Optical access network and its design method

1 . An optical access network that connects a communication station building and an optical termination position by optical cables, the optical access network comprising:

a plurality of optical cable loops, in which the optical cables are connected in a loop shape, wherein:

the optical cable loops are connected to each other;

the optical cable loops connected to each other have two connection points laid on a common route; and

an optical cable, laid on the common route to the other optical cable loops of the optical cable loops, is composed of an integrated loop cable obtained by integrating a plurality of optical cable loops.

2 . A method for designing an optical access network, the method comprising:

disposing a plurality of optical cable loops, in which optical cables are connected in a loop shape, between a communication station building and an optical termination position; and

connecting the optical cable loops to each other, wherein each of the optical cable loops has a length that is a single failure section length making a failure rate or the number of failure in times (FITs) less than a determined value based on an optical cable type or a construction environment.

3 . The method for designing an optical access network according to claim 2 , further comprising:

providing, on a common route, two connection points between the optical cable loops, in a section where the plurality of optical cable loops are laid on the common route; and

reducing the number of cores of at least one of two or more cables laid on the common route so that the same probability of increase is achieved, per fixed width of demand fluctuation, as that of the optical cable loops not laid on the common route.

4 . The method for designing an optical access network according to claim 2 , further comprising:

providing, on a common route, two connection points between the optical cable loops, in a section where the plurality of optical cable loops are laid on the common route; and

reducing the number of cores of two or more cables laid on the common route so that the same probability of increase is achieved, per fixed width of demand fluctuation, as that of state prior to integration.

5 . A method for designing an optical access network comprising:

disposing a plurality of optical cable loops, in which optical cables are connected in a loop shape, between a communication station building and an optical termination position; and

connecting the optical cable loops to each other, including:

providing, on a common route, two connection points between the optical cable loops, in a section where the plurality of optical cable loops are laid on the common route; and

widening a distance between the two connection points provided on the common route, within an allowable range on the common route.

6 . The method for designing an optical access network according to claim 5 , further comprising:

providing, on a common route, two connection points between the optical cable loops, in a section where the plurality of optical cable loops are laid on the common route; and

reducing the number of cores of at least one of two or more cables laid on the common route so that the same probability of increase is achieved, per fixed width of demand fluctuation, as that of the optical cable loops not laid on the common route.

7 . The method for designing an optical access network according to claim 5 , further comprising:

providing, on a common route, two connection points between the optical cable loops, in a section where the plurality of optical cable loops are laid on the common route; and

reducing the number of cores of two or more cables laid on the common route so that the same probability of increase is achieved, per fixed width of demand fluctuation, as that of state prior to integration.