Remote control device of acousto-optic tunable filter and optical transmission system containing equalizer using acousto-optic tunable filter and optical transmission system containing optical add/drop multiplexer using acousto-optic tunable filter

• US 20020097467A1
• Filed: 02/07/2002
• Published: 07/25/2002
• Est. Priority Date: 01/30/1998
• Status: Active Grant

• Current Assignee: Fujitsu Limited
• Original Assignee: Fujitsu Limited
• Inventors: Terahara, Takafumi, Chikama, Terumi
• Granted Patent: US 6,647,211 B2
• Time in Patent Office: Days
• US Class Current: 398/107
• CPC Class Codes: H04B 10/077 using a supervisory or additional signal
• CPC Class Codes: H04B 10/07955 Monitoring or measuring power
• CPC Class Codes: H04J 14/02 Wavelength-division multiplex systems
• CPC Class Codes: H04J 14/0206 Express channels arrangements
• CPC Class Codes: H04J 14/021 Reconfigurable arrangements, e.g. reconfigurable optical add/drop multiplexers [ROADM] or tunable optical add/drop multiplexers [TOADM]
• CPC Class Codes: H04J 14/0212 using optical switches or wavelength selective switches [WSS]
• CPC Class Codes: H04J 14/0213 Groups of channels or wave bands arrangements

Abstract

The invention provides a remote control device of an acousto-optic tunable filter, which comprises an acousto-optic tunable filter interpolated in an optical transmission line, capable of controlling an output state of an input light signal by being supplied with a surface acoustic wave control signal through a control port; a surface acoustic wave control signal source to generate the surface acoustic wave control signal, which is provided at a remote place from the acousto-optic tunable filter; and a control unit that receives an information of the surface acoustic wave control signal from the surface acoustic wave control signal source through remote transmission means, and supplies the surface acoustic wave control signal to the control port of the acousto-optic tunable filter. According to this invention, the scale of the device using the acousto-optic tunable filter becomes enlarged, the power consumption is increased; and the man power required for the maintenance of the devices can be reduced, and the remote control of the acousto-optic tunable filter can be achieved.

Claims

1. A remote control device of an acousto-optic tunable filter, comprising:

an acousto-optic tunable filter interpolated in an optical transmission line, capable of controlling an output state of an input light signal by being supplied with a surface acoustic wave control signal through a control port;

a surface acoustic wave control signal source to generate the surface acoustic wave control signal, which is provided at a remote place from the acousto-optic tunable filter; and

a control unit that receives an information of the surface acoustic wave control signal from the surface acoustic wave control signal source through remote transmission means, and supplies the surface acoustic wave control signal to the control port of the acousto-optic tunable filter.

2. A remote control device of an acousto-optic tunable filter, as claimed in claim 1, wherein:

the remote control device further comprises a surface acoustic wave light control signal transmitting unit that outputs to convert the surface acoustic wave control signal from the surface acoustic wave control signal source into a surface acoustic wave light control signal; and

the control unit contains a receiving unit that receives the surface acoustic wave light control signal from the surface acoustic wave light control signal transmitting unit and converts the surface acoustic wave light control signal into the surface acoustic wave control signal, and a driving unit that supplies the surface acoustic wave control signal received by the receiving unit to the control port of the acousto-optic tunable filter.

3. A remote control device of an acousto-optic tunable filter, as claimed in claim 2, wherein:

the remote control device further comprises wavelength multiplexing means that multiplex the surface acoustic wave light control signal from the surface acoustic wave light control signal transmitting unit with a light signal transmitted through the optical transmission line into a wavelength division multiplexed signal, and supplies the wavelength division multiplexed signal to the optical transmission line; and

the receiving unit of the control unit contains a wavelength selecting filter to selectively receive the surface acoustic wave light control signal out of the surface acoustic wave light control signal and the light signal that are transmitted through the optical transmission line in the wavelength division multiplexed signal, and a photoelectric transducing unit to convert the surface acoustic wave light control signal selected by the wavelength selecting filter into an electric signal.

4. A remote control device of an acousto-optic tunable filter, as claimed in claim 2, wherein:

the remote control device further comprises superposed modulation means that superposedly modulate a light signal transmitted through the optical transmission line and the surface acoustic wave light control signal from the surface acoustic wave light control signal transmitting unit, and supplies the modulated signal to the optical transmission line; and

the receiving unit of the control unit contains a photoelectric transducing unit that converts the light signal with the surface acoustic wave light control signal superposedly modulated into an electric signal so as to selectively receive the surface acoustic wave light control signal out of the surface acoustic wave light control signal and the light signal that are transmitted through the optical transmission line in the superposed modulation signal, and an electric filter that filters a component of the surface acoustic wave control signal from the electric signal converted by the photoelectric transducing unit.

5. A remote control device of an acousto-optic tunable filter, as claimed in claim 1, wherein the remote control device further comprises:

a monitor unit that monitors a light signal information on the output of the acousto-optic tunable filter through the optical transmission line at a remote place, and

a surface acoustic wave control signal control unit that controls a state of the surface acoustic wave control signal from the surface acoustic wave control signal source on the basis of a monitor information from the monitor unit.

6. A remote control device of an acousto-optic tunable filter, as claimed in claim 1, wherein the remote control device comprises:

a first light signal transmit receive terminal to transmit a light signal to an upward optical transmission line and receive a light signal from a downward optical transmission line, and a second light signal transmit receive terminal to transmit a light signal to the downward optical transmission line and receive a light signal from the upward optical transmission line, while the acousto-optic tunable filter is interpolated in one optical transmission line of the upward optical transmission line and the downward optical transmission line, and

a monitor unit placed on the side of one light signal transmit receive terminal positioned on the side of an output of the acousto-optic tunable filter, of the first light signal transmit receive terminal and the second light signal transmit receive terminal, which monitors a light signal information on the output of the acousto-optic tunable filter through the one optical transmission line;

and the remote control device comprises, on the side of one light signal transmit receive terminal positioned on the side of an input of the acousto-optic tunable filter, of the first light signal transmit receive terminal and the second light signal transmit receive terminal,

a monitor information receiving unit to receive a monitor information from the monitor unit through the other optical transmission line of the upward optical transmission line and the downward optical transmission line,

the surface acoustic wave source,

a surface acoustic wave control signal control unit to control a state of the surface acoustic wave control signal from the surface acoustic wave control signal source on the basis of the monitor information received by the monitor information receiving unit, and a surface acoustic wave light control signal transmitting unit to convert the surface acoustic wave control signal from the surface acoustic wave control signal source into a surface acoustic wave light control signal, and to transmit the surface acoustic wave light control signal through the one optical transmission line;

and the remote control device wherein;

the control unit contains a receiving unit that receives the surface acoustic wave light control signal from the surface acoustic wave light control signal transmitting unit and converts the surface acoustic wave light control signal into the surface acoustic wave control signal, and a driving unit that supplies the surface acoustic wave control signal received by the receiving unit to the control port of the acousto-optic tunable filter, and

the receiving unit of the control unit receives the surface acoustic wave light control signal from the surface acoustic wave light control signal transmitting unit through the one optical transmission line, and converts the surface acoustic wave light control signal into the surface acoustic wave control signal.

7. A remote control device of an acousto-optic tunable filter, as claimed in claim 1, wherein the remote control device comprises:

a first light signal transmit receive terminal to transmit a light signal to an upward optical transmission line and receive a light signal from a downward optical transmission line, and a second light signal transmit receive terminal to transmit a light signal to the downward optical transmission line and receive a light signal from the upward optical transmission line, while the acousto-optic tunable filter is interpolated in one optical transmission line of the upward optical transmission line and the downward optical transmission line;

and the remote control device comprises, on the side of one light signal transmit receive terminal positioned on the side of an output of the acousto-optic tunable filter, of the first light signal transmit receive terminal and the second light signal transmit receive terminal,

a monitor unit to monitor a light signal information on the output of the acousto-optic tunable filter through the one optical transmission line,

the surface acoustic wave source,

a surface acoustic wave control signal control unit to control a state of the surface acoustic wave control signal from the surface acoustic wave control signal source on the basis of the monitor information received by the monitor information receiving unit, and a surface acoustic wave light control signal transmitting unit to convert the surface acoustic wave control signal from the surface acoustic wave control signal source into a surface acoustic wave light control signal, and to transmit the surface acoustic wave light control signal through the other optical transmission line of the upward optical transmission line and the downward optical transmission line;

and the remote control device wherein;

the control unit contains a receiving unit that receives the surface acoustic wave light control signal from the surface acoustic wave light control signal transmitting unit and converts the surface acoustic wave light control signal into the surface acoustic wave control signal, and a driving unit that supplies the surface acoustic wave control signal received by the receiving unit to the control port of the acousto-optic tunable filter, and

the receiving unit of the control unit receives the surface acoustic wave light control signal from the surface acoustic wave light control signal transmitting unit through the other optical transmission line, and converts the surface acoustic wave light control signal into the surface acoustic wave control signal.

8. A remote control device of an acousto-optic tunable filter, as claimed in claim 2, wherein, in order to make the acousto-optic tunable filter function as an equalizer:

the receiving unit of the control unit receives the surface acoustic wave light control signal from the surface acoustic wave light control signal transmitting unit on the side of the output of the acousto-optic tunable filter, and converts the surface acoustic wave light control signal into the surface acoustic wave control signal; and

the driving unit of the control unit regulates a power of the surface acoustic wave control signal received by the receiving unit, and thereafter, supplies the regulated power to the control port of the acousto-optic tunable filter.

9. A remote control device of an acousto-optic tunable filter, as claimed in claim 8, wherein:

the receiving unit of the control unit is provided with a photoelectric transducing unit to convert the surface acoustic wave light control signal from the surface acoustic wave light control signal transmitting unit into an electric signal on the side of the output of the acousto-optic tunable filter, and a plurality of filters to extract a plurality of the surface acoustic wave control signals from the electric signal converted by the photoelectric transducing unit; and

the driving unit of the control unit is provided with a power regulating unit to regulate powers of the surface acoustic wave control signals from the filters, and a driving amplifying unit to supply the surface acoustic wave control signal of which power is regulated by the power regulating unit to the control port of the acousto-optic tunable filter.

10. A remote control device of an acousto-optic tunable filter, as claimed in claim 8, wherein:

the receiving unit of the control unit is provided with a wavelength selecting filter to selectively output a plurality of the surface acoustic wave light control signals of different wavelengths out of the surface acoustic wave light control signal from the surface acoustic wave light control signal transmitting unit on the side of the output of the acousto-optic tunable filter, a plurality of photoelectric transducing units to convert the surface acoustic wave light control signals selected by the wavelength selecting filter into electric signals, and a plurality of filters in correspondence with a plurality of the photoelectric transducing units to extract a plurality of the surface acoustic wave control signals out of the electric signals converted by the photoelectric transducing units; and

the driving unit of the control unit is provided with a power regulating unit to regulate powers of the surface acoustic wave control signals from the filters, and a driving amplifying unit to supply the surface acoustic wave control signal of which power is regulated by the power regulating unit to the control port of the acousto-optic tunable filter.

11. A remote control device of an acousto-optic tunable filter, as claimed in claim 1, wherein, in order to make the acousto-optic tunable filter function as a optical add/drop multiplexer:

one input port of two input ports of the acousto-optic tunable filter is served as an input light signal input port, the other input port is served as an add light signal input port, one output port of two output ports of the acousto-optic tunable filter is served as an output light signal output port, and the other output port is served as a split light signal output port;

the surface acoustic wave control signal source generates a surface acoustic wave control signal for adding/dropping a light signal; and

the control unit receives an information of the surface acoustic wave control signal from the surface acoustic wave control signal source through the remote transmission means, and supplies the surface acoustic wave control signal to the control port functioning as an add/drop control port of the acousto-optic tunable filter.

12. A remote control device of an acousto-optic tunable filter, as claimed in claim 11, wherein:

the remote control device further comprises a surface acoustic wave light control signal transmitting unit that outputs to convert the surface acoustic wave control signal for adding/dropping a light signal from the surface acoustic wave control signal source into a surface acoustic wave light control signal for adding/dropping a light signal;

the control unit contains a receiving unit that receives the surface acoustic wave light control signal for adding/dropping a light signal from the surface acoustic wave light control signal transmitting unit and converts the surface acoustic wave light control signal into the surface acoustic wave control signal for adding/dropping a light signal, and a driving unit that supplies the surface acoustic wave control signal for adding/dropping light signal received by the receiving unit to the add/drop control port of the acousto-optic tunable filter.

13. A remote control device of an acousto-optic tunable filter, as claimed in claim 11, wherein the acousto-optic tunable filter receives a light signal from a light signal transmit terminal through the input light signal input port thereof and outputs a light signal to a light signal receive terminal through the output light signal output port thereof, and the acousto-optic tunable filter receives a light signal from a branch terminal through the add light signal input port thereof and outputs a light signal to the branch terminal through the split light signal output port thereof;

the remote control device further comprises a surface acoustic wave light control signal transmitting unit that outputs to convert the surface acoustic wave control signal for adding/dropping a light signal from the surface acoustic wave control signal source into a surface acoustic wave light control signal for adding/dropping a light signal;

the surface acoustic wave control signal source and the surface acoustic wave light control signal transmitting unit are disposed in either the branch terminal or the light signal transmit terminal;

and the control unit contains a receiving unit that receives the surface acoustic wave light control signal for adding/dropping light signal from the surface acoustic wave light control signal transmitting unit and converts the surface acoustic wave light control signal into the surface acoustic wave control signal for adding/dropping a light signal, and a driving unit that supplies the surface acoustic wave control signal for adding/dropping a light signal received by the receiving unit to the add/drop control port of the acousto-optic tunable filter.

15. A remote control device of an acousto-optic tunable filter, as claimed in claim 14, wherein:

the remote control device further comprises surface acoustic wave light control signal transmitting units that output to convert the first and the second surface acoustic wave control signal from the surface acoustic wave control signal sources into a first and a second surface acoustic wave light control signal;

the control units contain receiving units that receive the first and the second surface acoustic wave light control signal from the surface acoustic wave light control signal transmitting units and convert the surface acoustic wave light control signals into the first and the second surface acoustic wave control signal, and driving units that supply the first and the second surface acoustic wave control signal received by the receiving units to the first and the second control port, respectively, of the first and second acousto-optic tunable filters.

16. A remote control device of an acousto-optic tunable filter, as claimed in claim 15, wherein:

the first and second surface acoustic wave control signals are combined into a common surface acoustic wave control signal to be shared by the first and second acousto-optic tunable filters;

the remote control device further comprises a surface acoustic wave light control signal transmitting unit that outputs to convert the common surface acoustic wave control signal from the surface acoustic wave control signal source into a surface acoustic wave light control signal;

the control unit contains a receiving unit that receives the surface acoustic wave light control signal from the surface acoustic wave light control signal transmitting unit and converts the surface acoustic wave light control signal into the common surface acoustic wave control signal, and a driving unit that supplies the common surface acoustic wave control signal received by the receiving unit to the first and second control ports of the first and second acousto-optic tunable filters.

17. A remote control device of an acousto-optic tunable filter, as claimed in claim 14, wherein, in order to make the first and second acousto-optic tunable filters function as a optical add/drop multiplexer:

one input ports of two pairs of two input ports of the first and second acousto-optic tunable filters are served as first and second input light signal input ports, the other input ports are served as first and second add light signal input ports, one output ports of two pairs of two output ports of the first and second acousto-optic tunable filters are served as first and second output light signal output ports, and the other output ports are served as first and second split light signal output ports, and

the first and the second acousto-optic tunable filter receive light signals from a first and a second light signal transmit receive terminal, respectively, through the first and the second input light signal input port thereof and output light signals to the first and the second light signal transmit receive terminal, respectively, through the first and the second output light signal output port thereof, and the first and the second acousto-optic tunable filter receive light signals from a branch terminal, respectively, through the first and the second add light signal input port thereof and output light signals to the branch terminal, respectively, through the first and the second split light signal output port thereof;

and the remote control device further comprises surface acoustic wave light control signal transmitting units that output to convert the first and second surface acoustic wave control signals for adding/dropping a light signal from the surface acoustic wave control signal sources into first and second surface acoustic wave light control signals for adding/dropping a light signal, and

the surface acoustic wave control signal sources and the surface acoustic wave light control signal transmitting units are disposed in either one of the first and second light signal transmit receive terminals and the branch terminal;

and the control units contain receiving units that receive the first and second surface acoustic wave light control signals for adding/dropping a light signal from the surface acoustic wave light control signal transmitting units and convert the surface acoustic wave light control signals into the first and second surface acoustic wave control signals for adding/dropping a light signal, and driving units that supply the first and second surface acoustic wave control signals for adding/dropping a light signal received by the receiving units to the first and second add/drop control ports of the acousto-optic tunable filters.

18. A remote control device of an acousto-optic tunable filter, as claimed in claim 14, wherein;

a wavelength demultiplexer to split first and second add light signals transmitted through a common optical transmission line is connected to the first and second add light signal input ports of the first and second acousto-optic tunable filters; and

a wavelength multiplexer to combine first and second split light signals from first and second split light signal output ports of the first and second acousto-optic tunable filters and transmit the combined light signal into the common optical transmission line is connected to the first and second split light signal output ports of the first and second acousto-optic tunable filters.

19. A remote control device of an acousto-optic tunable filter, as claimed in claim 18, wherein:

the first and second surface acoustic wave control signals are combined into a common surface acoustic wave control signal to be shared by the first and second acousto-optic tunable filters;

the remote control device further comprises a surface acoustic wave light control signal transmitting unit that outputs to convert the common surface acoustic wave control signal from the surface acoustic wave control signal source into a surface acoustic wave light control signal;

the control unit contains a receiving unit that receives the surface acoustic wave light control signal from the surface acoustic wave light control signal transmitting unit and converts the surface acoustic wave light control signal into the surface acoustic wave control signal, and a driving unit that supplies the surface acoustic wave control signal received by the receiving unit to the first and second control ports of the first and second acousto-optic tunable filters;

the receiving unit of the control unit receives the surface acoustic wave light control signal from the surface acoustic wave light control signal transmitting unit at the common optical transmission line in front of the demultiplexer, and converts the surface acoustic wave light control signal into the common surface acoustic wave control signal; and

the driving unit of the control unit supplies the common surface acoustic wave control signal received by the receiving unit to each of the first and second control ports of the first and second acousto-optic tunable filters.

14. A remote control device of an acousto-optic tunable filter, comprising:

a first acousto-optic tunable filter interpolated in an upward optical transmission line, capable of controlling an output state of an upward input light signal by being supplied with a first surface acoustic wave control signal through a first control port;

a second acousto-optic tunable filter interpolated in a downward optical transmission line, capable of controlling an output state of a downward input light signal by being supplied with a second surface acoustic wave control signal through a second control port;

surface acoustic wave control signal sources to generate the first and second surface acoustic wave control signals, which are provided at a remote place from the first and second acousto-optic tunable filters; and

control units that receive information of the first and second surface acoustic wave control signals from the surface acoustic wave control signal sources through remote transmission means, and supply the first and the second surface acoustic wave control signal to the first and the second control port, respectively, of the first and second acousto-optic tunable filters.

20. A remote control device of an acousto-optic tunable filter, comprising:

a first acousto-optic tunable filter interpolated in an upward optical transmission line, capable of controlling an output state of an upward input light signal by being supplied with a surface acoustic wave control signal through a first control port;

a second acousto-optic tunable filter interpolated in a downward optical transmission line, capable of controlling an output state of a downward input light signal by being supplied with the surface acoustic wave control signal through a second control port;

a third acousto-optic tunable filter interpolated in the downstream of the second acousto-optic tunable filter in the downward optical transmission line, capable of controlling an output state of the downward input light signal outputted from the second acousto-optic tunable filter by being supplied with the surface acoustic wave control signal through a third control port;

a surface acoustic wave control signal source to generate the surface acoustic wave control signal, which is provided at a remote place from the first, second, and third acousto-optic tunable filters; and

a control unit that receives an information of the surface acoustic wave control signal from the surface acoustic wave control signal source through remote transmission means, and supplies the surface acoustic wave control signal to the first, second, and third control ports of the first, second, and third acousto-optic tunable filters.

21. A remote control device of an acousto-optic tunable filter, as claimed in claim 20, wherein the remote control device further comprises:

a bypass to bypass the first acousto-optic tunable filter;

switching means to switch the transmission path of the upward input light signal into the first acousto-optic tunable filter or the bypass; and

a switching control unit to control a switching state of the switching means.

22. A remote control device of an acousto-optic tunable filter, as claimed in claim 20, wherein the remote control device further comprises:

a switching unit to connect the split light signal output port of the second acousto-optic tunable filter to the add light signal input port of the third acousto-optic tunable filter; and

a switching control unit to control a connection state of the split light signal output port and the add light signal input port.

24. An optical transmission system containing equalizers using acousto-optic tunable filters, as claimed in claim 23, wherein the surface acoustic wave control signal source is installed in the light signal transmit terminal.

26. An optical transmission system containing a optical add/drop multiplexer using an acousto-optic tunable filter, as claimed in claim 25, wherein the surface acoustic wave control signal source is installed in either one of the light signal transmit terminal and the branch terminal.

23. An optical transmission system containing equalizers using acousto-optic tunable filters, wherein:

plurality of equalizers are cascaded in the optical transmission line installed between a light signal transmit terminal and a light signal receive terminal, and the equalizers are comprised of the acousto-optic tunable filters capable of controlling output states of input light signals by being supplied with surface acoustic wave control signals through control ports;

the optical transmission system contains, at remote places from the acousto-optic tunable filters, surface acoustic wave control signal sources to generate the surface acoustic wave control signals and surface acoustic wave light control signal transmitting units that output to convert the surface acoustic wave control signals from the surface acoustic wave control signal sources into surface acoustic wave light control signals; and

each of the equalizers is provided with a control unit including a receiving unit that receives the surface acoustic wave light control signal from the surface acoustic wave light control signal transmitting unit through the optical transmission line and converts the surface acoustic wave light control signal into the surface acoustic wave control signal, and a driving unit that supplies the surface acoustic wave control signal received by the receiving unit to the control port of the acousto-optic tunable filter.

25. An optical transmission system containing a optical add/drop multiplexer using an acousto-optic tunable filter, wherein:

the optical add/drop multiplexer is connected through optical transmission lines between a light signal transmit terminal, a light signal receive terminal, and a branch terminal, and is comprised of the acousto-optic tunable filter capable of controlling an output state of an input light signal by being supplied with a surface acoustic wave control signal through a control port;

the optical transmission system contains, at a remote place from the acousto-optic tunable filter, a surface acoustic wave control signal source to generate the surface acoustic wave control signal and a surface acoustic wave light control signal transmitting unit that outputs to convert the surface acoustic wave control signal from the surface acoustic wave control signal source into a surface acoustic wave light control signal; and

the optical add/drop multiplexer is provided with a control unit including a receiving unit that receives the surface acoustic wave light control signal from the surface acoustic wave light control signal transmitting unit through the optical transmission line and converts the surface acoustic wave light control signal into the surface acoustic wave control signal, and a driving unit that supplies the surface acoustic wave control signal received by the receiving unit to the control port of the acousto-optic tunable filter.