Devices with controllable light wave guides

Claim 3

A device according to claim 1, wherein the multi-layer structure is combined with semiconductor substrates and layers (16, 14, 12, 18, 24).

Claim 4

A light switching device comprising at least one light wave guide composed of an extremely thin film multi-layer structure forming a multi-quantum well (MQW) said device being embodied in a block (10) with at least one input (IN) and at least two outputs (LOI, LOII) and a control electrode (26) which receives a variable voltage which is used to vary an electric field in the multi-quantum well whereby to alter the refractive index of the well to switch the light from one ouput (LOII-) to the other (LOI) and vice versa.

Claim 5

A light switching device comprising at least one light wave guide composed of an extremely thin film multi-layer structure forming a multi-quantum well (MQW) said device being embodied in a block (10) with at least one input (IN) and at least two outputs (LOI, LOII) and a control electrode (26) which receives a variable voltage which is used to vary an electric field in the multi-quantum well whereby to alter the refractive index of the well to switch the light from one ouput (LOII-) to the other (LOI) and vice versa.

Claim 6

A light switching device comprising first and second light wave guides which intersect one another over a region composed of at least one extremely thin film multi-layer structure forming a multi-quantum well (MQW), an input (Lin) for introducing light into the device and outputs (LOI, LOII) for emitting the light from the device in different directions and a control electrode (26) which serves to create an electric field in the multi-quantum well (MQW) which can be altered to change the refractive index of the intersecting region of the guides in response to the voltage applied to the control electrode to change the output from which light is emitted.

Claim 7

A light switching device comprising first and second light wave guides which intersect one another over a region composed of at least one extremely thin film multi-layer structure forming a multi-quantum well (MQW), an input (Lin) for introducing light into the device and outputs (LOI, LOII) for emitting the light from the device in different directions and a control electrode (26) which serves to create an electric field in the multi-quantum well (MQW) which can be altered to change the refractive index of the intersecting region of the guides in response to the voltage applied to the control electrode to change the output from which light is emitted.

Claim 8

A device according to claim 3 or 4 wherein the voltage applied to the electrode to select one output is zero and the voltage applied to the electrode to select the other output is a non-zero value.

Claim 9

A directional coupler for changing the path of light inputs to one or other of two outputs; said device comprising first and second light guides each composed of an extremely thin film multi-layer structure forming a multi-quantum well (MQW), the guides having regions extending parallel to one another wherein each guide has a control electrode (30, 32) to which a voltage is applied to create an electric field in the multi-quantum well of the guide which can be varied to alter the propogation constant of the guide whereby the voltages are controlled to cause light to transfer from one guide to the other to emerge from one or other of the outputs.

Claim 10

A directional coupler for changing the path of light inputs to one or other of two outputs; said device comprising first and second light guides each composed of an extremely thin film multi-layer structure forming a multi-quantum well (MQW), the guides having regions extending parallel to one another wherein each guide has a control electrode (30, 32) to which a voltage is applied to create an electric field in the multi-quantum well of the guide which can be varied to alter the propogation constant of the guide whereby the voltages are controlled to cause light to transfer from one guide to the other to emerge from one or other of the outputs.

Claim 11

A light switching system comprising a first group of light inputs (INPUT 1) connected via light wave guides to a first group of light outputs (OUT-1), a second group of light inputs (INPUT 2) connected via light wave guides to second group of light outputs (OUT 2), wherein the light guides intersect (SW) and include extremely thin film multi-layer structures forming multi-quantum wells (MQW) the intersecting regions having control electrodes for receiving voltages used to create an electric field in the multi-quantum wells which can be altered to connect selectively any one of the first or second groups of light inputs to any one of the first and second groups of light outputs.

Claim 12

A light switching system comprising a first group of light inputs (INPUT 1) connected via light wave guides to a first group of light outputs (OUT-1), a second group of light inputs (INPUT 2) connected via light wave guides to second group of light outputs (OUT 2), wherein the light guides intersect (SW) and include extremely thin film multi-layer structures forming multi-quantum wells (MQW) the intersecting regions having control electrodes for receiving voltages used to create an electric field in the multi-quantum wells which can be altered to connect selectively any one of the first or second groups of light inputs to any one of the first and second groups of light outputs.

Claim 13

A light communications system comprising a plurality of light inputs (IN) connected via switchable light wave guides each composed of an extremely thin film multi-layer structure forming a multi-quantum well (MQW) with a common communication link, a plurality of light outputs (OUT) connected via switchable light wave guides each composed of an extremely thin film multi-layer structure forming a multi-quantum well (MQW) with said communication link, wherein the switchable light wave guides employ control electrodes to create electric fields in the multi-quantum wells which are altered to connect any one of inputs to a selected output.

Claim 14

A light communications system comprising a plurality of light inputs (IN) connected via switchable light wave guides each composed of an extremely thin film multi-layer structure forming a multi-quantum well (MQW) with a common communication link, a plurality of light outputs (OUT) connected via switchable light wave guides each composed of an extremely thin film multi-layer structure forming a multi-quantum well (MQW) with said communication link, wherein the switchable light wave guides employ control electrodes to create electric fields in the multi-quantum wells which are altered to connect any one of inputs to a selected output.

Claim 15

A system according to claim 8, wherein the switchable guides are synchronously operated to realise time sharing multiple light communications.

Claim 16

A light communications system comprising a first light transmitter (LTI) connected via a first switchable light wave guide composed of an extremely thin film structure forming a multi-quantum well (MQ) with a common communications link, a first light receiver (LRI) connected via a second switchable light wave guide composed of an extremely thin film structure forming a multi-quantum well (MQW) with said communications link, a second light transmitter (LT2) connected via the second switchable light wave guide with said communications link and a second light receiver (LR2) connected via the first switchable light wave guide with said communications link, wherein the switchable light wave guides employ control electrodes to create electric fields in the multi-quantum wells which are altered to connect the first transmitter (LT1) to the first receiver (LTI) or the second transmitter (LT2) to the second receiver (LR2).

Claim 17

A light communications system comprising a first light transmitter (LTI) connected via a first switchable light wave guide composed of an extremely thin film structure forming a multi-quantum well (MQ) with a common communications link, a first light receiver (LRI) connected via a second switchable light wave guide composed of an extremely thin film structure forming a multi-quantum well (MQW) with said communications link, a second light transmitter (LT2) connected via the second switchable light wave guide with said communications link and a second light receiver (LR2) connected via the first switchable light wave guide with said communications link, wherein the switchable light wave guides employ control electrodes to create electric fields in the multi-quantum wells which are altered to connect the first transmitter (LT1) to the first receiver (LTI) or the second transmitter (LT2) to the second receiver (LR2).

Claim 18

A system according to claim 10, wherein the first transmitter (LT1) is combined with the second receiver (LR2) and the first receiver (LR1) is combined with the second transmitter (LT2) and the light wave guides are operated synchronously to realise two-way light communications.