DE3843970A1 - Optical wavelength multiplexer and/or demultiplexer - Google Patents

Abstract

Optical wavelength multiplexers (11) and/or demultiplexers have a flat arrangement of optical input and output monomode fibres (22-27), a strip waveguide arrangement (29) to which, on the one end, the optical fibres are coupled, a flat diffraction grating (61) for selectively coupling the optical wavelengths between at least one of the fibres and the other fibres, and an arrangement which has a collimating and/or focusing device (31) and which is coupled to the other end of the strip waveguide arrangement (29). So that in the case of such an optical wavelength multiplexer (11) and/or demultiplexer a simple and low-loss overall construction and simple adjustments can be achieved, it is provided that the collimating and/or focusing device (31) has a concave mirror (51), that the diffraction grating (61) is spatially arranged above or below the inputs or outputs of the strip waveguide arrangement (29) on the end facing away from the fibres, and that the concave mirror (51) covers both these inputs and outputs of the strip waveguide arrangement (29) and the diffraction grating (61). <IMAGE>

Description

The present invention relates to an optical Wavelength multiplexer and / or demultiplexer after the Preamble of claim 1. The present invention relates so both on a multiplexer and on one Demultiplexer as well as an integrated combination a multiplexer and a demultiplexer.

In such a known from DE 34 14 724 A1 optical wavelength multiplexer or demultiplexer the collimating and / or focusing device Lens between the stiffener assembly and a separately indicated diffraction grating is indicated. The Diffraction grating is on the stiff conductor arrangement facing away from the lens. At the Use of single-mode fibers because of their small size Core diameter in relation to their outside diameter only relatively small channel widths in relation to the channel spacing allow the stripline in the stripline arrangement merged to the smallest possible distance. The Construction of this known optical wavelength multiplexer or demultiplexer is due to the lens and the separate Relative arrangement of the diffraction grating behind the lens  complex to build and not low loss.

The object of the present invention is an optical Wavelength multiplexer and / or demultiplexer of the input to create a simple and Low-loss overall structure enables and easy to adjust is.

This task is done with an optical Wavelength multiplexer and / or demultiplexer of the input mentioned type by the features specified in claim 1 solved.

By the measures according to the invention, the one Using concave mirror arrangement, it is possible to use one optical wavelength multiplexer and / or demultiplexer with to create a simple and low-loss overall structure, a simple adjustment is achieved at the same time.

It is appropriate that diffraction gratings either according to the Features of claim 2 or those of claim 4 to provide, variants according to the characteristics of the Claim 3 or those of claim 5 and / or 6 result can.  

Constructively specific embodiments result from the Features of claims 7 to 17. According to the features of Claim 7 it may be appropriate to have a transparent To provide bodies for the concave mirror. It is also possible, according to the features of claim 8, the concave Mirror directly on the substrate, depending on what Use case can be cheaper.

The diffraction grating can also be used in a variety of ways be provided, for example according to the features of claim 9 a transparent plate or according to the characteristics of the Claim 10 directly on the transparent body or on Substrate.

With thin substrates it can U. difficult that the Diffraction grating and the concave mirror transparent body with the substrate on its narrow To connect the front end, for example, with adhesive. Here it is useful if according to the features of claim 15 a connection via made the top of the substrate and an additional mirror is used. This can be according to the features of the claim 16 can be designed as a correction mirror to prevent aberrations of the concave mirror.  

In conventional optical wavelength multiplexers or -Demultiplexers can be used per connection fiber, i.e. per Subscriber line only light of a wavelength with limited Spectral width can be coupled in or out. It must therefore for multiplexing or demultiplexing at several wavelengths external multiplexers per subscriber line or Demultiplexers can be arranged to receive all signals in one fiber summarize or separate again. It is because of that for structural simplification, the features according to claim 17 intended. This makes it sufficient, only in general each have an optical path that is the sum of the optical Record signals of different wavelengths, one to provide such additional multiplexers or demultiplexers. The additional multiplexer or additional demultiplexer is in capable of two or more signals or signal groups to combine different wavelengths, or one only group of signals of different wavelengths separate.

It can also be advantageous according to the characteristics of the Claim 18 this additional multiplexer or Additional demultiplexer in the optical wavelength multiplexer or to integrate demultiplexers. A relatively simple one Embodiment for this arises with the features of Claim 19.

Embodiments of the invention are now based on the Drawing described and explained in more detail. It shows

Fig. 1 shows a schematic plan view of an optical wavelength division multiplexer according to a first embodiment of the present invention,

Fig. 2A, B and C a schematic illustration of an optical wavelength division multiplexer in a top view, side view and end view, the present invention according to a second embodiment,

Fig. 3 present a schematic side view of an optical wavelength division multiplexer according to a third embodiment of the invention,

FIGS. 4A and B in a schematic plan view and a side view of an optical wavelength division multiplexer according to a fourth embodiment of the present invention,

Fig. 5A and B in a schematic plan view and a side view of an optical wavelength division multiplexer according to a fifth embodiment of the present invention,

Fig. 6 shows a schematic representation of an optical wavelength (de) multiplexer for bidirectional operation according to a sixth embodiment of the present invention,

Fig. 7 shows a schematic representation of an optical wavelength (de) multiplexer for bidirectional operation according to a seventh embodiment of the present invention,

Fig. 8 shows a schematic representation of an optical wavelength (de) multiplexer for bidirectional operation according to an eighth embodiment of the present invention, and

Fig. 9 present a schematic plan view of an optical wavelength (de) multiplexer for bidirectional operation according to a ninth embodiment of the invention.

Although only optical wavelength multiplexers according to several exemplary embodiments of the present invention are described below with reference to FIGS. 1 to 5, it goes without saying that corresponding optical wavelength demultiplexers can also be constructed in such a way that only inputs and reverse or interchange outputs of the optical fibers used. Furthermore, it is also possible to construct combined devices in the form of optical wavelength multiplexer-demultiplexers in the manner according to the invention, as is shown, for example, using the exemplary embodiment of FIGS. 6 to 9.

Referring to FIG. 1, the optical wavelength multiplexer 11 in a planar array 21 of a plurality of input monomode fibers, of which four fibers are illustrated here 22-26, and an output monomode fiber optically coupled 27th The input fibers 22-26 of the arrangement (of the fiber array) 21 transmit optical signals with a wavelength of λ ₁ , λ ₂ , g ₃ , λ ₄ or λ _N , while the output single-mode fiber 27 optical signals of all wavelengths, that is, g ₁ to λ _N transmits. The optical summation of the wavelengths g ₁ , λ ₂ , λ ₃ , λ ₄ and λ _N transmitted via the individual input fibers 22-26 takes place with the aid of the optical wavelength multiplexer 11 .

The wavelength multiplexer 11 has a strip line arrangement or array 29 which is connected at one end to the fiber arrangement 21 and a collimating and / or focusing device 31 which is connected to the other end of the strip line arrangement 29 optically connected.

The stripline arrangement 29 is of a conventional type, ie it has a substrate 41 on or in which waveguides 42 are arranged. The number of waveguides 42 corresponds to the number of single- mode fibers 22-27 that are to be coupled to the stripline arrangement 29 . For an increased packing density of the optical transmission paths in the device 31 for the individual wavelengths, the waveguides 42 are arranged in such a way that they converge towards one another from the end of the substrate 41 coupled with the monomode fibers 22-27 , so that their distance from one another is substantially reduced is. In the exemplary embodiment, the waveguides 42 are arranged on the substrate 41 in an upper or lateral region 43 .

Arranged on the end face 46 of the substrate 41 , in which the waveguides 42 open, is a transparent body 47 , the collimating / focusing device 31 , the edge face 48 of which faces away from the end face 46 of the substrate 41 is concave and provided or covered with a mirror 51 is. The concave mirror 51 , which is curved on one side, is formed in that the edge surface 48 is provided with a reflective coating. However, it is also possible to integrate the concave mirror 51 into the transparent body 47 .

A flat diffraction grating 61 is provided immediately below (according to FIG. 1) or laterally next to the mouth of the waveguide 42 in a lateral region 43 of the end face 46 . In the exemplary embodiment shown, the diffraction grating 61 is applied in the other lateral region 44 of the substrate 41 in the end face 46 thereof, for example by scratching or pressing. It goes without saying that it is also possible to introduce the diffraction grating 61 in this area into the opposite end face of the transparent body 47 . It is also possible to attach an additional plate provided with the diffraction grating 61 in this area between the transparent body 47 and the substrate 41 .

As can be seen from FIG. 1, the wavelengths λ ₁ to λ _{N are brought} from the input fibers 22-26 opening at different angles into the end face 46 of the substrate 41 onto the concave mirror 51 and from there are transformed by reflection into parallel light beams which impinge on the diffraction grating 61 at a uniform angle q . From there, the light beams with the individual wavelengths λ ₁ to g _{N are} thrown at a uniform angle β of greater than γ onto an upper region of the concave mirror 49 which directs the light beams with the different wavelengths onto the mouth of the output single-mode fiber 27 in the substrate 41 collimated or focused.

Fig. 2 shows (the fiber arrangement is not shown) an optical wavelength multiplexer 12 , in which a stripline arrangement 29 _{2 is} used, which differs from the stripline arrangement of Fig. 1 only in that the waveguide 42 _{2 end} within the substrate 41 ₂ and that an additional mirror 71 is provided at the end of the waveguide 42 ₂ in the substrate 41 ₂ , which deflects the light beams with the wavelengths λ ₁ to λ _N essentially by 90 ° upwards. For this reason, a collimating or focussing device 32 is placed on the surface 72 of the substrate 41 ₂ in this exit region of the light rays and has a double-curved concave mirror 52 on its opposite edge surface. In this exemplary embodiment, the flat diffraction grating 62 is arranged on a surface 73 of the transparent body 47 ₂ , which runs at an acute angle to the perpendicular to the surface 72 of the substrate 41 ₂ and which is arranged in a lateral region above the substrate 41 ₂ . The paths of the light beams of the individual wavelengths λ ₁ to λ _N and their focusing and reflection in the form of a uniform light beam to the single output fiber corresponds to the optical process shown and described with reference to FIG. 1.

FIG. 3 shows an optical wavelength multiplexer 13 , which is constructed similarly to the multiplexer 12 of FIG. 2, to the extent that the transparent body 47 _{3 is placed} on a substrate 41 _{3 of} the strip line arrangement 29 ₃ , the waveguide of which 42 ₃ stop facing the front surface of the substrate 41. ₃ In this exemplary embodiment, however, the concave mirror 53 is provided both on the transparent body 47 ₃ and on the concave end surface of the substrate 41 ₃ which is flush therewith. The flat diffraction grating 63 is provided on a surface 74 of the transparent body 47 ₃ , which is provided directly above the surface 72 of the substrate 41 ₃ and at an obtuse angle to it.

Thus, the light beams with the different wavelengths g ₁ to λ _{N are} further thrown onto the concave mirror 53 after emerging from the waveguides 42 ₃ and from there are reflected onto the diffraction grating 63 , from where the parallel light beams are reflected back onto the mirror 53 and from there, focusing on the mouth of the output fiber (not shown here). In this exemplary embodiment, in which an additional mirror is missing, substrate 41 ₃ and transparent body 47 ₃ are glued to one another.

FIG. 4 shows an optical wavelength multiplexer 14 in which the concave mirror 54 and the plane diffraction grating 64 are integrated in the substrate 41 _{4 of} the strip line arrangement 29 _{4 in order} to avoid glue spots, ie in this exemplary embodiment substrate 41 ₄ and transparent body 47 ₄ as a device 34 in one piece.

As is apparent from the Fig. 4, the diffraction grating is provided on a side surface 75 of the substrate 41 ₄ 64 while the concave mirror 54 is provided at the Endstirn of the substrate 41 _4. The optical diffraction and reflection conditions and the routing of the signals with the wavelengths g ₁ , λ ₂ , λ ₃ , λ ₄ and λ _N in the waveguides 42 ₄ result directly from the drawing or the aforementioned statements regarding the previous exemplary embodiments.

The optical wavelength multiplexer 15 shown in FIG. 5 is again in two parts, the substrate 41 _{5 of} the stripline arrangement 29 ₅ and the transparent body 47 _{5 of} the device 35 being formed and joined to one another such that essentially one with the multiplexer 14 of FIG. 4 gives comparable multiplexer 15 . The only difference is that the curvature of the concave mirror 55 is such that the light rays are not reflected at an acute angle as in FIG. 4, but, as can be seen from FIG. 5, at an obtuse angle, so that the plane diffraction grating 65 is arranged directly above the reflection region of the concave mirror 55 .

It is understood that in all of these exemplary embodiments of FIGS . 2 to 5 the stripline arrangement 29 ₂ , 29 ₃ , 29 ₄ , 29 ₅ is coupled to a corresponding flat single-mode fiber arrangement 21 ( FIG. 1).

The further FIGS. 6 to 9 each show a bidirectional optical wavelength multiplexer demultiplexer 16, 17, 18 and 19 , which is designed to couple or decouple multiple signals of different wavelengths in the multiplex or in the demultiplex per connection monomode fiber . In all the exemplary embodiments shown below, the single-mode fiber arrangement 21 and stripline arrangement 29 shown in FIG. 1 are omitted for the sake of clarity. It is understood that these are to be used in a corresponding manner.

FIG. 6 shows the collimating / focusing device 36 in the form of a transparent body 47 ₆ , which corresponds approximately to that of the multiplexer 11 according to FIG. 1, it being shown that the planar diffraction grating 66 is incorporated into the corresponding end face of the transparent body 47 ₆ . Another difference is that the curvature of the concave mirror 56 is such that the angle between the incident light rays is greater than the angle β of the respective collimated light rays.

According to this exemplary embodiment, connecting fibers 91, 92 etc., which lead to the individual subscribers, for example a telephone system, carry incoming signals with the wavelength λ ₁ , λ ₂ . . . or λ _N and returning signals with the wavelength g _{N + 1} ,. . . or λ _M. In order to achieve such a separation of the signals of different wavelengths or a combination of the signals with different wavelengths on a transmission fiber 97 , an additional multiplexer or additional demultiplexer 81 is provided therein, which is divided into two adjacent wavelength ranges or one Merging the two neighboring wavelength ranges λ ₁ . . . λ _N and g _{N + 1} . . . λ _M carries out. In this exemplary embodiment, optical signals returning and returning are separated or combined from one another by means of an additional demultiplexer or additional multiplexer 81 . A division takes place in the collimating / focusing device 36 in such a way that each subscriber fiber has two wavelengths λ ₁ located at a distance from one another. . . λ _{N + 1} or λ _N. . . g _{M are} assigned, or a combination of these signals running back and forth in the individual subscriber fibers. It is essential that λ ₁ . . . g _{N is} less than λ _{N + 1} . . . λ _M and that β a (N + 1) is chosen. This ensures that each participant is assigned two wavelengths with a relatively large distance.

FIG. 7 shows an exemplary embodiment of a bidirectional optical wavelength multiplexer demultiplexer 17 , with which it is possible to assign two optical signals of adjacent wavelengths to each subscriber connecting fiber 91, 92 etc. For this purpose, a λ- selective single-mode coupler 82 is arranged in the transmission fiber 97 , in which the total group of the returning and returning signals with the wavelengths λ ₁ to λ _{N is divided} into two signal groups with the wavelengths λ ₂ , λ ₄ , λ ₆ . . . or g ₁ , λ ₃ , λ ₆ ,. . . be separated. The collimating / focussing device 37 is designed in accordance with the device 36 of FIG. 6, while the flat diffraction grating 67 is provided in a transparent plate 45 to which the stripline arrangement is connected.

Fig. 8 shows a bidirectional optical wavelength multiplexer-demultiplexer 18, by which it is possible to have more than two to transfer 92 or bidirectionally namely here three signals of respectively different wavelengths per subscriber line single-mode fiber 91. For this purpose, an additional demultiplexer or additional multiplexer 83 is provided, which is capable of dividing the total group of the returning and returning signals of the wavelengths λ ₁ to λ _N into three signal groups with wavelengths of λ ₁ , λ ₄ , g ₇ , . . . or λ ₂ , λ ₅ , λ ₆ ,. . . or λ ₃ , λ ₆ , λ ₉ ,. . . separate or combine these signal groups. The collimating / focusing device 38 and the arrangement of the flat diffraction grating 68 correspond to those of FIG. 7.

FIG. 9 shows a bidirectional optical wavelength multiplexer demultiplexer 19 , in which the additional multiplexer or additional demultiplexer is integrated in the collimating / focusing device 39 . For this purpose, the transparent body 47 is divided into two, the main part 49 having the plane diffraction grating 69 on the input side with an acute-angled arrangement, which is arranged in this exemplary embodiment between the input of the transmission fiber 97 and the input of the other subscriber line monomode fibers 91, 92 etc. The transparent main body part 49 has an end face 86 concave on one side opposite the input side, which is designed as a mirror surface 87 in an upper region and as a filter 88 in a lower region. While the concave additional mirror surface 87 is designed as a completely reflecting surface, the filter surface 88 is designed such that it transmits a specific wavelength range and completely reflects another specific wavelength range. The wavelength range transmitted by this filter surface 88 is reflected by a concave mirror surface 59 which is arranged at a distance from it and which is provided at the end on a transparent additional body part 50 .

If, for example, the individual transmission fiber carries signals with the wavelengths λ ₁ to λ _N in one direction and λ _{N + 1} to g _M in the other direction, the one wavelength group is passed through by the filter 88 , while the other wavelength group is reflected. The two wavelength groups reflecting from the filter 88 and the mirror 59 are reflected at a difference angle β onto the diffraction grating 69 and from there are spatially separated onto the additional mirror 87 , from where a respective pair of wavelengths is reflected onto a single-mode fiber 91, 92 etc. . The same applies to the effect as a multiplexer in the opposite direction.

It goes without saying that this exemplary embodiment according to FIG. 9 can also be modified or expanded in such a way that more than two wavelength ranges can be separated from one another. This can be done in such a way that, instead of the additional mirror 87, a further filter 88 is provided, which passes a certain wavelength range, which is then reflected on the mirror 59 , and reflects another specific wavelength range, etc.

Claims (19)

1. Optical wavelength multiplexer and / or demultiplexer, with a planar arrangement of optical input and output fibers, preferably single-mode fibers, with a planar stripline arrangement, to which the optical fibers are coupled at one end, with a planar diffraction grating for selectively coupling the optical wavelengths between at least one of the fibers and the other fibers and an arrangement comprising a collimating and / or focusing device which is coupled to the other end of the stripline arrangement, characterized in that the collimating and / or focusing device ( 31-39 ) has a concave mirror ( 51-59 ), that the diffraction grating ( 61-69 ) is arranged spatially above or below the inputs and outputs of the stripline arrangement ( 29 ) at its end facing away from the fibers, and that the concave mirror ( 51- 59 ) both these inputs and outputs of the stripline arrangement ( 29 ) and the loading Eye grille ( 61-69 ) covered. 2. Multiplexer and / or demultiplexer according to claim 1, characterized in that the diffraction grating ( 61 ) in the plane of the strip line arrangement ( 29 ) and its inputs and outputs are arranged adjacent. 3. Multiplexer and / or demultiplexer according to claim 2, characterized in that the inlet and outlet axes of the inputs and outputs of the stripline arrangement ( 29 ) with an imaginary to the diffraction grating ( 61 ) includes an acute angle. 4. Multiplexer and / or demultiplexer according to claim 1, characterized in that the diffraction grating ( 62, 63 ) is provided in a plane which is arranged at an acute angle to the perpendicular to the plane of the strip line arrangement ( 29 ). 5. Multiplexer and / or Demulitplexer according to claim 1, characterized in that the diffraction grating ( 63 ) is arranged directly above the stripline arrangement. 6. Multiplexer and / or demultiplexer according to claim 4, characterized in that the diffraction grating ( 63 ) is arranged on a side edge region of the stripline arrangement. 7. Multiplexer and / or demultiplexer, in which the stripline arrangement has a substrate which is provided with adjacent waveguides, according to at least one of claims 1 to 6, characterized in that on the surface area of the substrate ( 41 ) on which the relevant inputs and outputs of the waveguides ( 42 ) are provided, a transparent body ( 47 ) adjoins the concave mirror ( 51-53, 55-59 ) at least partially on its opposite surface. 8. Multiplexer and / or demultiplexer, in which the stripline arrangement has a substrate which is provided with adjacent waveguides, according to at least one of claims 1 to 6, characterized in that the substrate ( 41 ) itself with a concave mirror ( 54 ) and a diffraction grating ( 64 ) is provided. 9. Optical wavelength multiplexer and / or demultiplexer according to claim 7, characterized in that between the transparent body ( 47 ) and the substrate ( 41 ) is provided with a diffraction grating ( 67, 68 ) provided transparent plate ( 45 ). 10. Multiplexer and / or demultiplexer according to claim 7 or 8, characterized in that the diffraction grating ( 61-66, 69 ) is applied directly to a corresponding surface area of transparent bodies ( 47 ) or substrate ( 41 ). 11. Multiplexer and / or demultiplexer according to claim 9 or 10, characterized in that the diffraction grating ( 61-69 ) is applied to the surface area in question by scratching, pressing, or the like. 12. A multiplexer and / or demultiplexer according to claim 7, characterized in that the concave mirror ( 53 ) is provided in mutually flush surface areas of the transparent body ( 47 ) and substrate ( 41 ). 13. Multiplexer and / or demultiplexer according to claim 7 or 8 or 12, characterized in that the respective one-sided curved surface area of the transparent body ( 47 ) and / or substrate ( 41 ) is provided with a reflective coating. 14. Multiplexer and / or demultiplexer according to at least one of claims 7 or 9 to 12, characterized in that the transparent body ( 47 ) is provided with a film waveguide ( 42 ). 15. Multiplexer and / or demultiplexer according to claim 7, characterized in that the transparent body ( 47 ) on an upper side of the substrate ( 41 ) in the region of the relevant inputs and outputs of the waveguide ( 42 ) is attached and that between the transparent body ( 47 ) and substrate ( 41 ), preferably an additional mirror ( 71 ) is provided within the substrate. 16. A multiplexer and / or demultiplexer according to claim 15, characterized in that the additional mirror ( 71 ) is designed as a correction mirror. 17. Multiplexer and / or demultiplexer according to at least one of the preceding claims, characterized in that in the at least one optical path, which takes up the sum of the optical signals of different wavelengths, an additional multiplexer ( 81 ) and / or additional demultiplexer ( 81 ) is arranged for spatially combining at least two signals of different wavelengths or groups of signals of different wavelengths or for spatially separating the entirety of signals of different wavelengths. 18. A multiplexer and / or demultiplexer according to claim 17, characterized in that the additional multiplexer and / or additional demultiplexer ( 81 ) in the diffraction grating ( 69 ) and the focusing and / or collimating device ( 39 ) having an arrangement ( 21 ) is integrated. 19. Multiplexer and / or demultiplexer according to claim 18, characterized in that a diffraction grating ( 69 ) and the concave mirror ( 59 ) having, preferably multi-piece transparent body ( 47 ) on a surface area at least one filter ( 88 ) which determines a particular one Transmits wavelength range and reflects another specific wavelength range, and has a further mirror ( 87 ) on another surface area.