DE102006004026A1 - Optical switch, has light emitting diode producing electromagnetic radiation that is formed and ranged in such a manner that radiation causes material present in fiber glass section to change permeability for optical signal - Google Patents

Abstract

The switch has a fiber glass section (S) conducting an optical signal, and a light emitting diode (L) producing an electromagnetic radiation. The radiation is formed and ranged in such a manner that the radiation causes a material present in the fiber glass section to change permeability for the optical signal. The permeability of the optical signal is reversibly changed, and the fiber glass section is completely or partially composed of a material. An independent claim is also included for a method for operating an optical switch.

Description

The The invention relates to an optical switch and a method for Operation of an optical switch.

A Require a variety of applications in optical fiber technology optical switches. These serve to make an optical fiber like a fiber between the states transparent and opaque, that is opaque to switch. If the switch is switched to transparent, optical signals are transmitted. Is the switch on the other hand? switched opaque, the optical signals are blocked.

Of the Term transparent means with respect to the optical switch, that the optical signals the optical switch at least so can happen that subsequent devices consider the signals as transmitted. The switch must do this not completely be transparent, but can attenuate the optical signals.

Of the Term opaque means with respect to the optical switch the optical signals at least so block the optical switch be that subsequent devices do not consider the signals to be transmitted or stop recording can. The switch does not have to be completely opaque but only has to attenuate the optical signals sufficiently.

• – Mechanischer Schalter: An einer Verbindungsstelle zwischen zwei Glasfasern wird das Ende einer der Glasfasern mechanisch von seinem passenden Gegenstück getrennt. Hierdurch wird der Schalter auf opak geschaltet. Führt die Mechanik die Enden der Glasfasern wieder zusammen, ist der Schalter transparent.

The following solutions for constructing optical switches are known:

• - Mechanical switch: At a juncture between two glass fibers, the end of one of the glass fibers is mechanically separated from its mating counterpart. This switches the switch to opaque. If the mechanism brings the ends of the glass fibers back together, the switch is transparent.

• – Mach-Zehnder-Interferometer: Hierbei gibt es die Varianten einer thermischen oder elektro-optischen Schaltung. Diese Lösung weist den Vorteil auf, dass integrierte Bauteile hergestellt werden können, die hohe Schaltgeschwindigkeiten erlauben. Nachteile der Lösung bestehen jedoch darin, dass die optische Bandbreite für die optischen Signale begrenzt ist und dass permanent Energie benötigt wird.
• – Elektroabsorptionsmodulatoren: Ähnlich zum Mach-Zehnder-Interferometer lassen sich hier integrierte Bauteile herstellen, die hohe Schaltgeschwindigkeiten ermöglichen. Ebenfalls analog zum Interferometer besteht auch hier der Nachteil, dass eine anhaltende Energieversorgung notwendig ist.

In addition to the advantages of a low insertion loss, a very good extinction and a large optical bandwidth for the optical signals, this solution has the disadvantage that a mechanism must be realized. On the one hand, this mechanism makes the miniaturization of the switch difficult and, on the other hand, limits a switching speed. Insertion loss refers to the attenuation, ie reduction of the intensity that causes a component inserted into a beam path with passing radiation.

• - Mach-Zehnder interferometer: There are the variants of a thermal or electro-optical circuit. This solution has the advantage that integrated components can be manufactured that allow high switching speeds. Disadvantages of the solution, however, are that the optical bandwidth for the optical signals is limited and that permanent energy is needed.
• - Electroabsorption modulators: Similar to the Mach-Zehnder interferometer, integrated components can be produced here that allow high switching speeds. Also analogous to the interferometer, the disadvantage here is that a sustained power supply is necessary.

The The object underlying the invention is to provide an optical Specify switch, on the one hand realizes a large optical bandwidth and wherein in at least one state of the optical switch This can be operated energy-free.

These The object is achieved by an optical switch according to claim 1 and a method for operating an optical switch according to claim 9.

Of the optical switch has an optical fiber path for optical line Signals and a radiation source for generating electromagnetic radiation on. These are designed and arranged such that the electromagnetic radiation causes a material present in the optical fiber route to his permeability for the to change optical signals.

The Fiber optic path is designed to be optical signals at least in one direction from one end to the other can. For example, the optical fiber route realized as a glass fiber become.

The Optical fiber route can be made entirely of the material or contain the material. For example, the material may be in be introduced another material.

The Radiation source is at least on and off. It exists also the possibility that the intensity the electromagnetic radiation of the radiation source controllable is. As sources of radiation are, for example, light bulbs, LEDs (light-emitting diodes), Fluorescent lamps, plasma lamps or laser diodes in question.

The electromagnetic radiation generated by the radiation source is at least partially in such a wavelength range that the material of the optical fiber route upon irradiation with the electromagnetic Radiation of the radiation source to a change in permeability is initiated.

By permeability of the material is meant the property of the material, the optical sig nale happen. If the optical switch is switched to transparent, the permeability is higher than when the switch is set to opaque.

Of the absolute value of permeability in the transparent state of the switch is in particular more than 80%. In the opaque state of the switch is the permeability less than in the transparent state of the switch, in particular less as 20%, preferably 10% and in a particular embodiment 5%.

One Advantage of the optical according to the invention Switch is that in one of its two states, i. in the transparent or in the opaque state no energy supply needed. Another advantage is its low insertion loss.

Of the optical switch also has the advantage that it has a high optical bandwidth and a large transparency for any optical modulation formats such as on-off keying or phase shift keying. Another advantage of the optical switch is its low level Production costs.

Of the optical switch has the further advantage that no electrical Connection from outside to the optical fiber route is necessary.

The permeability is preferably reversible by the electromagnetic radiation changed. This means that the material for any intensity of the electromagnetic Radiation each having a value of the permeability. Upon irradiation with the electromagnetic radiation, the material takes the respective Value in essence. This means that, for example, the permeability after turning off the radiation source again substantially takes the value that they have before turning on the radiation source would have. This ensures that the switch can be used multiple times is.

In an advantageous embodiment and development of the invention the optical fiber path consists entirely of the material. Of the Advantage of this structure is that the optical fiber route easier is to produce. Another advantage is an increased homogeneity of the permeability.

In a further advantageous embodiment and development of Invention consists of the optical fiber path partially made of the material. This can for example be realized by the material in Particles in a base material of the optical fiber route such. Glass is introduced. This construction possibility has the advantage that better control of properties of the optical switch is made possible in its manufacture. Such a property For example, the difference in permeability between the transparent one and the opaque state of the switch.

In an advantageous embodiment and development of the invention the radiation source is an LED (Light Emitting Diode). This has the advantage of having an LED as a small, integrated element can be produced. Furthermore, an LED has the advantage that the wavelength range the electromagnetic radiation emitted by the LED, narrow and precise. Another advantage of the LED exists in their high switching speed. Continue to exist with an LED the possibility the intensity infinitely variable.

In an advantageous embodiment and development of the invention the electromagnetic radiation has ultraviolet radiation. This means that the material changes its permeability at an irradiation with ultraviolet radiation. It is useful if The material is designed in such a way that it contributes to its permeability Irradiation with electromagnetic radiation other than Ultraviolet radiation does not or only slightly changes. Appropriately points the electromagnetic radiation generated by the radiation source Shares of ultraviolet radiation on or consists of completely ultraviolet radiation.

Of the Advantage of this embodiment is that the optical signals not or only slightly the permeability influence. Thus, no or only by the optical signals little influence on the state of the switch taken.

In an alternative embodiment and development of the invention the electromagnetic radiation has visible light. This means that the material changes its permeability at an irradiation with visible light. Expediently, that of the radiation source generated electromagnetic radiation shares of visible light on or completely exists out of visible light. This has the advantage that the homogeneity of permeability the optical fiber route increases is.

With Ultraviolet radiation is the area of electromagnetic Radiation with wavelengths smaller as 380nm and larger than 10nm meant. With visible light is the range of electromagnetic Radiation with wavelengths less than 780nm and larger than 380nm meant. As the mentioned limits, especially at 780nm and 380nm from sight of the human eye, they are not exactly defined, but as approximate values to understand.

In an advantageous embodiment and Wei Training the invention is the electromagnetic radiation monochromatic. This means that the radiation has essentially one wavelength. Essentially, this means that the radiation nevertheless covers a wavelength range, but that only a small proportion of the radiation lies outside of a narrow interval around the wavelength. For example. For example, less than 0.1% of the radiation could be outside a 2nm wide interval around the wavelength of, for example, 420nm, ie, from 419nm to 421nm.

In an advantageous embodiment and development of the invention The electromagnetic radiation causes the material to his permeability to increase. In this case needed the optical switch advantageously in its opaque state none Power supply.

In an alternative embodiment and development of the invention The electromagnetic radiation causes the material to his permeability to lower. In this case needed the optical switch advantageous in its transparent state no power supply.

At the Method of operating an optical switch becomes switching the optical switch in a first state irradiation of the Optical fiber route made with electromagnetic radiation and switching the optical switch in a second Condition prevents radiation.

in this connection it is appropriate, the Irradiation caused by a shutdown of the radiation source. Alternatively or in addition The irradiation is also by the introduction of a blocking element (Shutter) prevented.

Further Details and advantages of the invention will be apparent from a explained in the drawing illustrated embodiment. there shows:

1 an optical switch with a photochromic fiber optic element and an LED.

In the schematic representation according to 1 is an optical switch, consisting of a fiber optic link S and an LED L, connected between two glass fibers G. The LED L is designed as a UV-LED. When switched on it emits ultraviolet radiation E, in this example with the wavelength of about 360nm.

The Glass fiber section S corresponds in structure mainly to the glass fibers G. In contrast to these, however, in the fibers of the optical fiber link S a phototropic material introduced. This lowers on irradiation with the ultraviolet radiation E its permeability in a reversible manner. Therefor are small particles of the phototropic material in the fibers of the Fiberglass track S introduced.

Should the optical switch passes optical signals, i. in transparent Be state, so the LED L is off. In this condition Therefore, the switch consumes no energy. Should the switch open impermeable, i.e. opaque, the LED L is switched on. she then generates the ultraviolet radiation E, whereby the permeability the optical fiber link S decreases and thus the optical signals sufficient attenuates, that they can be considered as blocked.

A alternative embodiment results from the fact that the material upon irradiation with visible light changes its permeability. In In this embodiment, an LED L is used, which also emitted visible light, in this alternative with a wavelength of 590nm. It is expedient, the Material should be designed so that when exposed to such visible Light reacts that the optical signals themselves not or only slightly to a change the permeability lead.

In an alternative embodiment of the optical switch, the optical fiber link S is substantially as constructed as the glass fibers G. That means, it is structured that it is a line of optical signals analogous to that of the glass fibers G allows, for example, with respect to the number of parallel-guided signals or the possible Frequency spectrum. In contrast to the glass fibers G is the signal-conducting Part of the fiber optic section S, however, completely made of a material whose permeability is low, as long as no irradiation takes place. Upon irradiation becomes his permeability elevated.

hereby The result is an optical switch that switches off when the LED L is off opaque state and thus in the opaque state requires no energy.

Another alternative embodiment of the optical switch results from the use of a material that irreversibly alters its transmissivity. In this case, it is expedient if the material has a high permeability. The signal-conducting part of the optical fiber link S can in turn be made entirely or partially of the material. The resulting optical switch thus reacts once to the corresponding irradiation and thus can serve, for example, as a correspondence of an electrical fuse. For such an application, it is also useful if the material reacts to such electromagnetic radiation, which also for the optical signals is used.

Further variants arise in that between the fiber optic path S and the radiation source a shutter is attached. This can be opened to the irradiation allow the fiber optic path S through the radiation source and closed to prevent irradiation. Here is it is possible that the radiation source is operated permanently. This variant allows it, for example, in a field consisting of a variety of optical switch only to use a radiation source. The circuit of the individual switches of the field then takes place the shutter takes place. It is also expedient here, no LED L as a radiation source use, but, for example, a light bulb or fluorescent lamp.

Claims (10)

Optical switch with a fiber optic path to the Conduction of optical signals and a radiation source for generation electromagnetic radiation configured and arranged in such a way are that the electromagnetic radiation in the fiber optic path existing material causes its permeability for the to change optical signals. An optical switch according to claim 1, wherein the transmissivity of the material is reversibly changeable. An optical switch according to claim 1 or 2, wherein the optical fiber route completely consists of the material. An optical switch according to claim 1 or 2, wherein the optical fiber path is partially made of the material. An optical switch according to any one of the preceding claims, wherein the radiation source is an LED (Light Emitting Diode). An optical switch according to any one of the preceding claims, wherein the electromagnetic radiation ultraviolet radiation and / or has visible light. An optical switch according to any one of the preceding claims, wherein the electromagnetic radiation is monochromatic. An optical switch according to any one of the preceding claims, wherein the electromagnetic radiation causes the material to permeability to increase or lower. Method for operating an optical switch according to one of the preceding claims, wherein switching of the optical switch in a first Condition irradiation of the optical fiber route with the electromagnetic Radiation is made and switching of the optical switch in a second state, the irradiation is prevented. The method of claim 9, wherein by a shutdown the radiation source and / or by the introduction of a blocking element the irradiation is prevented.