Optical cross-connect system and optical transmission system

Abstract

Input/output fibers for the optical cross-connect system are classified into working fibers and protecting fibers. In a normal time (a state in which there occurs no failure), there turns out to be a one-to-one correspondence between a line terminal and a working fiber. Namely, connection property required for the switch matrix in the optical cross-connect system is not necessarily strictly non-blocking connections among all of the fibers. The connection property is a one-to-one connection relationship with the working fibers, and is a predetermined connection relationship with the protecting fibers at the time of a failure occurrence. Utilization thereof makes it possible to extremely downsize scale of the switch.

We claim:  
     
         1 . An optical cross-connect system provided among line terminals, working fibers and protecting fibers, and switching a fiber connected-with, said line terminals, comprising: 
 an input switching optical switch provided between an output port to the line terminals and a working input fiber port;    an output switching optical switch provided between an input port from the line terminals and a working output fiber port; and    a protecting path setting optical switch unit, the input of which are a 1-output from said output switching optical switch and an input from a protecting input fiber port, and the output of which are a 1-input to said input switching optical switch and an output to a protecting output fiber port.    
     
     
         2 . The optical cross-connect system as claimed in    claim 1   , wherein a rearrangable non-blocking optical switch matrix configuration is employed as a configuration of said protecting path setting optical switch unit.  
     
     
         3 . The optical cross-connect system as claimed in    claim 1   , wherein a blocking configuration or an incomplete matrix configuration which satisfies a predetermined protecting connection is employed as a configuration of said protecting path setting optical switch unit.  
     
     
         4 . The optical cross-connect system as claimed in    claim 1   , 
 wherein a means for switching a destination for each connected transmission-path between each working line terminal and each protecting line terminal corresponding to each other is added.    
     
     
         5 . The optical cross-connect system as claimed in    claim 2   , wherein a means for switching a destination for each connected transmission path between each working line terminal and each protecting line terminal corresponding to each other is added.  
     
     
         6 . The optical cross-connect system as claimed in    claim 3   , wherein a means for switching a destination for each connected transmission path between each working line terminal and each protecting line terminal corresponding to each other is added.  
     
     
         7 . The optical cross-connect system as claimed in    claim 4   , wherein the means for switching between the working line terminals and the protecting line terminals comprises an optical selection switch for selecting a working line terminal to be switched and a switching optical switch connected on the selection output side of said optical selection switch.  
     
     
         8 . The optical cross-connect system as claimed in    claim 5   , wherein the means for switching between the working line terminals and the protecting line terminals comprises: 
 an optical selection switch for selecting a working line terminal to be switched; and    a switching optical switch connected on the selection output side of said optical selection switch.    
     
     
         9 . The optical cross-connect system as claimed in    claim 6   , wherein the means for switching between the working line terminals and the protecting line terminals comprises an optical selection switch for selecting a working line terminal to be switched and a switching optical switch connected on the selection output side of said optical selection switch.  
     
     
         10 . The optical cross-connect system as claimed in    claim 4   , wherein the means for switching between the working line terminals and the protecting line terminals comprises an optical selection switch for selecting a working line terminal to be switched and an optical coupler connected on the selection output side of said optical selection switch.  
     
     
         11 . The optical cross-connect system as claimed in    claim 5   , wherein the means for switching between the working line terminals and the protecting line terminals comprises: 
 an optical selection switch for selecting a working line terminal to be switched and an optical coupler connected on the selection output side of said optical selection switch.    
     
     
         12 . The optical cross-connect system as claimed in    claim 6   , wherein the means for switching between the working line terminals and the protecting line terminals comprises: 
 an optical selection switch for selecting a working line terminal to be switched and an optical coupler connected on the selection output side of said optical selection switch.    
     
     
         13 . The optical cross-connect system as claimed in    claim 4   , wherein there is provided a means for connecting to a protecting transmission line an optical output which is derived from a protecting line terminal and branched by an optical selection switch.  
     
     
         14 . The optical cross-connect system as claimed in    claim 5   , wherein there is provided a means for connecting to a protecting transmission line an optical output which is derived from a protecting line terminal and branched by an optical selection switch.  
     
     
         15 . The optical cross-connect system as claimed in    claim 6   , wherein there is provided a means for connecting to a protecting transmission line an optical output which is derived from a protecting line terminal and branched by an optical selection switch.  
     
     
         16 . An optical transmission system, wherein the optical cross-connect system as claimed in    claim 1    is employed, and when a failure occurs on a line or a line terminal is troubled, an automatic switching to the protecting path or a protecting line terminal is performed.  
     
     
         17 . An optical transmission system, wherein the optical cross-connect system as claimed in    claim 4    is employed, and when a failure occurs on a line or a line terminal is troubled, an automatic switching to the protecting path or a protecting line terminal is performed.  
     
     
         18 . An optical cross-connect system wherein a switching optical switch is provided between an input/output port connected with line terminals and an input/output port connected with transmission paths corresponding to said line terminals, and a protecting path setting optical switch unit, through said switching optical switch, connects said line terminals with connection ports to protecting transmission paths.