DE4333429A1 - Device having a focusing optical grating for demultiplexing and/or multiplexing and a method for producing such a grating and for operating such a device - Google Patents

Abstract

In the device, the optical grating (1) for demultiplexing and/or multiplexing is constructed in such a manner that it optically images a specific spatial point (10) and another specific spatial point (20) on one another in a specific diffraction arrangement (k1) at a specific centre wavelength ( lambda 1) and optically images a further spatial point (30) and the other spatial point (20) on each other in a further diffraction arrangement (k2) at a further centre wavelength ( lambda 2). This permits wavelength region changeover and channel space changeover (channel spacing changeover, channel separation changeover). A programmable device is obtained by using a reversible optical recording material on which the grating (1) can be recorded. <IMAGE>

Description

The invention relates to a device with a focus Renden grid according to the preamble of claim 1 and a method for producing such a grid and to operate such a facility.

Facilities of the type mentioned are known and are used for optical transmission links for the transmission of many opti shear wavelengths required. These well-known facilities are to be demultiplexed and / or multiple xenden wavelengths constructively so that they only can be used for these wavelengths.

The object of the invention is to provide a device for the aforementioned Provide kind that at least with regard to the demul tiplexing and / or multiplexing wavelengths one in Compared to the known facilities, wider use possible offers.

This task is carried out in the characterizing part of the Features specified claim 1 solved.

The device according to the invention can differ for two their center wavelengths grouped discrete optical waves lengths can be used.

A general advantage of the device according to the invention is that a wavelength range switch and / or wavelength channel distance switching and one per grammable facility is enabled, so that a  device according to the invention by switching with an op table switches or by programming to different Can adapt application purposes.

The focusing optical grating of an inventive The device is preferably a stigmatic image Grid (claim 2), wherein a stigma is particularly advantageous table-imaging grid according to claim 3.

With this advantageous grid one advantageously obtains a device according to the invention, the pure wavelength switching between ranges is possible if the one diffraction order k₁ is chosen equal to the further diffraction order k₂ (Claim 4). In this case it applies to different mids wavelengths and l that the channel spacing dl with respect the center wavelength λ₁ and the channel spacing λ₂ with respect the other center wavelength λ₂ are the same size, and for λ₀ and m applies

λ = k (λ₂-λ₁)
m = λ₁ / (λ₂-λ₁),

where k is the same for both center wavelengths λ₁ and λ₂ Diffraction order is. The channel distance is the distance between neighboring discrete wavelengths.

A device according to the invention, in the pure channel state switching is enabled can be obtained if a center wavelength λ₁ equal to the other center world lenlength λ₂ is selected (claim 5). In this case the a diffraction order k1 unlike the other diffraction order k₂ selected, is the channel spacing for one Beu order k1 different than the channel spacing for the other Diffraction order k2. It applies

¬₀ = (k₂-k₁) · λ
m = k₁ / (k₂-k₁),

where λ the same for both diffraction orders k₁ and k₂ Center wavelength is.

A device for demultiplexing expediently has a switching device according to claim 6, the advantageous switching between different wavelengths areas or channel spacing.

A device for multiplexing can be a switching device according to claim 7, which advantageously also switching between different wavelength ranges and / or channel spacing.

An optical switching device is particularly advantageous according to claim 8, since with such a switching device Optical grids can be easily produced holographically is. Used for holographic recording of the grid reversible optical recording material used one advantageously programmable according to the invention Facilities.

Further preferred and advantageous embodiments of the Device according to the invention go from claims 9 and 10 out.

A device according to the invention, in which the grid is advantageous is liable to be registered, is apparent from claim 11. A particularly advantageous embodiment of this device is a programmable device specified in claim 12 ben is. Preferred and advantageous embodiments of the Programmable devices are in claims 13 and 14 specified.

As in a device according to claim 11 or 12, the grid can be generated advantageously is specified in claim 16  ben, of the preferred and advantageous embodiments in claims 17 to 18 are given.

Claim 20 gives a preferred method of operating a device according to the invention.

The invention is described in the following description of the figures explained in more detail by way of example. Show it:

Fig. 1 is a plan view of an inte grated on a substrate embodiment of a erfindungsge MAESSEN means,

Fig. 2 is a geometrical figure that ver the basic stigmatically designed diffraction grating of the example of Fig. 1 underlying construction principle ver.

In the example of FIG. 1, a layer waveguide 5 is formed on the surface 901 of a substrate 90 with an edge 51 running along a straight line 100 and a curved edge 52 opposite this edge 51 , on which a focusing diffraction grating 1 is formed.

The grating 1 is designed so that it maps a certain main point 10 of the room and another certain main point 20 of the room in a certain diffraction order k 1 at a central wavelength λ 1.

For this central wavelength λ₁ grouped discrete optical wavelengths λ₁₁ to λ₁₄, the grating 1 forms the main point 10 at each discrete wavelength λ₁₁, λ₁₂, λ₁₃ or λ₁₄ and one of these discrete wavelengths λ₁₁, λ₁₂, λ₁₃ or λ₁₄ individually assigned discrete 21 , 22 , 23 and 24 from each other. The discrete main room points 21 , 22 , 23 and 24 are grouped around the other main room point 20 .

The grating 1 can be operated for these discrete wavelengths λ₁₁ to λ₁₄ both as a demultiplexer and a multiplexer.

If the grating 1 is operated as a demultiplexer, the grating 1 is illuminated from the main room point 10 in a certain direction r 1 with the discrete wavelengths λ 1 to λ 1 tet which are distributed from the grating 1 to the discrete spatial points 21 to 24 .

In multiplexing, the grating 1 from the discrete space points 21 to 24 is illuminated with the discrete wavelengths λ₁₁ to λ₂₄ individually assigned to these spatial points, which are collected by the grating 1 in the main space point 10 .

In addition, the diffraction grating 1 is designed such that the grating for further discrete optical wavelengths λ₂₁ to λ₂₄, which are grouped by a certain further center wavelength λ₂, in a further diffraction order k₂ at the other center wavelength λ₂ one of the one and the other main spatial point 10 and 20 different other main room point 30 and the other room main point 20 mapped to each other. The grating at each further discrete wavelength λ₂₁, λ₂₂, λ₂₃ or λ₂₄ forms the other main point 30 and one of these further discrete wavelengths λ₂₁, λ₂₂, λ₂₃ or λ₂₄ individually assigned discrete space point 21 , 22 , 23 to 24 optically from, these discrete spatial points 21 to 24 being grouped around the other main spatial point 20 .

Even at these other discrete wavelengths λ₂₁, λ₂₂, λ₂₃ or λ₂₄, the grating 1 can be used both for demultiplexing and for multiplexing, in which case coupling and decoupling via the further main point 30 instead of the main point 10 .

The grating 1 thus formed can be used independently for both with ten wavelengths λ₁ and λ₂ as a demultiplexer and / or demultiplexer.

In the example of FIG. 1, there is a special feature that the discrete spatial points coincide for both center wavelengths. It is not necessary. It could also be so directed that the discrete wavelengths λ₁₁ to λ₁₄ assigned discrete spatial points are different from the discre th spatial points which are assigned to the other discrete wavelengths λ₂₁ to λ₂₄.

Also, the example is not on four discrete wavelengths and four further discrete wavelengths are limited. The number The discrete wavelengths can be less than or greater than four his. The number of further discrete wavelengths can also be changed be less than or greater than four.

The coupling and uncoupling of the light takes place via entrance and / or exit gates 10 1, 30 1 and 21 1 to 24 1, which are arranged in one and the other main room point 10 and 30 or in the discrete room points 21 to 24 and by one End face of an optical waveguide end section 6 are defined with a longitudinal axis, which are aligned in the direction r₁, r₂ or the directions r₁₁ to r₁₄.

These waveguide end sections 6 are an end section of a waveguide 61 leading to the main space point 10, a waveguide 62 leading to the further main space point 30 and of waveguides 63 to 66 which lead separately to the discrete spatial points 21 to 24 . In these Wellenlei tern 61 to 66 light can be supplied to the layer waveguide 5 or continued from this layer waveguide 5 . These waveguides are integrated on the surface 901 of the substrate 90, for example as a strip waveguide. The waveguides 63 to 66 connect the discrete spatial points 21 to 24 individually to optical devices 41 to 44 , which can be photodetectors in the case of demultiplexing and optical transmitters, for example laser diodes, in the case of multiplexing. These devices 41 to 44 are also arranged on the surface 901 of the substrate 90 .

4 designates an optical switching device arranged on the surface 901 , which is designed such that it distributes light which is supplied via a waveguide 60 formed on the substrate 901 onto the waveguides 61 and 62 or light which is in the waveguide 61 and / or 62 of the switching device 4 is fed into the waveguide 60 couples.

Specifically, the switching device 4 is designed such that it can be switched either only to the waveguide 61 or the waveguide 62 and that it has a switching position in which half of the optical power supplied in the waveguide 60 reaches the waveguide 61 and the waveguide 62 .

Layered optical recording material 7 is applied to the curved edge 52 of the layer waveguide, on which in turn a reflective layer 8 is applied.

Specifically, grating 1 is a stigmatically imaging grating, which is known from Jobin-Yvon: "Diffraction gratings: Ruled and hologra phic", Jobin-Yvon Company Publication (1973) and whose construction principle is indicated in FIG. 2. The grid 1 is formed on a circle 1 ₁ with the one main point 10 as the center point and the radius R. This grating 1 has at a point P on the circle 1 ₁, which meets one of the main spatial point 10 in the particular direction r₁ outgoing light beam axis 100 of a light beam delimited by lines 103 and 104, a grating constant Λ, which by

Λ = λ₀ / n sin (γ₁₃)

given is. 10 means a wavelength determined by the one and further center wavelengths 11 and 12 and by the one and further diffraction orders k1 and k2, for which

λ₀ = k₂ ·, λ₂-k₁ · λ₁

applies. n is the refractive index of the layer waveguide 5 in which the light propagates between the main spatial points 10 , 20 and 30 and the discrete spatial points 21 to 24 and the grating 1 . γ₁₃ is the angle between the light beam axis 100 and a further space r₂ from principal point 30 in the other direction and the outgoing point P on the circle 1 ₁ taken further light beam axis one hundred and first

The three main spatial points 10 , 20 and 30 lie on a straight line 200 . The distance a₁₂ between a main point 10 and the other main point 20 is equal to the radius R of the circle 1 ₁ multiplied by the number m = k₁ · λ₁ / λ₀, ie a₁₂ = R · m. The distance a₁₃ between a main point 10 and the other main point 30 is equal to the radius R divided by this number m = k₁ · λ₁ / λ₀, ie a₁₃ = R / m.

Examples of devices with such a stigmatically imaging grating with pure wavelength range switching are the following:
λ₁ = 1.3 µm, λ₂ = 1.55 µm
k₁ = k₂ = 10, dλ = 4 nm
λ₀ = 2.5 µm, m = 5.2.

Layer waveguide 5 made of glass with n = 1.5, α = 3 °,
ϕ = 120 °, Λ = 11.1 µm and R 6.9 mm
or
Layer waveguide 5 made of InP with n = 3.4, α = 9 °,
ϕ = 120 °, Λ = 5.2 µm, R 1.1 mm.

α is half the opening angle of the light beam emanating from a main point of the room 10 and ϕ the angle between the light beam axis 100 and the straight line 200 .

Examples of a device with such a grating with pure channel spacing switching are:
dλ₁ = 6 nm, dλ2 = 4 nm,
k1 = 8, k₂ = 12, λ₁ = l₂ = 1.55 µm
λ₀ = 6200 nm, m = 2.

Layer waveguide 5 made of glass of n = 1.5, α = 3 °
ϕ = 120 °, DL = 12.6 µm, R 7.8 mm
or
Layer waveguide 5 made of InP with n = 3.2, α = 9 °,
ϕ = 120 °, Λ = 5.9 µm, R 1.2 mm.

The manufacture of devices according to the invention proceeds in exactly the same way as the manufacture of conventional structural elements. Realizations are possible in polymers, InGaAsP / InP, in SiO₂ / Si, LiNbO₃ or in other materials that allow the generation of passive waveguides. The optical switching device 4 can optionally be designed as an electro-optical or thermo-optical switch.

Because of the optical recording material 7 , devices according to the invention can be implemented as holographically programmable devices. Instead of etched or embossed grating 1 occurs in the devices according to the invention photorefractive material or optical recording material into which the grating is written during a holographic exposure.

In the example of Fig. 1, the optical device 4 is set in the programming phase so that half of the incident power reaches the gates 10 ₁ and 30 ₁.

The waveguide 60 couples light from a powerful, tunable light source, for example a color center laser. The wavelength λ₀ is chosen so that the device is optimally suitable for later use.

The grating is generated by operation with the center waves lengths λ₁ and λ₂ tested.

In the operating phase, the switching device 4 is set so that the light arriving in the waveguide 60 reaches either the waveguide 61 or the waveguide 62 .

Programmable devices according to the invention with channel spacing switchover are particularly interesting, since with a fixed geometry of the device, defined by R and m, when generating the grating in general only the center wavelength 11 or λ₂₁ but not the channel spacing can be set.

Examples of such facilities are:
λ₁ = λ₂ = 1.55 µm
dλ₁ = 6 nm, dλ₂ = 4 nm
k₁ = 2, k₂ = 3
λ₀ = 1.55 µm, m = 2.

Layer waveguide 5 made of glass with n = 15, α = 3 °
ϕ = 120 °, Λ = 3.15 µm, R 7.8 mm
or
Layer waveguide 5 made of InP with n = 3.2, α = 9 °
ϕ = 120 °, Λ = 1.48 µm R 1.2 mm.

Programmable devices according to the invention with wavelength Switching between ranges is also possible.

Examples of such a facility are:
λ₁ 1.3 µm, 12 = 1.55 µm
λ₀ = 1.50 µm,
dλ₁ = dλ₂ = 4 nm
k₁ = k₂ = 3
m = 5.2.

Layer waveguide 5 made of glass with n = 1, 5, α = 3 °
ϕ = 120 °, Λ = 6.66 µm, R 6.9 mm
or
Layered waveguide made of InP with n = 3.2, α = 9 °
ϕ = 120 °, Λ = 3.12 µm, R 1.1 mm.

A programmable device according to the invention can be used can be produced as follows:

In the surface of a substrate made of glass, for example, alignment marks are etched, which determine the position of the circle 1 ₁ of the waveguides or waveguide structures or a separating step.

The position of the waveguides is determined by applying a mask, defined for example from Ti, which is relative to the adjustment brands is positioned.

The planar layer waveguide 5 and the strip waveguide 60 to 66 are produced for example by field-assisted ion exchange. The glass of the substrate can, for example, be specially designed for Ag⁺NA⁺.

Thereafter, the substrate is cut along a straight line running obliquely to a substrate edge, which affects the circle 1 ₁, vertically to the substrate surface, so that a corner of the substrate is eliminated. Then a circular cylindrical surface defining the circle 1 ₁ is ground to the substrate, for example with the aid of a swivel table and a lowerable grinding or polishing disc.

The reversible optical recording material 7 is applied to the circular cylinder surface and this material is mirrored, for example by applying a layer of Al or Au, which reflects the light diffracted at the grating to be produced back into the layer waveguide 5 .

Because of the reversible optical recording material 7 , grids can optionally be written or deleted. With the specified materials for the recording material 7 , registration times and deletion times of only a few seconds are possible.

Claims (23)

1. Device for demultiplexing and / or multiplexing several discrete, around a certain optical center wavelength (λ₁) grouped optical wavelengths (λ₁₁ to λ₁₄) consisting of

• - A focusing optical diffraction grating ( 1 ), which in a certain diffraction order (k₁) at the center wavelength (λ₁) has a certain spatial main point ( 10 ) and another specific spatial main point ( 20 ) as well as each with the discrete wavelength λ₁₁, λ₁₂, λ₁₃ and . λ₁₄) the egg main space point ( 10 ) and one of these discrete wavelengths (λ₁₁, λ₁₂, λ₁₃ or λ₁₄) individually assigned discrete spatial point ( 21 , 22 , 23 or 24 ) optically on top of each other, the discrete spatial points ( 21 , 22 , 23 , 24 ) are grouped around the other main point of the room ( 20 ),
• - Wherein at a main room point ( 10 ) an entrance gate ( 10 ₁) is arranged, to which the plurality of gratings from the grating ( 1 ) in the specific direction of diffraction (k₁) to be diffracted discre th wavelengths (λ₁₁ to λ₁₄) can be supplied, and from which the grating ( 1 ) with these discrete wavelengths λ₁₁ to λ₁₄) is to be illuminated in a certain direction (r₁), and
• - Wherein at each discrete spatial point ( 21 , 22 , 23 or 24 ) each have an exit gate ( 21 ₁, 22 ₁, 23 ₁ or 24 ₁) for removing from the grating ( 1 ) in the specific diffraction order (k₁) to this discrete spatial point ( 21 , 22 , 23 or 24 ) diffracted discrete wavelength (λ₁₁, λ₁₂, λ₁₃ or λ₁₄), which is assigned to this discrete spatial point ( 21 , 22 , 23 or 34 ),

and or

• - Wherein at each discrete spatial point ( 21 , 22 , 23 or 24 ), an entrance gate ( 21 ₁, 22₁, 23₁ or 24₁) is arranged, which the grating ( 1 ) in the determined diffraction order (k₁) to be diffracted discrete wavelength (λ₁₁, λ₁₂, λ₁₃ or λ₁₄), which is assigned to this discrete spatial point ( 21 , 22 , 23 or 24 ), can be supplied, and from which the grating ( 1 ) with this discrete wavelength (λ₁₁, λ₁₂ , λ₁₃ or λ₁₄) is to be illuminated in a particular direction (r₁₁, r₁₂, r₁₃ or r₁₄), and
• - wherein in the a space principal point (10) located an output port (10 ₁) of all for removal of the grid (1) in the be agreed diffraction order (k₁) to this space the main point (10) diffracted discrete wavelengths (λ₁₁, λ₁₂, λl₁₃, λ₁₄) is

marked by

• - Such a diffraction grating ( 1 ) that the grating for further discrete optical wavelengths (λ₂₁ to λ₂₄), which are grouped around a certain further center wavelength (λ₂), in a further diffraction order (k₂) at the further center wavelength (λ2) one from one and the other main room point ( 10 , 20 ) different other main room point ( 30 ) and the other main room point ( 20 ) as well as at each further discrete wavelength (λ₂₁, λ₂₂, λ₂₃ or λ₂₄) the further room main point ( 30 ) and one of these further discrete wavelength (λ₂₁, λ₂₂, λ₂₃ or λ₂₄) individually assigned discrete spatial point ( 21 , 22 , 23 or 24 ) optically maps each other, these discrete spatial points ( 21 to 24 ) are grouped around the other main space point ( 20 ) ,
• - Wherein at the further main point of the room ( 30 ) an entrance gate ( 30 ₁) is arranged, to which the plurality of grating ( 1 ) in the further diffraction order (k₂) to be diffracted further discrete wavelengths (λ₂₁ to λ₂₄) can be fed, and from which the grating ( 1 ) with these further discrete wavelengths (λ₂₁ to λ₂₄) is to be illuminated in a different direction (r₂) from a certain direction (r₁), and
• - Wherein at each of a further discrete wavelength (λ₂₁, λ₂₂, λ₂₃ or λ₂₄) assigned discrete spatial point ( 21 , 22 , 23 or 24 ) an exit gate ( 21 ₁, 22 ₁, 23 ₁ or 24 ₁) for removing the from the grating ( 1 ) in the specific further diffraction order (k₂) to this discrete spatial point ( 21 , 22 , 23 or 24 ) diffracted further discrete wavelength (λ₂₁, λ₂₂, λ₂₃ or λ₂₄) which this discrete spatial point ( 21 , 22nd , 23 or 24 ) is assigned, is arranged,

and or

• - Wherein each of a further discrete wavelength (λ₂₁, λ₂₂, λ₂₃ or λ₂₄) individually assigned discrete spatial point ( 21 , 22 , 23 or 24 ) each have an entrance gate ( 21 ₁, 22 ₁, 23 ₁ or 24 ₁) arranged is, the further discrete wavelength to be diffracted by the grating ( 1 ) in the further diffraction order (k₂) (λ₂₁, λ₂₂, λ₂₃ or λ₂₄), which is assigned to this discrete spatial point ( 21 , 22 , 23 or 23 ) is, and from which the grating ( 1 ) with this further discrete wavelength (λ₂₁, λ₂₂, λ₂₃ or λ₂₄) is to be illuminated in a particular direction (r₁₁, r₁₂, r₁₃ or r₁₄), and
• - wherein an output port (30 ₁) arranged all for removal of the grid (1) in the wide ren diffraction order (k₂) on this other space principal point (30) bent more discrete wavelengths (λ₂₁ to λ₂₄) in the further space principal point (30).

2. Device according to claim 1, characterized in that the grid ( 1 ) is a stigmatically imaging grid. 3. Device according to claim 2, characterized in

• - That the stigmatically imaging grid ( 1 ) is a grid known per se, which is formed on a circle around the main point ( 10 ) ( 1 ₁) with a certain radius (R) and at a point (P) on the circle ( 1 ₁), which strikes from the one main point of the room ( 10 ) in a certain direction (r₁) Lichtbün delachse ( 100 ), has a lattice constant (Λ), which by Λ = λ₀ / n · sin ( γ₁₃) is given, where λ₀ means a wavelength determined by the one and further center wavelength (λ₁, λ₂) and the one and further diffraction order (k₁, k₂), for which λ₀ = k₂ · λ₂-k₁ · λ₁ applies, and n the refractive index of a medium in which the light between the main room points ( 10 , 20 , 30 ) and discrete spatial points ( 11 to 14 ) and the grating ( 1 ) spreads and γ₁₃ the angle between the light beam axis ( 100 ) and one of the other Main room point ( 30 ) in the further direction (r2) outgoing and the point (P) on the circle ( 1 ₁) hitting further light beam axis ( 101 ) mean
• - That the three main spatial points ( 10 , 20 , 30 ) are arranged on a Gera ( 200 ), and
• - That the distance (a₁₂) between the main point ( 10 ) and the other main point ( 20 ) is equal to the radius (R) of the circle multiplied by the number m = k₁ · λ₁ / λ₁ ( 1 ₁) and the distance (a₁₃ ) between one main room point ( 10 ) and the other main room point ( 30 ) is equal to the divided by this number m = k₁ · λ₁ / λ₀ Radi us (R).

4. Device according to claim 3, characterized, that a diffraction order (k₁) equal to the other Beu rules (k₂) is selected. 5. Device according to claim 3 or 4, characterized, that the one center wavelength (λ₁) equal to the other Center wavelength (λ₂) is selected. 6. Device according to one of the preceding claims, characterized by one of the entrance gates ( 30 ₁) of the one and further room main point ( 10 , 30 ) associated optical switching device ( 4 ) which can be switched so that light either to the entrance gate ( 10 ₁) in one main room point ( 10 ) or to another entrance gate ( 30 ₁) in the other main room point ( 30 ). 7. Device according to one of the preceding claims, characterized by one of the output gates ( 10 ₁, 30₁) in one and further main room point ( 10 , 30 ) associated optical switching device ( 4 ) which is switchable so that either only one of the is transmitted output port (10 ₁) or only the reaching of the further output port (30 ₁) to the switching means (4) light from said switching means (4). 8. Device according to one of the preceding claims, characterized by an optical switching device ( 4 ) which is adjustable so that one of the switching device ( 4 ) supplied optical power of the wavelength (λ₀) in each case half to the one and further input gate ( 10 ₁, 30₁) arrives. 9. Device according to one of the preceding claims, characterized by a planar optical waveguide ( 5 ) with a first peripheral edge ( 51 ) on which there are essentially the three main spatial points ( 10 , 20 , 30 ) and the discrete spatial points ( 11 to 14 ) are located, and with one of the one edge ( 51 ) opposite the curved edge ( 52 ) on which the focussing grid ( 1 ) is formed. 10. Device according to one of the preceding claims, characterized in that an entrance and / or exit gate ( 10 ₁, 30 ₁, 21 ₁ to 24 ₁) by an end face of an optical waveguide end section ( 6 ) is defined with a longitudinal axis, which is aligned in the direction (r₁₁, r₂, r₁₁ to r₁₄) in which the light is to be supplied to the grating ( 1 ) or received by the grating ( 1 ). 11. Device according to one of the preceding claims, characterized by a line (λ₁) along which the grating ( 1 ) is formed, conforming optical recording material ( 7 ) for optically recording the grating ( 1 ). 12. The device according to claim 11, characterized by a reversible optical recording material ( 7 ). 13. The device according to claim 12, characterized by a reversi bles recording material ( 7 ) selected from the group of calcogenides. 14. Device according to claim 12, characterized by a material consisting of a photothermoplastic (Ma) ( 7 ). 15. Device according to one of claims 11 to 14, characterized in that a reflective layer ( 8 ) is applied to the side of the recording material ( 7 ) facing away from the side for recording the grid ( 1 ). 16. A method for producing a grid ( 1 ) in a direction according to one of claims 11 to 15, characterized in that the recording material ( 7 ) from one main point of the room ( 10 ) in one direction (r₁) and at the same time from that further main point of space ( 30 ) in the further direction (r₂) with coherent light of a certain record wavelength (λ₀ <is exposed, which interferes with the recording material ( 7 ). 17. The method according to claim 16 for producing a grid ( 1 ) in a device according to claim 3, characterized in that the point (P) on the circle ( 1 ₁) to the circle ( 1 ₁) adhering recording material ( 7 ) is exposed to light of the recording wavelength λ₀ = k₂ · λ₂-k₁ · λ₁. 18. The method according to claim 16 or 17, characterized in that the grating ( 1 ) optionally with a recording wavelength λ₀ on the reversible recording material ( 7 ) is recorded and then deleted with an erasing wavelength. 19. The method according to claim 18, characterized in that after deleting a grid ( 1 ) again a grid ( 1 ) on the reversible recording material ( 7 ) is recorded. 20. A method of operating a device according to one of claims 12 to 15 with a method according to any one of claims 16 to 19, characterized in that with a recording wavelength (λ₀) generates a grating ( 1 ) and then the device in one and further center wavelength (λ₁, λ₂) in the one and further diffraction order (k₁, k₂) is operated as a demultiplexer and / or multiplexer.