DE102013225611B4 - Optical receiver for optical wireless communication - Google Patents

Abstract

An optical receiver (1) for optical wireless communication, comprising a refracting means (2) for refracting an incident light signal (LE) so as to divide the incident light signal (LE) into partial light signals (LT); a first converter device (3), which comprises a plurality of first converter elements (9) for coupling one of the partial light signals (LT) in each case an optical signal line (10) so as to produce a coupled optical signal (LK) per optical signal line (10) ; a switch device (4) which has a singular or a plurality of switches (15), which are each arranged in one of the optical signal lines (10) and designed to pass on the coupled-in light signal (LK) in a first switch position and in a second switch position Block switch position, so as to generate at least one coupled switchable light signal (LS); and a detector device (5) having a singular or a plurality of detector elements (14) for generating an electrical signal (ES) as a function of at least one of the coupled switchable light signals (LS).

Description

The present invention relates to an optical receiver for optical wireless communication.

Optical transceivers comprising an optical transmitter and an optical receiver are widely used today for optical wireless communication. The requirements for range and coverage with a simultaneously decreasing form factor increase steadily.

The requirements for a transceiver for optical wireless communication consist in a high data rate, in an application-specific radiation characteristic, in an application-specific field of view, resulting in a long range and in a large detection range, in a simple handling by the user, in a small form factor , in a high sensitivity, in a wide dynamic range of the receiver and in a transmitting element, which meets the eye safety requirements.

Today's transceivers for optical wireless communication consist of a lens and a photodetector. The optical characteristics, such as sensitivity, field of view and dynamic range, of this arrangement are determined by the size of the lens, the size of the photodetector and the electrical properties of the detector, such as electrical bandwidth, input capacitance, carrier mobility and sensitivity. Since a high data rate requires a very small input capacitance of the detector, which for proportionality reasons results in a very small diode area, the performance of the system with respect to the field of view is severely limited. A conditional compensation of this disadvantage can be achieved by complex and large optics. As a result, however, the recipient becomes too large and too heavy as well as not cost-relevant for the market.

With a small form factor, conventional means can not realize a large field of view with a high data rate at the same time. Application-specific requirements can often not be met.

From the US 6,983,110 B2 For example, an optical receiver having an input path, a matrix light sensor, a converging optical lens and an information signal generator is known. The positive lens is associated with the optical input path. The matrix light sensor includes light detectors and a photosensitive surface. Each light detector generates a light-dependent electrical signal which is supplied to the information signal generator.

The object of the present invention is to provide an improved optical receiver.

The object is achieved by an optical receiver for optical wireless communication, with
a refracting means for refracting an incident light signal so as to divide the incident light signal into partial light signals;
a first converter device which comprises a plurality of first converter elements for coupling one of the partial light signals into an optical signal line in each case so as to generate a coupled-in optical signal per optical signal line;
a switch device having a singular or a plurality of switches which are each arranged in one of the optical signal lines and adapted to forward the coupled light signal in a first switch position and to block in a second switch position, so as to at least one coupled switchable light signal produce; and
a detector device with a singular or a plurality of detector elements for generating an electrical signal as a function of at least one of the coupled switchable light signals.

The light refraction device is used to break the incident light so that each of the converter elements, a portion of the incident light, ie a partial light signal, is supplied.

By means of the light refraction device, it is possible to set the desired field of view targeted. In this case, the field of view may be divided into partial fields of view, which are each imaged by one of the generated partial light signals. The partial view fields can be provided overlapping or non-overlapping.

By now each of the partial light signals is coupled by means of the converter device in a separate optical signal line, each of the partial light signals can be forwarded and processed independently of the other partial light signals as a coupled light signal.

By now individual or preferably all optical signal lines associated with switches, which make it possible to forward the coupled light signals in a first switch position and to block in a second switch position, the total power of the coupled switchable light signals can be influenced. In this way, a great sensitivity of the Receiver can be realized without the risk of overriding the receiver. If, for example, the incident light signal has a low power, then all switches can be brought into the first switching position in order to obtain the greatest possible overall power of the coupled switchable light signals. In contrast, if the incident light signal has a very high power, some of the switches can be brought into the second switching position, so as to reduce the overall power of the coupled switchable light signals, so that an override of the receiver is avoided. In addition, it is possible to selectively hide interference signals. Interference signals can be recognized, for example, by the nature of their modulation. The switches can be switched automatically by an electronic control device based on the characteristics of the incident light signals.

The switches can be designed, for example, as electro-optical switches. The electro-optical switches can be based on organic or on inorganic materials. Possible are liquid crystal mixtures, for. As a mixture of the liquid crystal E44 and polymethyl methacrylate, so-called Dye-Doped Polymer-Stabilized Blue Phase Liquid Crystals (DDPSBP-LC) or silicon-based microring resonators in combination with PIN diodes (English: positive intrinsic negative diode).

With the aid of the detector device, the coupled switchable light signals can be converted into electrical signals and then further processed analogously and / or digitally. The detector elements may for example consist of indium gallium arsenide (InGaAs) of gallium arsenide (GaAs), silicon (Si) or germanium (Ge). In particular, photodiodes, such as PIN photodiodes, may be used.

The invention enables a small form factor with simultaneous application-specific field of view. It is even possible to have an all-round view field so that even an omnidirectional receiver becomes possible. As a result, an optical wireless transmission path can be realized whose range is independent of the relative orientation of transmitter and receiver. In addition, the dynamic range of the receiver can be increased so that data transmission with the same receiver can be easily ensured for very short to medium ranges. Ie. the receiver is not overdriven with a short range (high optical reception power) and with sufficiently long range (very small reception power) a sufficiently high sensitivity is provided. Since the detector device can contain a plurality of detector elements, they can be designed to have a small area, so that they can have a small input capacitance, so that the receiver can be operated at high data rates.

According to an advantageous embodiment of the invention, the light refraction device comprises at least one lens array with a plurality of lenses for breaking the received light signal. A lens array is understood to be a structural unit having a multiplicity of lenses. The lens array may comprise individually mounted lenses or a coherent lens composite. For example, plano-convex lenses, biconvex lenses, aspheric lenses, Fresnel lenses, CPC lenses, or DTIRC lenses may be used. The lenses may include, for example, glass, plastic, polymers, silicon, germanium, etc. The production of the lenses can be carried out in a pressing process, in an injection molding process, in an imprint process, in a semiconductor process, etc. A single lens may in one embodiment direct the light received by it to exactly one converter element. In this case, the lens produces exactly one of the partial light signals. In another embodiment, a single lens may direct the light received by it to a plurality of converter elements. In this case, the single lens generates several partial light signals. In another embodiment, a plurality of the lenses direct the respective light received by them on a lens. In this case, several lenses together produce a partial light signal. As an alternative to the lens array, an optical grating or a diffuser can be used.

According to an advantageous development of the invention, at least two lens arrays are provided, which divide incident light signals from different directions into partial light signals. In this way, the field of view can be increased in a simple manner, wherein the sensitivity of the receiver in different partial fields of view can be almost constant. For example, a plurality of converter arrays may each be combined with a lens array arranged on different sides of a receiving module, so as to provide a very large field of view. Ideally, such an optical omnidirectional antenna can be realized.

According to an advantageous development of the invention, the first converter device comprises at least one converter array with at least a part of the first converter elements. In this case, a converter array is understood to be a structural unit which comprises a large number of converter elements. Each converter element can couple a partial light signal, which originates from one lens or from several lenses, into an optical fiber. The converter elements of a converter array can be on flat or curved surfaces be arranged. In particular, circular arrangements or rectangular arrangements of the converter elements are possible.

According to an advantageous development of the invention, the first converter elements are designed as grating couplers. The grating couplers can optionally be provided with a so-called taper. As a result, a direct fiber fixation is effected at a defined distance from a coupling region of the grating coupler. The grating coupler may be made of silicon, of germanium, of glass, or of a polymer in a pressing process, in an etching process, in an imprint process or in a semiconductor process.

According to an advantageous development of the invention, at least one of the lens arrays is arranged on one of the converter arrays. In this case, the lens array and the converter array form a structural unit. As a result, a precise alignment of the lens array with respect to the converter array can be effected. In this case, each converter element can be assigned exactly one lens. But it is also possible that each converter element is associated with a plurality of lenses. Finally, it is also possible that several converter elements share a lens.

According to an advantageous development of the invention, a phase compensation arrangement for compensating phase differences of the light signals coupled in different optical signal lines is provided between the converter device and the detector device. Especially with larger lens arrays or when using multiple lens arrays, a phase compensation of the individual optical signal lines may be useful to prevent mutual weakening or extinction of the coupled light signals in the further processing of the coupled light signals. A phase compensation is understood here to mean a measure which equates the phases of the different partial light signals relative to one another.

According to an advantageous development of the invention, the phase compensation arrangement comprises at least one static delay element which is assigned to one of the optical signal lines. A static delay element, ie a delay element which constantly causes a defined delay of the respective coupled-in light signals, represents a simple possibility for matching the phases of different coupled-in light signals to one another. In the simplest case, the static delay element is realized by an extension of the optical signal line. However, microring resonators are also possible as static delay elements.

According to an advantageous development of the invention, the phase compensation arrangement comprises at least one dynamically connectable delay element which is assigned to one of the optical signal lines. By using dynamically switchable delay elements, the accuracy of phase matching can be improved. In particular, the phase matching can thus be carried out as a function of an actual phase difference. The dynamic delay elements can be controlled automatically by an electronic control device.

According to an advantageous development of the invention, a wavelength-sensitive filter device is arranged between the converter device and the detector device and has at least one filter element for filtering at least one of the light signals coupled into one of the optical signal lines. By means of such a filter device, it is possible to remove interfering extraneous signals from the injected light signals. In this case, individual or all of the coupled-in light signals can be filtered. The filter elements can be switched on and off statically or dynamically. The passband of the filter elements may be in the range of 850 nm, 940 nm, 980 nm, 1330 nm, or 1550 nm, for example. But there are other areas possible. Micro-ring resonators, for example so-called grating-assisted microring resonators, or electrooptically selective materials can be used as filter elements.

According to an advantageous embodiment of the invention, a second converter device is provided, which comprises a singular or a plurality of second converter elements for coupling the switched light signal from at least one of the optical signal lines, wherein the converter elements are formed so that from coupled light signal perpendicular to the detector elements meets. The second converter elements may be formed as the first converter elements, although the input and the output are reversed.

According to an advantageous development of the invention, the coupled-out light signals from at least two of the optical signal lines can be fed to one of the detector elements. As a result, the optical signal power can be increased at one of the detector elements, so that a greater sensitivity can be achieved.

According to an advantageous embodiment of the invention, the first converter elements of the first converter arrays and the the first converter array associated switch and / or the first converter array associated detector elements formed on one or more levels of a substrate.

According to an advantageous development of the invention, the delay elements assigned to the first converter array are formed on the substrate.

According to an advantageous development of the invention, the filter elements associated with the first converter array are formed on the substrate.

According to an advantageous development of the invention, the second converter elements assigned to the first converter array are formed on the substrate.

By forming a plurality of the elements on one or more levels of the common substrate, the receiver can be manufactured easily and precisely.

The above-explained and / or reproduced in the dependent claims advantageous embodiments and refinements of the invention can, in addition to z. B. in cases of clear dependencies or incompatible alternatives, individually or in any combination with each other.

The invention and its advantageous embodiments and further developments and advantages thereof are explained in more detail below with reference to drawings.

They show, in each case in a schematic outline sketch:

1 a block diagram of an embodiment of a receiver according to the invention;

2 a block diagram of a lens array and a converter array of an embodiment of a receiver according to the invention;

3 a spatial representation of a lens array and a converter array of an embodiment of a receiver according to the invention;

4 a spatial representation of a converter element of an embodiment of a receiver according to the invention;

5 a block diagram of a light refracting device, a converter device and a switch device of an embodiment of a receiver according to the invention;

6 a block diagram of an embodiment of a receiver according to the invention;

7 a block diagram of an embodiment of a receiver according to the invention;

8th a block diagram of an embodiment of a receiver according to the invention;

9 a block diagram of an embodiment of a receiver according to the invention; and

10 a spatial representation of a converter array, a phase compensation arrangement, a switch device and a detector device of an embodiment of a receiver according to the invention.

1 shows a block diagram of an embodiment of a receiver according to the invention 1 for optical wireless communication, with
a light-breaking device 2 for breaking an incident light signal LE so as to split the incident light signal LT into n partial light signals LT1 to LTn;
a first converter device 3 comprising a plurality of first converter elements for coupling one of the partial light signals LT1 to LTn in each case an optical signal line so as to produce a coupled optical signal LK1 to LKn per optical signal line;
a switch device 4 which has a singular or a plurality of switches which are each arranged in one of the optical signal lines and adapted to forward the coupled light signal LK1 to LKn in a first switching position and to block in a second switch position, so at least one coupled switchable light signal Generate LS1 to LSn; and
a detector device 5 with a singular or a plurality of detector elements for generating an electrical signal ES1 to ESm in dependence on at least one of the coupled switchable light signals LS1 to LSn.

By means of the light refraction device 2 It is possible to set the desired field of view targeted. In this case, the field of vision can be divided into partial fields of view, which are each imaged by one of the generated partial light signals LT1 to LTn. The partial view fields can be provided overlapping or non-overlapping.

By now each of the partial light signals LT1 to LTn by means of the converter device 3 is coupled into its own optical signal line, each of the partial light signals LT1 to LTn independently of the other partial light signals LT1 to LTn forwarded as a coupled light signal LK1 to LKn and are processed. The number n of the partial light signals corresponds to the number n of the optical signal lines and thus the number n of the coupled-in light signals LK1 to LKn.

By now individual or preferably all optical signal lines associated with switches, which make it possible to forward the coupled light signal LK1 to LKn in a first switch position and to block in a second switch position, the total power of the coupled switchable light signals LK1 to LKn can be influenced. In this way, a great sensitivity of the receiver 1 without the risk of overriding the receiver 1 will be realized. If, for example, the incident light signal LE has a low power, then all the switches can be brought into the first switching position in order to obtain the greatest possible overall power of the coupled switchable light signals LS1 to LSn. In contrast, if the incident light signal LE has a very high power, some of the switches can be brought into the second switching position, so as to reduce the total power of the coupled switchable light signals LS1 to LSn, so that an override of the receiver 1 is avoided. In addition, it is possible to selectively hide interference signals. Interference signals can be recognized, for example, by the nature of their modulation. The switches can be automatically switched by an electronic control device based on the properties of the incident light signals or LE.

With the help of the detector device 5 For example, the coupled switchable light signals LS1 to LSn can be converted into electrical signals ES1 to ESm and then further processed analogously and / or digitally. It can be provided that each of the coupled switchable light signals LS1 to LSn is fed to exactly one detector element and converted into an individual electrical signal ES1 to ESm. In this case, the number n of the coupled switchable light signals LS1 to LSn corresponds to the number m of the electrical signals ES1 to ESm. However, it is also possible to guide a group of light signals LS1 to LSn together to one of the detector elements. Then, the number n of the coupled-in light signals LS1 to LSn is greater than the number m of the electrical signals ES1 to ESm. The detector elements may be in a detector array 19 be arranged, wherein under a detector array 19 a structural unit with a plurality of detector elements is understood.

The invention enables a small form factor with simultaneous application-specific field of view. It is even possible to have an all-round view field, so that even an omnidirectional receiver 1 becomes possible. As a result, an optical wireless transmission path can be realized whose range is independent of the relative orientation of transmitter and receiver 1 is. In addition, so can the dynamic range of the receiver 1 be enlarged, thereby transmitting data with the same receiver 1 can be easily ensured at very short to medium ranges. Ie. the recipient 1 is not overdriven with a short range (high optical reception power) and with a long range (very low reception power) a sufficiently high sensitivity is provided. Since the detector device 5 several detector elements 14 can contain, they can be designed small area, so that they can have a small input capacitance, so that the receiver 1 can be operated at high data rates.

According to an advantageous development of the invention, the light-breaking device comprises 2 at least one lens array 6 with a plurality of lenses for breaking the received light signal LE. Under a lens array 6 In this case, an assembly with a plurality of lenses is understood. The lens array 6 may include individually mounted lenses or a contiguous lens composite. For example, plano-convex lenses, biconvex lenses, aspheric lenses, Fresnel lenses, CPC lenses, or DTIRC lenses may be used. The lenses may include, for example, glass, plastic, polymers, silicon, germanium, etc. The production of the lenses can be carried out in a pressing process, in an injection molding process, in an imprint process, in a semiconductor process, etc. A single lens can focus the light onto one or more converter elements. As an alternative to the lens array, an optical grating or a diffuser can be used.

According to an advantageous development of the invention, the first converter device comprises 3 at least one converter array 8th with at least a part of the first converter elements. Under a converter array 8th In this case, a structural unit is understood which comprises a multiplicity of converter elements. Each converter element can couple a partial light signal, which originates from one lens or from several lenses, into an optical fiber. The converter elements of a converter array 8th can be arranged on plan or curved surfaces. In particular, circular arrangements or rectangular arrangements of the converter elements are possible.

2 shows a block diagram of a lens array 6 and a converter array 8th an embodiment of a receiver according to the invention. The configuration of 2 can be provided in each of the embodiments of the inventive receiver described here be. In 2 includes the light refraction device 2 by way of example a lens array 6 which j lenses 7.1 to 7.J having. In the embodiment of 2 corresponds to the number j of the lenses 7.1 to 7.J the number n of the first converter elements and thus the number n of the coupled-in light signals LK1 to LKn. In other embodiments, however, j can also be greater or smaller than n.

According to an advantageous development of the invention, at least one of the lens arrays is 6 on one of the converter arrays 8th arranged. In this case form the lens array 6 and the converter array 8th a structural unit. This allows a precise alignment of the lens array 6 with respect to the converter array 8th be effected. In this case, each converter element exactly one lens 7.1 to 7.J be assigned. But it is also possible that each converter element multiple lenses 7.1 to 7.J assigned. Finally, it is also possible for several converter elements to be a lens 7.1 to 7.J share.

3 shows a spatial representation of a lens array 6 and a converter array 8th an embodiment of a receiver according to the invention 1 , Incident light LE falls on one as a lens array 6 trained light refraction device 2 , In this way, broken light LT arises which as the converter arrays 8th trained first converter device 3 falls.

4 shows a spatial representation of a converter element 9 an embodiment of a receiver according to the invention 1 ,

According to an advantageous development of the invention, the first converter elements 9 as a grating coupler 9 educated. The grating coupler 9 can be optionally equipped with a so-called Taper. As a result, a direct fixation of the optical signal line 10 at a defined distance to a coupling region of the grating coupler 9 causes. The grating coupler 9 may be made of silicon, of germanium, of glass, or of a polymer in a pressing process, in an etching process, in an imprint process or in a semiconductor process.

5 shows a block diagram of a light refraction device 2 , a converter device 3 and a switch device 4 an embodiment of a receiver according to the invention 1 ,

According to an advantageous development of the invention, at least two lens arrays 6.1 to 6.3 provided, which divide incident light signals LE1 to LE3 from each other in partial light signals. As a result, the field of view can be increased in a simple manner, wherein the sensitivity of the receiver 1 can be almost constant in different partial fields of view. For example, multiple converter arrays 8.1 to 8.3 each combined with a lens array 6.1 to 6.3 on different sides of a receiving module 1 be arranged so as to provide a very large field of view. Ideally, such an optical omnidirectional antenna can be realized.

6 shows a block diagram of an embodiment of a receiver according to the invention 1 ,

According to an advantageous embodiment of the invention is between the converter device 2 and the detector device 5 a phase compensation arrangement 11 to compensate for phase differences of the coupled into different optical signal lines light signals LK1 to LKn provided. Especially with larger lens arrays 6 or when using multiple lens arrays 6 a phase compensation of the individual optical signal lines can be useful in order to prevent mutual weakening or extinction of the coupled-in light signals LK1 to LKn in the further processing of the coupled-in light signals LK1 to LKn.

A phase compensation is understood to mean a measure which equates the phases of the different partial light signals LK1 to LKn relative to one another.

7 shows a block diagram of an embodiment of a receiver according to the invention 1 ,

According to an advantageous embodiment of the invention is between the converter device 3 and the detector device 5 a wavelength-sensitive filter device 12 which has at least one filter element for filtering at least one of the light signals LK1 to LKn coupled into one of the optical signal lines. By means of such a filter device 12 it is possible to remove interfering extraneous signals from the coupled-in light signals LK1 to LKn. In this case, individual or all of the coupled-in light signals LK1 to LKn can be filtered. The filter elements can be switched on and off statically or dynamically. The passband of the filter elements may be in the range of 850 nm, 940 nm, 980 nm, 1330 nm, or 1550 nm, for example. But there are other areas possible. Micro-ring resonators, for example so-called grating-assisted microring resonators, or electrooptically selective materials can be used as filter elements.

8th shows a block diagram of an embodiment of a receiver according to the invention 1 ,

According to an advantageous embodiment of the invention is a second converter device 13 is provided, which comprises a singular or a plurality of second converter elements for coupling out the switched light signal LS1 to LSn from at least one of the optical signal lines, wherein the converter elements are formed such that the decoupled light signal LA1 to LA hits n perpendicular to the detector elements. The second converter elements may be formed as the first converter elements, although the input and the output are reversed.

9 shows a block diagram of an embodiment of a receiver according to the invention 1 , Here, the essential blocks of the receiver are the already described light-breaking device 2 , the already described first converter device 3 , the phase compensation arrangement already described 11 , the switching device already described 4 , the filter device already described 12 , the already described second converter device 13 and the already described detector device 5

10 shows a spatial representation of a converter array 8th , a phase compensation arrangement 11 , a switch device 4 and a detector device 5 an embodiment of a receiver according to the invention 1 , In this case, the first converter device 3 a converter array with a total of nine first converter elements 9.0 to 9.8 on. Each of the converter elements 9.0 to 9.8 is doing with one of the optical signal lines 10.0 to 10.8 each connected to a part of the light refractor, not shown 2 refracted light into the respective optical signal line 10.0 to 10.8 couple.

The switch device 4 includes a total of nine switches 15.0 to 15.8 where each of the switches 15.0 to 15.8 for switching one of the signal lines 10.0 to 10.8 is provided. The switches 15.0 to 15.8 can be used as electro-optical switches, for example 15.0 to 15.8 be educated. The electro-optical switches 15.0 to 15.8 can be based on organic or on inorganic materials. Possible are liquid crystal mixtures, for. B. a mixture of the liquid crystal E44 and polymethyl methacrylate, so-called Dye-Doped Polymer-Stabilized Blue Phase Liquid Crystals (DDPSBP-LC) or silicon-based microwave resonance forums in combination with PIN diodes (English: positive intrinsic negative diode).

According to an advantageous development of the invention, the phase compensation arrangement comprises 11 at least one static delay element 16 which is one of the optical signal lines 10.0 to 10.8 assigned. A static delay element 16 , so a delay element 16 , which constantly causes a defined delay of the respective coupled light signals, is an easy way to equalize the phases of different coupled light signals to each other. In the simplest case, the static delay element is realized by an extension of the optical signal line. However, as static delay elements are also possible, as in 10 shown, micro ring resonators 16 ,

According to an advantageous development of the invention, the phase compensation arrangement comprises 11 at least one dynamically switchable delay element 17.1 to 17.3 which is one of the optical signal lines 10.0 to 10.8 assigned. By using dynamically switchable delay elements 17.1 to 17.3 the accuracy of phase matching can be improved. In particular, the phase matching can thus be carried out as a function of an actual phase difference. The dynamic delay elements 17.1 to 17.3 can be controlled automatically by an electronic control device.

The detector elements 14.0 to 14.2 For example, indium gallium arsenide (InGaAs) may be gallium arsenide (GaAs), silicon (Si), or germanium (Ge). In particular, photodiodes, such as PIN photodiodes, may be used.

According to an advantageous embodiment of the invention are one of the detector elements 14.0 to 14.2 the decoupled light signals from at least two of the optical signal lines 10.0 to 10.8 fed. As a result, the optical signal power at one of the detector elements 14.0 to 14.2 be increased, so that a greater sensitivity can be achieved. So in the example of the 10 the decoupled light signals of the signal lines 10.0 to 10.2 the detector element 14.0 , the decoupled light signals of the signal lines 10.3 to 10.5 the detector element 14.1 and the coupled light signals of the signal lines 10.6 to 10.8 the detector element 14.2 fed.

According to an advantageous development of the invention, the first converter elements 9 one of the first converter arrays 8th and the switches associated with the first converter array 15 and / or the first converter array 8th associated detector elements 14 formed on a plane of a substrate.

According to an advantageous embodiment of the invention, the first converter array 8th associated delay elements 16 . 17 formed at the level of the substrate.

According to an advantageous development of the invention, the first converter array 8th associated filter elements formed on the level of the substrate.

According to an advantageous embodiment of the invention, the first converter array 8th associated second converter elements formed on the level of the substrate.

By forming a plurality of the elements on a common plane of the substrate, the receiver can be manufactured simply and precisely.

• • Ein Linsenarray, bestehend aus einzeln montierten Linsen oder einem zusammenhängendem Linsenverbund. Die Linsen sind z. B. plankonvex, bikonvex, Asphären, Fresnellinsen, CPC oder DTIRC. Das Material kann Glas, Kunststoff, Polymere, Silizium oder Germanium umfassen. Die Herstellung kann mittels Pressverfahren, Spritzguss, Imprint oder Halbleiterprozessen erfolgen. Eine Linse kann Licht auf ein Konverterelement des Konverterarrays oder auf das gesamte Konverterarray fokussieren. Die Linsen können auch direkt auf das Konverterarray aufgebracht werden (ein Linsenelement auf ein Konverterelement, mehrere Linsenelemente auf ein Konverterelement, eine Linse auf mehrere Konverterelemente). Als Alternative zum Linsenarray kann ein optisches Gitter oder ein Diffusor eingesetzt werden.
• • Ein Konverterarray, bestehend aus mehreren Konverterelementen, die jeweils das Licht einer Linse (oder mehrerer Linsen) in je eine optische Faser (auch optische Signalleitung) einkoppeln. Das Konverterelement kann z. B. ein Gitterkoppler, optional mit Taper (direkte Faserfixierung in definiertem Abstand) sein. Bei dem Material kann es sich um Silizium, Germanium, Glas oder um ein Polymer handeln. Die Herstellung kann durch Pressverfahren, Ätzen, Imprint, Halbleiterprozesse erfolgen. Die Anordnung der Konverterelemente kann auf verschiedene Weise beispielsweise auf planen oder gewölbten Flächen erfolgen. Beispielsweise sind kreisförmige Anordnungen oder rechteckigem Muster möglich. Es können mehrere Konverterarrays (jeweils kombiniert mit Linsenarray) an verschiedenen Seiten eines Empfangsmoduls angeordnet werden und so eine zusätzlich vergrößerte Coverage erzeugen (im Idealfall auch als Omnidirektionale Antenne).
• • Eine Schaltmatrix bei der einzelne der n Signalleitung abgeschaltet werden können, um so definierte Bereiche des Empfängers abzuschalten (Reduktion von optischer Leistung oder Störungen). Dazu können z. B. elektro-optische Schalter eingesetzt werden. Elektrooptische Schalter sind ausgebildet über organische oder anorganische Materialien (z. B. Flüssigkritallgemisch (z. B. PMMA/E44 Composite, Dye-Doped Polymer-Stabilized Blue Phase Liquid Crystals (DDPSBP-LC)) oder siliziumbasierte Mikroringresonatoren in Kombination mit PIN Dioden oder andere elektrooptische Schalterprinzipien). Zusätzlich können aus n optischen Signalleitungen mehrere Signalleitungen zusammengeschaltet werden, um so die optische Signalleistung pro Leitung zu erhöhen. Die Anzahl resultierender m Ausgangssignale kann größer gleich eins sein.
• • Ein Detektorarray mit einem bis m Detektoren (z. B. InGaAs, GaAs, Si PIN Photodioden). Das Licht fällt bevorzugt aus dem Konverterarray jeweils senkrecht auf die Detektoroberfläche.
• • Eine Phasenausgleichsanordnung. Bei sehr großen Arrays oder der Anwendung mehrerer Linsen-/Konverterarrays kann ein Phasenausgleich der einzelnen optischen Signalleitungen optional notwendig werden. Der Phasenausgleich kann über statische oder dynamisch zuschaltbare Delayelemente erfolgen. Als statische Verzögerungselemente können unterschiedliche Signallängen oder Mikroringresonatoren verwendet werden. Als dynamische Verzögerungselemente können z. B. über elektrooptische Schalter schaltbare Delayelemente bedarfsgerecht in den Signalweg geschaltet werden.
• • Eine Filtermatrix, mit der jedes der n Signale wellenlängenselektiv gefiltert wird. Die Filter können fest verdrahtet sein oder dynamisch je nach Anwendung zu- oder abgeschaltet werden. Die Wellenlängenselektivität kann z. B. in einem Bereich um 850 nm, 940 nm, 980 nm, 1330 nm, 1550 nm oder in einem anderen Bereich liegen. Die Filter können z. B. mittels Mikroringresonator (z. B. auch Grating-Assisted Mikroringresonator, elektrooptisch selektiver Materialien) realisiert werden. Die Filtermatrix ist optional. Der Phasenausgleich, die Schaltermatrix und die Filtermatrix können auf derselben physikalischen Ebene (gleiches Substrat) wie die Konverterelemente angeordnet sein. Eine zweite Variante besteht in der Aufteilung auf mehrere planare oder andere Substratebenen (mindestens zwei), die z. B. gestackt (übereinander gestapelt) werden können.
• • Ein zweites Konverterarray ist optional und kann das optische Signal senkrecht zu dem Detektorarray leiten. Vom Aufbau können beim zweiten Konverterarray ähnliche Herstellungstechnologien wie beim ersten Konverterarray verwendet werden. Das zweite Konverterarray kann weniger Elemente aufweisen als das erste.

The receiver according to the invention comprises in a preferred embodiment the following components:

• • A lens array consisting of individually mounted lenses or a coherent lens assembly. The lenses are z. Planoconvex, biconvex, aspheres, Fresnel lenses, CPC or DTIRC. The material may include glass, plastic, polymers, silicon or germanium. The production can be carried out by means of compression molding, injection molding, imprinting or semiconductor processes. A lens can focus light on a converter element of the converter array or on the entire converter array. The lenses can also be applied directly to the converter array (a lens element on a converter element, a plurality of lens elements on a converter element, a lens on a plurality of converter elements). As an alternative to the lens array, an optical grating or a diffuser can be used.
• • A converter array, consisting of several converter elements, each of which couple the light of one lens (or several lenses) into one optical fiber (also optical signal line). The converter element can, for. As a grating coupler, optionally with taper (direct fiber fixation in a defined distance) be. The material may be silicon, germanium, glass or a polymer. The production can be done by pressing, etching, imprint, semiconductor processes. The arrangement of the converter elements can be done in various ways, for example on plan or curved surfaces. For example, circular arrangements or rectangular patterns are possible. Several converter arrays (each combined with a lens array) can be arranged on different sides of a receiving module and thus produce an additionally increased coverage (ideally also as an omnidirectional antenna).
• • A switching matrix in which one of the n signal lines can be switched off in order to switch off defined areas of the receiver (reduction of optical power or interference). These can z. B. electro-optical switch can be used. Electro-optical switches are designed using organic or inorganic materials (eg liquid-crystal mixture (eg PMMA / E44 composite, dye-dyed polymer-stabilized blue phase liquid crystals (DDPSBP-LC)) or silicon-based microring resonators in combination with PIN diodes or other electro-optical switch principles). In addition, a plurality of signal lines can be interconnected from n optical signal lines so as to increase the optical signal power per line. The number of resulting m output signals can be greater than or equal to one.
• • A detector array with one to m detectors (eg InGaAs, GaAs, Si PIN photodiodes). The light preferably falls from the converter array in each case perpendicular to the detector surface.
• • A phase compensation arrangement. For very large arrays or the use of multiple lens / converter arrays, a phase compensation of the individual optical signal lines may optionally be necessary. The phase compensation can be done via static or dynamically switchable delay elements. As static delay elements, different signal lengths or micro ring resonators can be used. As dynamic delay elements z. B. switchable via electro-optical switch delay elements can be switched as needed in the signal path.
• • A filter matrix that filters each of the n signals wavelength-selectively. The filters can be hardwired or dynamically turned on or off depending on the application. The wavelength selectivity z. B. in a range around 850 nm, 940 nm, 980 nm, 1330 nm, 1550 nm or in another range. The filters can z. B. by means of micro-ring resonator (eg., Grating-assisted microring resonator, electro-optically selective materials) can be realized. The filter matrix is optional. The phase compensation, the switch matrix and the filter matrix can be arranged on the same physical plane (same substrate) as the converter elements. A second variant consists in the division of several planar or other substrate levels (at least two), the z. B. stacked (stacked) can be.
• A second converter array is optional and can direct the optical signal perpendicular to the detector array. The structure of the second converter array similar manufacturing technologies can be used as the first converter array. The second converter array may have fewer elements than the first.

The advantages of the described invention consist in a combination of small form factor and at the same time application-specific coverage (in extreme cases: omnidirectional receiver). As a result, the optical performance of an optically wireless transmission path with respect to range and orientation of the transmitter and receiver can be increased. In addition, the dynamic range of the described receiver is increased, whereby a data transmission with the same receiver at very short to medium ranges can be easily ensured. Ie. the receiver is not overdriven with a short range (high optical reception power) and with long range (very small reception power) a sufficiently high sensitivity at low (kbit / s) medium (Mbit / s) and high data rates (multi Gbit / s) provided.

LIST OF REFERENCE NUMBERS

1

Optical receiver

2

Light crusher

3

first converter device

4

switch means

5

detector device

6

lens array

7

lens

8th

converter array

9

first converter element

10

optical signal line

11

Phase compensation arrangement

12

filtering device

13

second converter device

14

detector element

15

switch

16

static delay element

17

dynamic delay element

18

second converter array

19

Detector array ni

LE

incident light signal

LT

Partial light signal

LK

coupled light signal

LS

coupled switched light signal

IT

electrical signal

LA

decoupled light signal

Claims (17)

Optical receiver ( 1 ) for an optical wireless communication, with a light refracting device ( 2 ) for breaking an incident light signal (LE) so as to divide the incident light signal (LE) into partial light signals (LT); a first converter device ( 3 ), which a plurality of first converter elements ( 9 ) for coupling one of the partial light signals (LT) in each case an optical signal line ( 10 ), so as to each optical signal line ( 10 ) to generate a coupled light signal (LK); a switch device ( 4 ) containing a singular or a plurality of switches ( 15 ), which in each case in one of the optical signal lines ( 10 ) are arranged and adapted to forward the coupled-in light signal (LK) in a first switch position and to block in a second switch position, so as to generate at least one coupled switchable light signal (LS); and a detector device ( 5 ) with a singular or a plurality of detector elements ( 14 ) for generating an electrical signal (ES) as a function of at least one of the coupled switchable light signals (LS). Receiver ( 1 ) according to the preceding claim, wherein the light-breaking device ( 2 ) at least one lens array ( 6 ) with a plurality of lenses ( 7 ) for breaking the incident light signal (LE). Receiver ( 1 ) according to claim 2, wherein at least two lens arrays ( 6 ) are provided, which divide from different directions incident light signals (LE) each in partial light signals (LT). Receiver ( 1 ) according to one of the preceding claims, wherein the first converter device ( 3 ) at least one converter array ( 8th ) with at least a part of the first converter elements ( 9 ). Receiver ( 1 ) according to one of the preceding claims, wherein the first converter elements ( 9 ) as a grating coupler ( 9 ) are formed. Receiver ( 1 ) according to claim 4 or 5 when referenced back to claim 2 or 3, wherein at least one of the lens arrays ( 6 ) on one of the converter arrays ( 8th ) is arranged. Receiver ( 1 ) according to one of the preceding claims, wherein between the first converter device ( 3 ) and the detector device ( 5 ) a phase compensation arrangement ( 11 ) to compensate for phase differences in different optical signal lines ( 10 ) coupled light signals (LK) is provided. Receiver ( 1 ) according to claim 7, wherein the phase compensation arrangement ( 11 ) at least one static delay element ( 16 ), which is one of the optical signal lines ( 10 ) assigned. Receiver ( 1 ) according to claim 7 or 8, wherein the phase compensation arrangement ( 11 ) at least one dynamically switchable delay element ( 17 ), which is one of the optical signal lines ( 10 ) assigned. Receiver ( 1 ) according to one of the preceding claims, wherein between the first converter device ( 3 ) and the detector device ( 5 ) a wavelength-sensitive filter device ( 12 ) is arranged, which at least one filter element for filtering at least one of the in one of the optical signal lines ( 10 ) has coupled light signals (LK). Receiver ( 1 ) according to one of the preceding claims, wherein a second converter device ( 13 ) is provided which comprises a singular or a plurality of second converter elements for generating one from at least one of the optical signal lines ( 10 ), wherein the second converter elements are formed so that the coupled-out light signal (LA) perpendicular to the detector elements ( 14 ) meets. Receiver ( 1 ) according to one of the preceding claims, wherein one of the detector elements ( 14 ) the decoupled light signals (LA) of at least two of the optical signal lines ( 10 ) can be supplied. Receiver ( 1 ) according to one of the preceding claims, wherein the first converter elements ( 9 ) one of the first converter arrays ( 8th ) and the first converter array ( 8th ) associated switch ( 15 ) are formed on one or more levels of a substrate. Receiver ( 1 ) according to claim 13 when referenced back to claim 4, wherein the said first converter array ( 8th ) associated detector elements ( 14 ) are formed on one or more levels of the substrate. Receiver ( 1 ) according to claim 13 or 14 when referenced back to claim 8 or 9, wherein the said first converter array ( 8th ) associated delay elements ( 16 . 17 ) are formed on the substrate. Receiver ( 1 ) according to any one of claims 13 to 15 when referenced back to claim 10, wherein the first converter array ( 8th ) associated filter elements are formed on the substrate. Receiver ( 1 ) according to any one of claims 13 to 16 when referred back to claim 11, wherein the said first converter array ( 8th ) associated second converter elements are formed on the substrate.

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