# US 2013/0156429 A1 · Optical-electrical switching node > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2013/0156429 A1 - Document ID: US20130156429A1 - Status: Published application - Kind: A1 - Application number: 13/818,631 - Filed: 2010-08-25 - Published: 2013-06-20 - Earliest claimed: 2010-08-25 - Assignees: Telefonaktiebolaget L M Ericsson - Inventors: Bengt-Erik Olsson - Web page: https://patentgrep.com/patent/US20130156429A1 ## CPC - H04Q 11/0005: {Switch and router aspects} - H04Q 2011/0007: {Construction} - H04Q 2011/0035: {using miscellaneous components, e.g. circulator, polarisation, acousto/thermo optical} - H04Q: SELECTING (switches, relays, selectors H01H; wireless communication networks H04W) ## Abstract An electro-optical switch (170) for receiving N data streams optically, each of said N data streams having an amplitude and a phase and each being located at an optical centre frequency FO1+RFM, where FO1 is a first optical modulation frequency and RFM is a signal centre frequency. The electro-optical switch is arranged to convert the N data streams to electrical data signals at the data stream's signal centre frequency RFM, the electrical data signals having the amplitude and phase of the optical data stream. The electro-optical switch is further arranged to convert electrical data signals to optical output signals at optical centre frequency FO2+RFOut with the amplitude and phase of the first electrical data signal maintained, and to transmit the optical output signals, with RFM and RFOut, being equal to or different from each other, and FO1 and FO2 also being equal to or different from each other. ## Claims ### Claim 1 An electro-optical switch configured to; (i) receive N data streams on an optical link from a first node in a communications system, each of said N data streams having an amplitude and a phase and each being located at an optical centre frequency FO1+RFM, where Fo1 is a first optical modulation frequency and RFM is a signal centre frequency, where M is an integer which ranges from 1 to N for the N data streams; (ii) convert at least a first of the N data streams on said optical link to a first electrical data signal at the data stream's signal centre frequency RFM, the first electrical data signal having the amplitude and phase of the first data stream on the optical link; (iii) convert the first electrical data signal to a first optical output signal at an optical centre frequency FO2+RFOUT with the amplitude and phase of the first electrical data signal maintained, where FO2 is a second optical modulation frequency; and (iv) forward the first optical output signal to a second node in the communications system, with RFM, and RFOUT being equal to or different from each other, and FO1 and FO2 also being equal to or different from each other. ### Claim 2 (depends on 1) The electro-optical switch of claim 1, comprising a control unit configured to check which optical frequencies are available for transmissions to the second node, and to cause the switching node to choose RFOUT to be equal to one of those available frequencies. ### Claim 3 (depends on 1) The electro-optical switch claim 1, further configured to transmit data signals to local users, so that one or more of the N data streams which are converted to electrical data signals can be transmitted to a local user. ### Claim 4 (depends on 1) The electro-optical switch of claim 1, further configured to receive a data signal from a local user, and to convert such a data signal to an optical output signal at a centre frequency RFout with the amplitude and phase of the electrical data signal maintained, and to forward the optical output signal to the second node in the communications system. ### Claim 5 (depends on 3) The electro-optical switch of claim 3, further configured to transmit/receive said data signals to/from a local user as a baseband signal. ### Claim 6 (depends on 3) The electro-optical switch of claim 3, further configured to transmit/receive said data signals to/from a local user as an electrical signal on a Radio Frequency, with an amplitude and a phase. ### Claim 7 (depends on 1) The electro-optical switch of claim 1, comprising at least one optical-to-electrical field converter adapted to receive an optical input signal which has a bandwidth B and to output first and second electrical signals which correspond to respective first and second polarizations in the optical input signal, where each of the first and second electrical signals carries N data channels at respective signal centre frequencies f1-N, the electro-optical switch also comprising a networking unit adapted for receiving as input signals the first and second electrical signals from the optical-to-electrical field converter, the electro-optical switch also comprising at least one electrical-to-optical transmitter adapted to receive a first and a second electrical output signal from the networking unit, and further being adapted to combine the two electrical signals into one optical output signal with a first and a second polarization, each of which polarization corresponds to one of said electrical signals. ### Claim 8 (depends on 2) The electro-optical switch of claim 2, wherein the control unit is further configured to control the networking unit to remove, or to replace with another data channel, one or more of said N data channels in each of the two electrical input signals, and to output two electrical signals which each carries an amount of data channels which is equal or greater or smaller than N and centre frequencies which are different or equal to f1-N.