Optical transmitting apparatus, method of increasing the number of paths of the apparatus, and optical switch module for increasing the number of paths of the apparatus

• US 20060098981A1
• Filed: 03/29/2005
• Published: 05/11/2006
• Est. Priority Date: 11/10/2004
• Status: Active Grant

• Current Assignee: Fujitsu Limited
• Original Assignee: Fujitsu Limited
• Inventors: Miura, Akira, Hoshida, Takeshi, Ooi, Hiroki, Terahara, Takafumi
• Granted Patent: US 7,620,321 B2
• Time in Patent Office: Days
• US Class Current: 398/45
• CPC Class Codes: H04J 14/0209 Multi-stage arrangements, e.g. by cascading multiplexers or demultiplexers
• 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
• CPC Class Codes: H04J 14/0217 Multi-degree architectures, e.g. having a connection degree greater than two
• CPC Class Codes: H04Q 11/0005 Switch and router aspects
• CPC Class Codes: H04Q 2011/0009 using wavelength filters
• CPC Class Codes: H04Q 2011/0016 using wavelength multiplexing or demultiplexing
• CPC Class Codes: H04Q 2011/0024 using space switching
• CPC Class Codes: H04Q 2011/003 using switches based on microelectro-mechanical systems [MEMS]
• CPC Class Codes: H04Q 2011/0032 using static wavelength routers (e.g. arrayed waveguide grating router [AWGR] )

Abstract

An optical transmitting apparatus is configured such that K pieces of output ports of optical path switching units whose input port is connected to k-th input transmission path are connected to first to K-th output transmission paths except for the k-th output transmission path and to the k-th input port of a dropping unit, and the optical path switching units and the dropping unit outputs light of wavelength which is part or all of WDM light received from said input port from a specific output port, and can output light having a wavelength different from that of the light output from said specific output port from an output port different from said specific output port. Accordingly, while largely reducing the number of optical fiber patch cords necessary in an optical transmitting apparatus and largely reducing the number of spare ports, the flexible expansion of apparatus function can be realized.

Claims

1. An optical transmitting apparatus to which first to K-th (where K denotes an integer of 2 or larger) input transmission paths and first to K-th output transmission paths are connected and which has dropping means, comprising

K pieces of optical path switching means each having an input port connected to said k-th (where k denotes an integer from 1 to K) input transmission path, and K pieces of output ports,

wherein the dropping means has K pieces of input ports connected to said first to K-th optical path switching means, and an output port,

said K pieces of output ports of said optical path switching means whose input port is connected to said k-th input transmission path are connected to said first to K-th output transmission paths except for the k-th output transmission path and to the k-th input port of said dropping means, and

said optical path switching means and said dropping means output light of wavelength which is part or all of wavelength division multiplex light received from said input port from a specific output port, and can output light having a wavelength different from that of the light output from said specific output port from an output port different from said specific output port.

2. An optical transmitting apparatus to which first to K-th (where K denotes an integer of 2 or larger) input transmission paths and first to K-th output transmission paths are connected and which has D pieces (where D denotes a natural number) of dropping means, comprising:

K pieces of optical path switching means each having an input port connected to said k-th (where k denotes an integer from 1 to K) input transmission path, and K pieces of output ports; and

K pieces of drop light switching means each having an input port and D pieces of output ports connected to the first to said D-th dropping means,

wherein said K pieces of output ports of said optical path switching means whose input port is connected to said k-th input transmission path are connected to said first to K-th output transmission paths except for the k-th output transmission path and the input port of said dropping means, and

said optical path switching means and said dropping light switching means output light of wavelength which is part or all of wavelength division multiplex light received from said input port from a specific output port and can output light having wavelength different from that of the light output from said specific output port from an output port different from said specific output port.

3. An optical transmitting apparatus comprising:

optical path switching means having a plurality of input ports connected to a plurality of input optical transmission paths for transmitting wavelength division multiplex signal light and a plurality of output ports connected to a plurality of output optical transmission paths for transmitting wavelength division multiplex signal light, capable of selecting signal light of one or more wavelength included in the wavelength division multiplex signal light received from any of the input ports and outputting the selected signal light from any of the outports;

add wavelength output means which combines add signal light of a plurality of wavelengths to obtain combined signal light and selectively couples add signal light having one or more wavelengths included in the combined signal light, as signal light to be multiplexed to wavelength division multiplex signal light to any of the output optical transmission paths, to any of the output ports of the optical path switching means; and

drop wavelength output means which selectively receives and combines the signal light having one or more wavelengths included in the wavelength division multiplex signal light input to each of the input ports of the optical path switching means and selectively outputs signal light included in the combined signal light on a wavelength unit basis,

wherein the optical transmitting apparatus is an apparatus to which wavelength division multiplex signal light of the maximum N wavelengths (where N denotes an integer of 2 or larger) is input from each of K pieces (where K denotes an integer of 2 or larger) of input optical transmission paths and which outputs wavelength division multiplex signal light of the maximum N wavelengths to each of the K pieces of output optical transmission paths,

when the minimum integer of integers M satisfying the relation of M≧

I_add/N where wavelength of add signal light to be output to any of the output optical transmission paths is set as I_add and wavelength of drop signal light to be dropped from any of the input optical transmission paths is set as I_drop is M_add, and the minimum integer of integers M′

satisfying the relation of M′

≧

I_drop/N is M_drop,

the optical path switching means comprises K pieces of 1×

(K+M_drop−

1) wavelength selecting switches provided for the K pieces of input optical transmission paths and selectively outputting signal light of one or more arbitrary wavelengths out of the wavelength division multiplex signal light from any of the (K+M_drop-1) output ports at the minimum, and K pieces of (K+M_add−

1)-input 1-output multiplexers provided for the K pieces of output optical transmission paths and having (K+M_add-1) input ports at the minimum and one output port,

to one of the 1×

(K+M_drop−

1) wavelength selecting switches, one of the input ports of (K−

1) pieces of (K+M_add−

1)-input 1-output multiplexers provided for the (K−

1) pieces of output optical transmission paths different from the input optical transmission path for which the 1×

(K+M_drop−

1) wavelength selecting switch is provided is connected,

the add wavelength output means has M_add pieces of add wavelength multiplexing and selecting units each of which is connected to one of the input ports of the K pieces of (K+M_add−

1)-input 1-output multiplexers, multiplexes the add signal light of N wavelengths at the maximum, and selectively outputs add signal light of one or more arbitrary wavelengths to any of the K pieces of (K+M_add−

1)-input 1-output multiplexers, and

the drop wavelength output means has M_drop pieces of drop wavelength multiplexing and selecting units each of which is connected to one of the output ports of the K pieces of (K+M_drop−

1) wavelength selecting switches, multiplexes outputs of the K pieces of 1×

(K+M_drop−

1) wavelength selecting switches, and selectively outputs drop signal light having arbitrary wavelength.

4. The optical transmitting apparatus according to claim 3, wherein the add wavelength multiplexing and selecting unit comprises:

an add signal light multiplexer for multiplexing the add signal light; and

a 1×

K wavelength selecting switch connected to one of the input ports of each of the K pieces of (K+M_add−

1) -input 1-output multiplexer and selectively outputting signal light having one or more arbitrary wavelengths included in output light of the add signal light multiplexer to one of the input ports of each of the K pieces of (K+M_add−

1)-input 1-output multiplexers.

5. The optical transmitting apparatus according to claim 3, wherein the drop wavelength multiplexing and selecting unit comprises:

a drop signal light multiplexer connected to each of the output ports of the K pieces of 1×

(K+M_drop−

1) wavelength selecting switches and multiplexing outputs of the K pieces of 1×

(K+M_drop−

1) wavelength selecting switches; and

a wavelength selector for selectively outputting signal light having arbitrary wavelength included in output light of the drop signal light multiplexer.

6. The optical transmitting apparatus according to claim 4, wherein the drop wavelength multiplexing and selecting unit comprises:

a drop signal light multiplexer connected to each of the output ports of the K pieces of 1×

(K+M_drop−

1) wavelength selecting switches and multiplexing outputs of the K pieces of 1×

(K+M_drop−

1) wavelength selecting switches; and

a wavelength selector for selectively outputting signal light having arbitrary wavelength included in output light of the drop signal light multiplexer.

7. An optical transmitting apparatus comprising:

optical path switching means having a plurality of input ports connected to a plurality of input optical transmission paths for transmitting wavelength division multiplex signal light and a plurality of output ports connected to a plurality of output optical transmission paths for transmitting wavelength division multiplex signal light, capable of selecting signal light of one or more wavelengths included in the wavelength division multiplex signal light received from any of the input ports and outputting the selected wavelength signal light from any of the output ports;

add wavelength output means which combines add signal light having a plurality of wavelengths to obtain a combined signal light and selectively couples add signal light having one or more wavelengths included in the combined signal light, as signal light to be multiplexed to wavelength division multiplex signal light to any of the output optical transmission paths, to any of the output ports of the optical path switching means; and

drop wavelength output means which selectively receives and combines the signal light having one or more wavelengths included in the wavelength division multiplex signal light input to each of the input ports of the optical path switching means and selectively outputs signal light included in the combined signal light on a wavelength unit basis,

wherein the optical transmitting apparatus is an apparatus to which wavelength division multiplex signal light of the maximum N wavelengths (where N denotes an integer of 2 or larger) is input from each of K pieces of (where K denotes an integer of 2 or larger) input optical transmission paths and which outputs wavelength division multiplex signal light of the maximum N wavelengths to each of the K pieces of output optical transmission paths,

when the minimum integer of integers M satisfying the relation of M≧

I_add/N where wavelength of add signal light to be output to any of the output optical transmission paths is set as I_add and wavelength of drop signal light to be dropped from any of the input optical transmission paths is set as I_drop is M_add, and the minimum integer of integers M′

satisfying the relation of M≧

I_drop/N is M_drop,

the optical path switching means comprises K pieces of 1×

K wavelength selecting switches provided for the K pieces of input optical transmission paths and selectively outputting signal light of one or more arbitrary wavelengths out of the wavelength division multiplex signal light from any of K output ports as the minimum, and K pieces of K-input 1-output multiplexers provided for the K pieces of output optical transmission paths and having K input ports at the minimum and one output port,

to one 1×

K wavelength selecting switch, one of the input ports of (K−

1) pieces of K-input 1-output multiplexers provided for the (K−

1) pieces of output optical transmission paths different from the input optical transmission path for which the 1×

K wavelength selecting switch is provided is connected,

the add wavelength output means has M_add pieces of add wavelength multiplexing and selecting units each having K pieces of output ports at the minimum, multiplexing the add signal light of the N wavelengths at the maximum, and selectively outputting add signal light having arbitrary one or more wavelengths from the output ports, and K pieces of M_add-input 1-output multiplexers each having M_add pieces of input ports and one output port, each of the input ports of the M_add-input and 1-output multiplexers is connected to one of the output ports of the M_add pieces of add wavelength multiplexing and selecting units, and the output port of the M_add-input 1-output multiplexer is connected to one of the input ports of the K-input 1-output multiplexer, and

the drop wavelength output means has K pieces of 1×

M_drop wavelength selecting switches each of which is connected to one of the output ports of the 1×

K wavelength selecting switch and outputting signal light having one or more arbitrary wavelengths out of output light from the 1×

K wavelength selecting switch from any of the M_drop pieces of output ports at the minimum; and

M_drop pieces of drop wavelength multiplexing and selecting units each connected to one of output ports of the K pieces of 1×

M_drop wavelength selecting switches, multiplexing outputs of the K pieces of 1×

M_drop wavelength selecting switches, and selectively outputting drop signal light having arbitrary wavelength.

8. The optical transmitting apparatus according to claim 7, wherein the add wavelength multiplexing and selecting unit comprises:

an add wavelength multiplexer for multiplexing the add signal light; and

a 1×

K wavelength selecting switch connected to one of the input ports of each of the K pieces of the M_add-input 1-output multiplexers and selectively outputting signal light having one or more arbitrary wavelengths included in output light of the add wavelength multiplexer to one of the input ports of each of the K pieces of M_add-input 1-output multiplexers.

9. The optical transmitting apparatus according to claim 7, wherein the drop wavelength multiplexing and selecting unit comprises:

a K-input 1-output drop wavelength multiplexer for multiplexing outputs from one of the output ports of each of the K pieces of 1×

M_drop wavelength selecting switches; and

a wavelength selector for selectively outputting signal light having arbitrary wavelength included in output light of the drop signal light multiplexer.

10. The optical transmitting apparatus according to claim 8, wherein the drop wavelength multiplexing and selecting unit comprises:

a K-input 1-output drop wavelength multiplexer for multiplexing outputs from one of the output ports of each of the K pieces of 1×

M_drop wavelength selecting switches; and

a wavelength selector for selectively outputting signal light having arbitrary wavelength included in output light of the drop signal light multiplexer.

11. A method of adding a path for an optical transmitting apparatus, wherein the number of transmission paths is increased by connecting an optical switch module having wavelength selecting switches of the number required in accordance with the number of transmission paths to be increased to an optical transmitting apparatus having optical path switching means by using an idle port of the wavelength selecting switches in the optical path switching means, and the optical path switching means is connected to a plurality of transmission paths for transmitting wavelength division multiplex signal light and is constructed by a combination of a plurality of wavelength selecting switches to output signal light having any wavelength included in the wavelength division multiplex signal light from a transmission path to another transmission path.

12. The method of adding a path for an optical transmitting apparatus according to claim 11, wherein the wavelength selecting switch in the optical path switching means is preliminarily provided with an idle port for adding at least one path.

13. The method of adding a path for an optical transmitting apparatus according to claim 12, wherein the number of transmission paths is further increased by preliminarily providing the wavelength selecting switch in the optical switch module with at least one idle port for adding a path so as to prepare for further increase in the number of transmission paths, and connecting another optical switch module by using the idle port.

14. The method of adding a path for an optical transmitting apparatus according to claim 11, wherein the number of transmission paths is further increased by preliminarily providing the wavelength selecting switch in the optical switch module with at least one idle port for adding a path so as to prepare for further increase in the number of transmission paths, and connecting another optical switch module by using the idle port.

15. The method of adding a path for an optical transmitting apparatus according to claim 14, wherein the optical switch module has one or more 1-input k-output (where k denotes an integer of 2 or larger) wavelength selecting switches and one or more k-input 1-output wavelength selecting switch, the input port of said 1-input k-output wavelength selecting switch and the output port of said k-input 1-output wavelength selecting switch are connected to the idle port of the wavelength selecting switch in the optical wavelength selecting means or an add transmission path, and at least one of output ports of said 1-input k-output wavelength selecting switch and at least one of input ports of said k-input 1-output wavelength selecting switch are set as idle ports for connecting said another optical switch module.

16. The method of adding a path for an optical transmitting apparatus according to claim 11, wherein the optical switch module is provided with an optical amplifier for amplifying signal light sent via a plurality of wavelength selecting switches.

17. An optical transmitting apparatus having optical path switching means connected to a plurality of transmission paths for transmitting wavelength division multiplex signal light and constructed by combining a plurality of wavelength selecting switches to output signal light having any wavelength included in the wavelength division multiplex signal light from a transmission path to another transmission path,

wherein the wavelength selecting switch in the optical path switching means is provided with an idle port for connecting an optical switch module constructed by including wavelength selecting switches of the number required in accordance with the number of transmission paths to be added.

18. An optical switch module for adding a path for an optical transmitting apparatus having optical path switching means connected to a plurality of transmission paths for transmitting wavelength division multiplex signal light and constructed by combining a plurality of wavelength selecting switches to output signal light having any wavelength included in the wavelength division multiplex signal light from a transmission path to another transmission path, comprising

wavelength selecting switches of the number necessary in accordance with the number of transmission paths to be added,

wherein the wavelength selecting switches are connected idle ports of the wavelength selecting switches in the optical path switching means in the optical transmitting apparatus.

19. The optical switch module for adding a path to an optical transmitting apparatus according to claim 18, wherein the wavelength selecting switch in the optical switch module is provided with an idle port for adding a path so as to prepare for further increase in the number of transmission paths, and connecting another optical switch module by using the idle port.

20. The optical switch module for adding a path to an optical transmitting apparatus according to claim 19, comprising,

one or more 1-input k-output wavelength selecting switches (where k denotes an integer of 2 or larger) and k-input 1-output wavelength selecting switches as the wavelength selecting switch

in the optical switch module,

wherein the input port of said 1-input k-output wavelength selecting switch and the output port of said k-input 1-output wavelength selecting switch are connected to the idle port of the wavelength selecting switch in the optical wavelength selecting means in the optical transmitting apparatus or an add transmission path, and at least one of the output ports of said 1-input k-output wavelength selecting switch and at least one of the input ports of said k-input 1-output wavelength selecting switch are provided as idle ports for connecting said another optical switch module.