover the element 62 of employing has previous element 62 described thermal compensation characteristics in Fig. 5, varies with temperature basically dispersion characteristics uniformly thereby provide.But as following meeting in greater detail, the element 62 of Fig. 6 is limited in the input and output beam channel in the prism 334, makes that the diffraction efficiency of grating 332 is improved.

As shown in Figure 7, adopt prism 334, make

light beam

52,54 enter the input face 68 of prism 334,356 transmission in prism along input beam passage 346 to stationary plane.Particularly, each input beam passage 346 comprises first length 310 that extends to the reflection position 310 that is positioned at prism 334.Each input beam passage 346 also comprises second length 312 that extends to diffraction surfaces 336 from reflection position 311, and the incident angle that makes

light beam

52,54 limit with respect to diffraction surfaces 336 normals is θ i.

In one embodiment, at reflection position 311,

light beam

52,54 reflects, and consequently causes total internal reflection (TIR).Particularly, first length 310 of each input beam 346 is extended first outside surface 318 of prism 334, defines the incident angle ki with respect to first surface 318 normals.Adopt prism 334, make incident angle ki greater than by sin ^-1(n _p/ n _Out) critical angle on first surface 318 that limited, here, n _OutBe near the refractive index of the prism 334 external agencys first surface 318, np is the refractive index of prism 334.

As shown in Figure 7, first length 310 of each input beam passage 346 is extended to output face 69 from input face 68.When arriving output face 69,

light beam

52,54 total reflections there, thus changing direction along second length 312 of input beam passage 346, this second length 312 is extended to stationary plane 356 from output face 69.

Adopt prism 334 make beamlet from diffraction surfaces 336 in prism 334 along output beam passage 348 from diffraction surfaces 336 to output face 69 transmission.Each output beam passage 348 comprises first length 314, and this first length is extended to output face 69 from stationary plane 356 by the direction that diffraction angle m is limited, and the diffraction angle m of relative diffraction surfaces 336 presses equation (6) and determines.First length 314 of each output beam passage 348 further defines the incident angle φ i with respect to output face 69.The incident angle φ i that is output each output beam passage 348 qualification on the face 69 makes total reflection does not take place less than critical angle.In one embodiment, coat antireflecting coating, thereby increase beamlet 38 does not have

light beam

52,54 by the transmission of output face 69 unhelpful total reflection along the output face 69 of prism 332.

Adopt element 26, make second length 312 of each input beam passage 346 and first length 314 of each output beam passage 348 limit a relative little angle Ω.In one embodiment, Ω is less than 5 degree.Because the angle that angle Ω is provided less than the prior art device, diffraction grid 332 can improve diffraction efficiency.And then, since

light beam

52,54 and beamlet 38 respectively by the input and

output face

68,69 that separates on the space into and out of element,

light beam

52,54 and beamlet 38 seldom be subjected near the influence of assembly.

For example, in one embodiment, half-wave plate 60 is placed near the input face 68 of element 62, thereby, be also placed on the passage of light beam 54, as shown in Figure 7.But because beamlet 38 leaves output face 69 and transmit with the zone that input face 68 separates basically on the edge, beamlet 38 does not enter half-wave plate 60.Therefore, beamlet 38 has at least one not influenced by half-wave plate 60.

In one embodiment, adopt element 62, make in the output face 69 of prism 334, at least one light beam of

light beam

52,54 and have the sub-light 38 of ellipse garden cross sectional shape to overlap each other.Because

input beam

52,54 has a width that extends, it is along there being first incidence zone 320 of width W 1 to be mapped to output face 69.Equally, because output beamlet 38 has a width that extends, it is that second incidence zone 322 of W2 is mapped to output face 69 along width.Because the angle Ω between

input beam

52,54 and the output beamlet 38 is quite little, overlap in second incidence zone 322 and first incidence zone 320, as shown in Figure 4.

Therefore, can be appreciated that the dispersive optical element 62 of Fig. 7 has the advantage of raising by efficient.This advantage is by realizing when the output beam passage 346,348 of the input of low-angle Ω at diffraction surfaces 336 upper limit phasings.And diffraction surfaces 336 has improved the diffraction efficiency of grating 332.For example, if the Ω angle is reduced to 5 degree from 15 degree, the diffraction efficiency rate of diffraction grid 332 can improve 10%.And then the realization of this advantage does not need

input beam

52,54 and output beamlet to pass through very close to ground each other in prism 334 outsides yet.Therefore, element 62 can use with half-wave plate 60, makes half-wave plate influence light beam 54 and does not influence beamlet 38.

Referring now to Fig. 8, it in more detail diagram the preferred embodiment of the light filter 30 of 3 Fig. 1 is described.Device 30 symmetries constitute makes that input block 36 and output block 48 are same basically.Device 30 comprises first beam splitter 50 of input block 36 and the second similar substantially beam splitter 51 of a part that forms output block 48.As previously discussed, the beam splitter 50 of the polarization converter of input block 36 receives input beam 32 and input beam 32 is divided into p polarization and s

light beam

52 and 54 at the input face port one 40 of input face 56, and

light beam

52,54 substantially parallel ground leave the output face port one 42,144 of beam splitter 50 respectively

And then in this embodiment, the bundle composition element 114 of the depolarization converter 110 of output block 48 comprises beam splitter 51.Beam splitter 51 is placed with opposite way, makes to exist the s light beam 106 of half-wave plate 112 to enter the second output face port one 44 of beam splitter 51, and leaves the first output face port one 42 that the first p light beam of restrainting composition element 100 enters beam splitter 51.Because beam splitter 51 is two-way, light beam 106,108 is parallel basically and is respectively s polarization and p polarization, thereby the effective beam combination 106,108 of beam splitter 51, thereby obtain leaving the output beam 34 of beam splitter 51 input face port ones 40 in the mode of basic collimation.

In Fig. 8 embodiment, device 30 also comprises the dispersive optical element 62 and the second basic the same dispersive optical element 61 that forms output block 48 parts of input block 36.As mentioned above, the dispersive optical element 62 of input block 36 receives

p light beam

52,54 on the input face 68 of element 62.And element 61 chromatic dispersion light beams 52,54, thereby the beamlet that obtains separating on the space 38 and leave the output face 69 of element 62.

In this embodiment, 48 the first light beam composition element 100 comprises second dispersive optical element 61 on the output block.Element 61 opposed member, 62 symmetrical placement are also arranged to such an extent that to make the input face 102 of the first light beam composition element 100 are output faces 69 of second dispersive optical element 61.Equally, the output face 104 of the first light beam composition element 100 is input faces 68 of element 61.With opposite way work, element 61 reconfigures and desiredly enters the beamlet 42 of output face 69 and reconfigure the input face 68 that beamlet 42 forms beam combinations 106,108 and leaves element 61.

In the embodiment of Fig. 8, concentrating element 70 includes the heart convergent lens 71 far away of focal length and collimating element 90 and comprises the convergent lens 91 the same with lens 71.

Lens

71 and 91 are put score and are taken leave of dispersive optical element 62,61 and be substantially equal on the position of the focal length of

lens.Lens

71 and 91 are also placed in branch and take leave of on the position of focal length that the screen 80 of filter part 46 is substantially equal to

lens

71,91.

The result, the desired beamlet 42 that enters lens 71 defines respectively with the desired beamlet 42 that leaves lens 91 to be dispersed and the convergent beam passage, make angular-spread beam passage 96 geometric configuration basically with the geometric match of convergent beams passage 98, represented as Fig. 3.Because beamlet 42 leaves collimating element 70 along convergent beams passage 98 (its participant dispersion channel 96 on geometric configuration is similar), beamlet 42 is effectively combination in dispersion element 61, thereby obtains composite light beam 106,108, leaves element 62b with substantially parallel direction.

Therefore, can be appreciated that light filter 30 has provided improved filtering characteristic.Particularly, because that device 30 is divided into input beam is a plurality of desired, the beamlet that separates with a plurality of beamlets of not wanting spatially, device 30 can be by the wavelength components that stops that in essence beamlet that beamlet separates is decayed and do not wanted in the input beam.And, because desired beamlet is linear polarization state, so they are by dispersion element 62 and 61 diffraction efficiently.So device 30 can be by the desired wavelength components of input beam and the spectrally resolved ability that is improved with high percent of pass, even make that the wavelength difference of wavelength component is very little, desired wavelength component also can make a distinction with the wavelength component of not wanting.

To recognize also that light filter 30 provides varies with temperature basicly stable filtering characteristic.Particularly because dispersion element 62 has dispersion characteristics with temperature stabilization, thereby the beamlet 38 that leaves dispersion element 62 seldom may be acted upon by temperature changes.By using beam splitter 50, the thermal stability of device 30 further is enhanced the Temperature Influence that its performance is not changed basically.

Referring now to Fig. 9, a light filtering system 120 according to another embodiment of the present invention has been described its diagram.System 120 comprises first and second smooth filter 30j and the 30k, and they are substantially similar to the light filter 30 of Fig. 8.Device 30j and 30k be the structure arrangement to stack preferably, thereby they are adjacent one another are.Adopt device 30j and 30k to receive first and second input beam 32j and the 32k respectively, each light beam all has desired and wavelength component that do not want.Device 30j and 30k obtain first and second output beam 34j and the 34k that each wants wavelength component that comprise separately at last with the light filter of image pattern 2 and Fig. 3 same mode filtered beam 32j and 32k.

As shown in Figure 9, system 120 comprises the first and second polarization beam apparatus 50j that make with normal transparent book sheet 124 and the first polarization beam apparatus subsystem 122 of 50k, makes element 50j and 50k forever aim at each other.In addition element 50j and 50k structurally be the same with the element 50 of Fig. 4 on the function.

The first light beam 32j of the first input face port one 40j that enters subsystem 122 is by subsystem 122 beam splitting, make the output beam 52j of p polarization leave the first input face port one 42j of subsystem 122, the second output beam 54j of s polarization leaves the second output face port one 44j of subsystem 122.The first and second light beam 52j and 54j are to transmit with the substantially parallel direction of first input beam 32j collimation basically.The second input beam 32k of the second input face port one 42k that enters subsystem 122 simultaneously is by subsystem 122 beam splitting, so the 3rd output beam 52k with p polarization leaves the 3rd output face port one 42k of subsystem 122, the 4th output beam 54k of s polarization leaves the 4th output face port one 44k of system.The third and fourth output bundle 52k, 54k are to transmit with the substantially parallel direction of second input beam 32k collimation basically.

As shown in Figure 9, system 120 comprises half-wave plate 60j and 60k.Half-wave plate 60j and 60k place to such an extent that receive respectively from s polarisation beam 54j, the 54k of subsystem 122 and for they provide p polarization.

As shown in Figure 9, this system comprises that also reception is from the 52j of polarization beam apparatus subsystem 122 and 52k with from the p polarisation beam 54j of half-wave plate 60j, 60k, the optical dispersion subsystem 126 of 54k.As will be in greater detail below in conjunction with figure, subsystem 126 comprises the first and second dispersive optical element 62j, the 62k of the single prism 434 of common use, and wherein, 62j, 62k are substantially similar to the dispersive optical element 62 of Fig. 8.The first dispersion element 62j reception sources is from light beam 52j, the 54j of the first input beam 32j and provide the p polarization that separates on corresponding a plurality of space monochromatic beamlet 38j.In addition, the second dispersion element 62k reception sources is from light beam 52k, the 54k of the second input beam 32k and provide the p polarization that separates on corresponding a plurality of space monochromatic beamlet 38k.

Figure 10 has described the embodiment of optical dispersion subsystem 126 of the light filtering system 120 of Fig. 9 in more detail.Subsystem 126 comprises first and second dispersive optical element 62js, the 62k similar substantially to the dispersive optical element 62 of Fig. 7.In one embodiment, subsystem 126 comprises a prism 434 and a diffraction grating 432, and they are suitable for providing input face port 68J, 68K, output face port 69j, the 69k that separates and the diffraction surfaces port 442,443 that separates separately.Light beam 52j, 54j are transfused to face port 68j and receive and diffracted port 442 diffraction, thereby the beamlet 38j that leaves output face port 69j is provided.In addition, light beam 52k, 54k are transfused to face port 68K and receive and diffracted port 443 diffraction, thereby the beamlet 38k that leaves output face outlet 69k is provided.

It is understandable that this optical dispersion system 126 has many advantages.Particularly subsystem 126 makes dispersion element 62j, 62k have the diffraction efficiency of improved thermal stability and improvement.Because look uses same prism jointly with element 62j, 62k, they can be aligned with each other in more reliable mode.Moreover, because all elements of subsystem 126 stick together the unlikely during use misalignment of subsystem 126 rigidly.In addition, because subsystem 126 comprises single grating 432, the dispersion element 62j of subsystem 126, the aligning of 62k are further simplified, and therefore, the manufacturing cost of subsystem 126 are reduced.

With reference to Fig. 9, the optical dispersion device 30j of system 120 and 30k include a pair of lens 71j, 91j and 71k, 91k, and they and a pair of lens the 71, the 91st of Fig. 8 are the same.Lens 71j receives beamlet 38j, and beamlet 38j has the desired beamlet 42j from dispersive optical element 62j.In addition, lens 71k receives the beamlet 38k that contains desired beamlet 42k from element 62k.Lens 71j, 71k separately accumulate in beamlet 38j, 38k respectively on the one common focal plane.And then lens 91j and 91k collimate desired beamlet 42j, the 42k that leaves filtering subsystem 127 respectively separately.As shown in Figure 9, system 120 also comprise for allow more than first and second desired beamlet 42j, 42k select by and stop more than first and second beamlet 44j, 44k that does not want by filtering subsystem 127.This subsystem comprises an opaque screen 125 that more than first and second hole 86j, 86k arranged, and each hole is similar to a plurality of holes 86 of the screen 80 of Fig. 3.Screen 125 is placed on the focal plane of lens 71j and 71k, makes hole 125 and a plurality of first beamlet 42j that wants coincide, and hole 125 coincides with a plurality of second beamlet 42k that wants.Like this, the beamlet 44j, the 44k that do not want are stopped that by screen 125 desired beamlet 42j, 42k allow to leave screen 125, thus directive lens 91j and 91k.

As shown in Figure 9, system 120 also comprises the second optical dispersion subsystem 128, and it receives beamlet 42j, the 42k that leaves lens 91j and 91k.Subsystem 128 is the same with subsystem 126, comprises dispersive optical element 61j and 61k.Subsystem 128 with top Fig. 8 in the opposite mode described arrange, make the dispersive optical element 61j of subsystem 128 and 61k receive beamlet 42j and 42k respectively and their form p polarization combination light beam to 106j, 108j and 106k, 108k with the effective and efficient manner combination.And then light beam 106j and 106k directive half-wave plate 112j and 112k respectively, thereby obtain light beam 106j, the 106k of s polarization.

As shown in Figure 9, system 120 also comprises the second polarization beam apparatus subsystem 129, and it receives s light beam 106j, the 106k that leaves p light beam 108j, the 108k of the second optical dispersion subsystem 128 and leave half-wave plate 112j, 112k respectively.Subsystem 129 is the same with subsystem 122, comprises second polarization beam apparatus 51j and the 51k.This subsystem with top Fig. 8 in the opposite way arrangement described make the polarization beam apparatus of subsystem 129 receive beam combination respectively to be combined to form output bundle 34j and 34k to 106j, 108j and 106k, 108k and with effective and efficient manner.

With reference to Figure 11 and 12, their diagrams have been described other embodiment of light filtering system 120.In these embodiments, light filtering system 120 comprises first polarization beam apparatus 122, half-wave plate 60j, 60k and the first optical dispersion subsystem 126, and they are divided into beamlet 38j, 38k respectively with input beam 32j, 32k.The system 120 of Figure 11 and Figure 12 also comprises filtering subsystem 127, the second optical dispersion subsystem 128, half-wave plate 112j, 112k and second bundle be subsystem 129 along separate routes, and they are chooser light beam 42j, 42k and beamlet 42j, 42k be combined into output beam 34j, 34k respectively.But, replace the used lens that separate right, Figure 11,120 of 12 systems use single lens 71 focuson light beam 38j and 38k and single collimation lens 91 to collimate beamlet 42j and 42k, therefore, can make system 120 reduce the space.

In the embodiment of Figure 11, input beam 32j, 32k are positioned at each other and leave sizable distance.In order to compensate this displacement, system 120 comprises a beamlet and merges element 130, it receives from the beamlet 38j and the 38k of optical dispersion subsystem 126 and exports beamlet 38j and 38k, make them along adjacent basically beam channel transmission, and then, in order to obtain suitable large space output beam 34j and 34k at interval, system 120 also comprises light beam unwinding members 131, and it receives more than first and second desired beamlet 42j and 42k that are close on the space and exports beamlet 42j and the 42k that quite big displacement is arranged to each other.

As shown in figure 11, beamlet merges element 130 and comprises half-wave plate 132 and polarization beam apparatus 133.Lay half-wave plate 132 leaves optical dispersion system 126 with reception p polariton beam 38j.The beamlet 38j of half-wave plate 132 output s polarizations makes s polariton beam 38j be received by beam splitter 133.Beam splitter 133 is laid to such an extent that make reception from the s polariton beam 38j of half-wave plate 132 with from the p polariton beam 38k of subsystem 126.Beam splitter 133 and the beam splitter 50 of Fig. 4 are the same and are orientated in anti-phase mode so that receive s polariton beam 38j and p polariton beam 38k at the output face port, and export along substantially parallel direction from the input face port.

As shown in figure 11, beamlet unwinding members 131 is placed on the p polariton beam 42k to receive desired s polariton beam 42j and to transmit along adjacent basically beam channel between lens 91 and the optical dispersion subsystem 128.Element 131 is the same with element 130, and it comprises beam splitter 134 and half-wave plate 135.Beam splitter receives beamlet 42j and 42k and output beamlet 42j and the 42k from the output face port of displacement at input face, thereby s polariton beam 42j and p polariton beam 42k are subjected to displacement.The s polariton beam passes through half-wave plate 134 then, thereby obtains the beamlet 42j of p polarization.

As shown in figure 11, in one embodiment, system 120 also comprises first and second optical compensators 136 and 137.Compensator 136 is placed between subsystem 126 and the lens 71, thereby receives beamlet 38j, is placed between lens 91 and the subsystem 128 to receive beamlet 42j and compensate 137.How much differences between the passage of 136,137 couples of beamlet 38J of compensator and the passage of beamlet 38K compensate.

In the embodiment of Figure 12, input beam 32j and 32k advance along adjacent basically beam channel, and the result is that beamlet 38j is adjacent with beamlet 38k basically, therefore allow to assemble beamlet 38j and 38k with lens 71.And then the beamlet 42j and the 42k that leave filter 127 are adjacent one another are, therefore make lens 91 can collimate beamlet 42j and 42k.

In the embodiment of Figure 11 and Figure 12, input beam 32j, the 32k that the intensity distributions 76j at screen 125 relevant with input beam 32j suitably guided removes from the intensity distributions 76k of input beam 32k.For example, if light beam 32j, 32k collimate along the Z axle shown in Figure 11 and 12 like that substantially, then intensity distributions 76k can be made light beam 32j offset along the distribution 76k that Y-axis tilts slightly with respect to 32k along the Y-Z plane.In this case, because 76j and 76k elongate along X-axis, they are forced on the different port of screen.Alternately, if 32j along the X-Z plane inclination, side intensity distributions 76j can move along X-axis with respect to distribution 76k.

Recognize that Fig. 9,11 and 12 light filtering system 120 can have many good qualities.Particularly each of light filtering system 120 all comprises basically first and second smooth filter 30j and the 30ks the same with the improved smooth filter 30 of Fig. 8.Therefore, system be particularly suitable for requirement can be with the fine resolution ability, effectively see through desired wavelength components and stop the occasion of staggered filtering application of two input beams of difference filtering of wavelength component not.And then because a lot of parts of device 30j and 30k are shared, thereby system 120 can arrange compactly to save the space.Moreover beamlet 38k focuses on the 86k of hole because beamlet 38j focuses on hole 86j, and 86j and 86k separate, thereby have reduced the possibility of cross (talk).

Although before declarative description preferred embodiment of the present invention and having pointed out when using this embodiment, very important and novel characteristics of the present invention, but must understand, the pro forma abreviation of the details of described device is replaced and is changed and can accomplished under the situation of spirit of the present invention by those skilled in the art.Therefore, scope of the present invention should not be limited to foregoing description, and should be determined by additional claim.

Claims

1, a kind of to having the light filter that a plurality of input beams of wanting wavelength component and a plurality of not wavelength component carry out filtering, it is characterized in that the light filter comprises:

An input block of on the input beam passage, laying, described input block is divided into a plurality of monochromatic polariton beams with input bundle, these beamlets are along a plurality of beam channels transmission that separate on corresponding spaces, the monochromatic beamlets of described a plurality of polarizations comprise (a) a plurality of corresponding to institute's beamlet of wanting of want wavelength component with (b) a plurality of corresponding to the beamlet of not wanting of not wanting wavelength component.

A filter part of laying on beam channel, described filter part make beamlet decay not, and desired beamlet is passed through; With

An output block of laying receives the beamlet of wanting from filter part, and described output block spatially makes up desired beamlet, thus obtain comprising input beam the wavelength component of wanting through the filtering output beam.

By the described device of claim 1, it is characterized in that 2, input block comprises lays polarization converter to receive input beam, described polarization converter converts input beam to linearly polarized light.

3, by the described device of claim 2, it is characterized in that polarization converter converts input beam at least one p light beam.

4, by the described device of claim 3, it is characterized in that at least one p light beam is included in first and second light beams that transmit on the substantially parallel direction.

5, by the described device of claim 4, it is characterized in that, polarization converter comprises a polarization beam apparatus and a polarization rotator sheet, described polarization beam apparatus provides a p light beam and s polarisation beam, lay the feasible s of reception of described polarization rotator sheet polarisation beam, the polarization axle of described polarization rotator sheet rotation s polarisation beam is to obtain the 2nd p polarisation beam.

By the described device of claim 4, it is characterized in that 6, input block also comprises the dispersive optical element that the first and second p light beam chromatic dispersions is become the monochromatic beamlet of a plurality of polarizations, described dispersive optical element comprises a diffraction grating.

7, by the described device of claim 6, it is characterized in that input block also comprises the concentrating element of reception from a plurality of polarization homogeneous beams of dispersive optical element, described concentrating element focuses on a plurality of polarization homogeneous beams on one focal plane.

By the described device of claim 7, it is characterized in that 8, the described focusing of described gathering element provides an intensity distributions spatially that extend, that separate on spectrum.

9,, it is characterized in that concentrating element will be matched to right having and match the beamlet of wavelength towards the other side, make that being matched to right beamlet intersects each other on the focal plane of concentrating element by the described device of claim 8.

10, a kind ofly it is characterized in that, said method comprising the steps of there being a plurality of input beams of wanting wavelength component and a plurality of not wavelength component to carry out the method for filtering with the output beam that only comprised desired wavelength component:

Input beam is divided into a plurality of monochromatic beamlets of polarization along the beam channel transmission that separates on the space, and described beamlet comprises (a) a plurality of beamlets of wanting corresponding to want wavelength component, (b) a plurality of not beamlets corresponding to the wavelength component of not wanting;

Want beamlet and beamlet are not separated; With

Thereby make up desired beamlet and obtain output beam through filtering.

11,, it is characterized in that separately the step of input beam comprises and converts input beam at least one linearly polarized light beam by the described method of claim 10.

12,, it is characterized in that the step that converts input beam at least one linearly polarized light beam comprises and converts input beam to first and second p light beams by the described method of claim 11.

By the described method of claim 12, it is characterized in that 13, the step of separating input beam also comprises makes the input beam diffraction.

14, by the described method of claim 13, it is characterized in that, the step of input beam diffraction is comprised make at least one linearly polarized light beam by having the dispersive optical element of diffraction grating, make the diffracted optical grating diffraction of at least one linear polarization bundle.

15, a kind of control a plurality of wavelength component are arranged input beam to obtain the light control device of an output beam, it is characterized in that described device comprises:

Be placed on the input block on the incident beam passage, described input block is divided into the monochromatic beamlet of first group of a plurality of polarization along the beamlet channel transfer of separating on corresponding a plurality of spaces with incident beam;

Be placed on the beamlet controller on the beamlet passage, control in the monochromatic beamlets of first group of a plurality of polarization at least one in the relevant mode in space, described beamlet controller provides second group of monochromatic beamlet of a plurality of polarizations; With

Settle an output block, receive the monochromatic beamlet of second group of a plurality of polarization that leaves the beamlet controller, described output block makes up the output beam from second group of monochromatic beamlet of a plurality of polarizations.

16, by the described device of claim 15, it is characterized in that first group of monochromatic beamlet of a plurality of polarizations comprise that (a) is a plurality of and want institute's beamlet of wanting of wavelength component and (b) a plurality of a plurality of beamlets of not wanting of not wanting wavelength component corresponding to input beam corresponding to input beam a plurality of;

The monochromatic beamlet of second group of a plurality of polarization wherein comprises a plurality of desired beamlets; With

Beamlet controller wherein comprises a filter part, and described filter part is decayed beamlet not and passed through desired beamlet.

17, by the described device of claim 16, it is characterized in that, filter part includes the opaque material in a plurality of holes, laying described filter part makes a plurality of beamlets of wanting aim at a plurality of holes, a plurality of beamlets of not wanting are not aimed at a plurality of holes, thereby the institute's beamlet of wanting formation that wherein filter part is left in combination on the output block space comprises the output beam of wanting wavelength component in the input beam.

18, a kind of filtration has first group and second group of a plurality of wavelength component and first group and second group of a plurality of not light filtering system of first and second input beams of wavelength component wanted respectively, it is characterized in that this system comprises:

Be placed on the input block on the first and second input beam passages, described input block is divided into first and second input beams respectively along first group that separates on the space and second group of first group and second group of monochromatic beamlet of a plurality of polarizations that a plurality of beam channels transmit, described first group of a plurality of and second group of monochromatic beamlet of a plurality of polarizations comprise (a) corresponding to first group of the wavelength component of wanting of first and second input beams and second group a plurality of want beamlet with (b) corresponding to first group and second group of a plurality of beamlet of not wanting of the wavelength component of not wanting of first and second input beams

Be placed on the filter part on first and second beam channels, described filter part decay first group and second group of a plurality of beamlet of not wanting and first group and second group of a plurality of desired beamlet are passed through.

Lay an output block, reception is from first group and second group of a plurality of desired beamlet of filter part, thereby described output block spatially makes up first output beam through filtering that first group of a plurality of desired beamlet obtains comprising the wavelength component of wanting in first input beam, thereby described output block spatially makes up second output beam through filtering that second group of a plurality of desired beamlet obtains comprising the wavelength component of wanting in second input beam.

19, by the described system of claim 18, it is characterized in that input block comprises the polarizing beam splitter that first and second input beams is divided into the first and second p light beams and the first and second s light beams.

20, by the described system of claim 18, it is characterized in that, input block comprises the dispersive optical element that produces first group and the second group monochromatic beamlet of a plurality of polarizations, described dispersive optical element comprises the transparency carrier of the diffraction grating that includes first and second diffraction surfaces, and described first and second diffraction surfaces provide first and second groups of polarizations monochromatic beamlet respectively.

21, by the described system of claim 18, it is characterized in that, input block comprises and is placed on first group of optical compensator on the monochromatic polariton beam passage, input block also comprises diffraction element, and to reduce on diffraction element geometric (light path) of first group of monochromatic polariton beam and second group of monochromatic polariton beam poor thereby described optical compensator is regulated the beam channel of first group of monochromatic polariton beam.

22, by the described system of claim 18, it is characterized in that, output block comprises and is arranged on more than first optical compensator on institute's straw cord for bundling up rice or wheat stalks beam channel, output block also comprises a diffraction element, thereby described optical compensator is regulated first group of a plurality of light of wanting beamlet and reduced on diffraction element first group of a plurality of beamlet and second of wanting from a plurality of geometric optical path differences of wanting beamlet.