System for selecting optical fiber reels from inventory to fill an order

An optical fiber inventory selection system selects optical fibers from inventory for use in a communication network. In one embodiment, the system includes a vendor computer system that executes code that performs a number of steps. Initially, the system accesses a plurality of optical parameters for each of a plurality of optical fiber reels that are located in inventory. Next, a customer order is received that includes customer requirements for at least a portion of the plurality of optical parameters and a total optical fiber length, and may include requirements for sets of reels, blocks of sets, and batches of blocks. Then, two optical parameters are selected from the plurality of optical parameters that are included in the customer requirements. Next, a number of the optical fiber reels are combined into optical fiber reel pairs that meet the customer requirements for the selected two optical parameters. Finally, an appropriate number of the optical fiber reels are selected to meet the customer requirements for the total optical fiber length of the set. After selecting reels to make sets to the necessary requirements, the system may be used to select sets to make blocks and to select blocks to make batches of blocks.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention is generally directed to the selection of optical fibers and, more specifically, to the selection of optical fiber reels from inventory to fill an order, or to the selection of optical fiber reels from inventory to fabricate a cable or set of cables with specified optical parameters.

2. Technical Background

When an optical fiber is produced, the optical fiber is generally placed on a reel for storage within a warehouse, prior to shipment to a customer. Before the optical fiber reel is stored in the warehouse, however, various optical parameters of the optical fiber reel are normally recorded. When a customer order is received for optical fibers, optical fiber reels are generally selected so that when the optical fiber reels are assembled into final cables (e.g., submarine cables) customer requirements on the optical specifications may be met at a constituent (i.e., optical fiber reel), set (a number of optical fiber reels that will be spliced end-to-end to form a continuous fiber transmission line), block (a cable including all of the multiple sets that make up a cable) and batch (multiple cables) levels. For example, a customer may place an order for 3 cable lengths of 400 km (batch), each of the 3 cables having 100 fiber lengths (block), and each fiber length consisting of a number of fibers spliced together (sets) to form a correct length fiber which will then be assembled with 99 other fiber sets to form each cable. However, because of the number of different customer requirements and their stringency, many optical fiber reels fail to individually meet all of the customer requirements. By judiciously selecting optical fiber reels for use in a set, block, and/or batch, optical specifications can be tightened, thus, increasing a guardband and reducing variability at the set, block and/or batch level. The selection of the fibers may be done to meet specified optical parameters to enable fabrication of a set/block/batch with specific parameters for a standardized application, rather than for a specific customized customer order.

The selection of optical fiber reels from inventory for use in a submarine application, to fill a customer order, has typically been accomplished by two methods. A first method has been to manually select optical fiber reels from a spreadsheet (which contains various optical parameters on each optical fiber reel), such that the selected optical fiber reels, when combined, meet the customer requirements. However, manually selecting optical fiber reels from a spreadsheet is labor intensive, time consuming, seldom optimizes the optical parameters of the combined optical fiber reels and generally fails to optimize the use of inventory.

Thus, what is needed is a system and method for selecting optical fiber reels from inventory that provides the desired performance characteristics and which eliminates manual selection of reels while efficiently using inventory.

SUMMARY OF THE INVENTION

The present invention is directed to a system and method for selecting optical fibers from inventory and pairing sets of optical fiber reels having a different value for at least one optical property, so that the combined average for that property for those reels is improved, with respect to a desired target value, over the individual values of that property for each reel. In this way, optical fiber reels can be paired into optimized pairs of reels which can then be used in a communication network.

In one embodiment, an optical fiber inventory selection system includes a vendor computer system that executes code that performs a number of steps. Initially, a customer order is received that includes customer requirements for at least a portion of the plurality of optical parameters and a total optical fiber length. Next, the system accesses a plurality of optical parameters for each of a plurality of optical fiber reels that are located in inventory. Then, at least one, and preferably two optical parameters are selected from the plurality of optical parameters that are included in the customer requirements. Next, a number of the optical fiber reels are combined into optical fiber reel pairs that meet the customer requirements for the selected optical parameters. Finally, an appropriate number of the optical fiber reels are selected to meet the customer requirements for the total optical fiber length.

Additional features and advantages of the invention will be set forth in the detailed description which follows and will be apparent to those skilled in the art from the description or recognized by practicing the invention as described in the description which follows together with the claims and appended drawings.

It is to be understood that the foregoing description is exemplary of the invention only and is intended to provide an overview for the understanding of the nature and character of the invention as it is defined by the claims. The accompanying drawings are included to provide a further understanding of the invention and are incorporated and constitute part of this specification. The drawings illustrate various features and embodiments of the invention which, together with their description, serve to explain the principals and operation of the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The present invention is directed to a system and method for selecting optical fibers from inventory for use in a communication network. The present invention may be implemented with the assistance of a fiber selection routine that works by balancing the selection of optical fiber reels. That is, an optical fiber reel from one part (e.g., a left-half) of a fiber property distribution is paired with an optical fiber reel from an opposite part (e.g., a right-half) of the fiber property distribution such that the combined optical parameter of the pair is generally centered. While a large data set generally has its average at the mean of the distribution, the present invention pairs and matches the optical fiber reels so as to generally accurately center a set consisting of, for example, relatively few reels (e.g., four to eight).

When a set of individual optical fiber reels is reduced to a smaller set of carefully chosen pairs, the distribution of pairs is both more accurately centered and has a smaller spread or standard deviation. That is, the mean is closer to the target mean and the standard deviation, ‘sigma’, is reduced. Alternatively, the distribution of one or both opticals can be maintained by pairing reels from the left half of the distribution with other reels from the left half of the distribution and pairing reels from the right half of the distribution with other reels from the right half of the distribution. In general, a variety of pairing schemes can be used in order to obtain the desired distribution of pairs.

Preferably, the fiber selection routine selects at least one, and preferably two optical parameters for which the lowest percentage of the available optical fiber reels in inventory meet the customer order requirements. Then, optical fiber reels, which fail to meet one or both of the two optical specifications, are combined into pairs such that a length weighted average of each of the pairs meets both of the selected optical specifications. The routine steps through a series of possible pair combinations and once all possible pairs are made, the routine randomly selects optical fiber reels until a customer length requirement (i.e., a total optical fiber length) is met. If there are multiple requirements (set, block, and batch) this process may be repeated for each level of requirements.

Turning toFIG. 1, an exemplary computer network100is depicted. The exemplary computer network100includes four computer systems108,110,112, and114that may communicate with a network server116, located within an intranet118(e.g., a manufacturer local area network (LAN) or metropolitan area network (MAN)). According to the present invention, the network server116implements code, which provides a user interface, which facilitates communication between the network server116and a user of one or more of the computer systems108–114. As shown inFIG. 1, the computer system108is coupled to an Internet service provider (ISPA)104, via, for example, a T1line and the computer system110is coupled to an Internet service provider (ISPB)106, via, for example, a cable modem. The Internet service providers ISPA104and ISPB106are coupled to a communication link102(e.g., a public switched telephone network (PSTN)), which forms part of the computer network. The link102may, however, take other forms, such as broadband cable, wireless, etc. As shown, the network server116, of the intranet118, is also coupled to ISPB106, via link115, which is, for example, a T1line. In this manner, the computer systems108and110can communicate with the network server116or computer systems112and114, via the network server116. Any of the computer systems108–114may represent a user (e.g., an external or internal customer) computer system that is in communication with the network server116, so as to provide a customer order, including customer requirements for at least a portion of a plurality of optical parameters and a total optical fiber length. Of course, more or less computers could be employed as desired, and only a single computer can be used, if desired, to carry out the invention. The requirements may be for a standardized application without a specific customer order, or may be in response to a specific customized customer order.

According to one preferred embodiment of the present invention, the network server (e.g., a vendor computer system)116implements code, which allows the network server116to communicate with the user computer system108or110, as well as other computer systems. The network server116also implements fiber selection code, which allows the network server116to perform a number of steps. Initially, the network server116receives a customer order that includes customer requirements for at least a portion of a plurality of optical parameters and a total optical fiber length for a communication network from a user via, for example, the user computer system108. Next, the code running on the network server116selects at least one, and preferably at least two optical parameters, from the plurality of optical parameters that are included in the customer requirements. Then, the code combines the optical fiber reels into a number of optical fiber reel pairs such that the reel pairs meet the customer requirements for the selected optical parameters. Finally, the code selects an appropriate number of the optical fiber reels to meet the customer requirements for the total optical fiber length.

The plurality of optical parameters may include an attenuation at a specific wavelength, an attenuation at a water peak, a maximum attenuation over a wavelength range, an attenuation with bending, a cable cutoff wavelength, a zero dispersion wavelength, a zero dispersion slope, a maximum dispersion over a wavelength range, a range of desired dispersion for a particular wavelength, or a polarization mode dispersion value. It should be appreciated that other optical parameters can also be utilized.

While the computer system108preferably accesses the network server116, via the Internet, it should be appreciated that the network server116may be locally accessed or operated by a user through the computer systems112or114(e.g., through a local area network (LAN)) or may be accessed by another computer system through a dial-up connection. Preferably, the network server116includes a database120(stored on a mass storage device) that stores information (e.g., optical specifications and lengths) on each of the optical fiber reels currently in inventory. However, it is contemplated that the computer system114may be a file server that communicates with the network server116and stores the information on the plurality of optical fiber reels in a database. Communication between the network server116and the computer systems108–114may also be facilitated by a plurality of web pages. The data for a ‘collection’ of fibers, a subset of the total available fiber in inventory, is pulled from the database. The ‘collection’ includes only reels meeting the individual (constituent) optical requirements, and typically is only a subset of the available reels.

FIGS. 2A and 2Bare exemplary graphs depicting a distribution of optical fiber reels indicating a deviation amount from a desired zero dispersion wavelength and a deviation amount from a desired zero dispersion slope for each of the optical fiber reels in the collection. The collection could be all or a portion of a particular fiber type that is in inventory. As shown inFIG. 2A, the deviation from desired zero dispersion wavelength is plotted along the abscissa and the deviation from desired zero dispersion slope is plotted along the ordinate. As shown, the grid is divided into nine cells numbered starting with the first cell being in the lower left hand corner and increasing as one goes clockwise around the center cell, which is cell number9. (see Table 1, below) As a general rule, there can be up to four levels of optical specifications; a first optical specification on the optical fiber reel (constituent), a second optical specification on a set of optical fiber reels, a third optical specification on a cable (block) and a fourth optical specification at a batch level. Typically, these specifications are tighter at each level. Thus, constituents have the broadest specifications and batches have the tightest specifications. This is shown in the exemplary graphFIG. 2A. Zero dispersion wavelength (scaled by the upper and lower spec limits for the individual reel, so that the center of the scaled spec range is 0.0 and the width of the scale spec range is 1.0) is plotted versus dispersion slope at the zero dispersion wavelength (similarly scaled). Each data point, indicated by a plus (+) sign, corresponds to an individual fiber reel. As shown inFIG. 2A, the individual optical fiber reels meet all the individual (i.e., constituent) requirements and do not display any failing optical fiber reels. However, on this scaled plot, the more preferred tighter specifications for the set level are also plotted, the scaled set specs being +/−0.1 for zero dispersion wavelength λ0and +/−0.2 for dispersion slope. Each set, which is to include a number of the optical fiber reels from inventory, is required to meet these tighter optical specifications (defined by the center cell, i.e., cell9).FIG. 2Billustrates the average amount of deviation from the optimum desired slope and zero dispersion wavelength, for a number of fibers that have been paired together in accordance with the invention. In particular,FIG. 2Billustrates the results that are achieved by combining fibers from cell1with cell5, cell2with cell6, cell3with cell7, and cell4with cell8. This embodiment optimizes two optical parameters at a time. Alternatively, a single optical parameter could also be optimized, or a plurality of optical parameters could be optimized one at a time. Remaining unpaired fibers are still indicated by a plus (+) sign, and the remainder of the data points illustrated are of paired fiber sets. As shown inFIG. 2B, in order for a set of reels to be acceptable, the zero dispersion wavelength of an optical fiber reel set must have a scaled value between −0.1 and +0.1, and the zero dispersion slope must have a scaled value between −0.2 and +0.2. It should be apparent from viewingFIG. 2Athat a random selection of optical fiber reels may not efficiently generate a set whose average opticals are in the center cell (i.e., cell9) of the grid. However, after pairing the optical fiber reels, as is shown inFIG. 2B, utilizing a fiber selection routine according to the present invention, the majority of paired sets lie in the center cell. It will be appreciated that building sets from these pairs can be done quickly and efficiently utilizing practically the entire inventory, as shown inFIG. 2B.

According to another embodiment of the present invention, even the relative few reels outside the center cell ofFIG. 2Bcan be utilized since they may be combined with pairs in the center cell. After having generated a number of pairs, as shown inFIG. 2B, a new nine cell plot can be generated for two additional optical requirements and pairs of pairs can be matched in sequence so that third and fourth opticals are centered for each group of fibers. It should be appreciated that according to the present invention, sets of ‘n’ reels that center ‘n’ opticals and use substantially all of the current inventory can be readily generated.

Accordingly, the present invention readily generates a set of fibers with centered opticals that effectively make use of a relatively broad distribution of optical fiber reels even when the requirements for a set of optical fiber reels are relatively stringent. As described above, this is accomplished by a computer program that matches optical fiber reels so that the optical parameters balance out. It should be appreciated that the two-dimensional graphs ofFIGS. 2A and 2Bcan be extended to three, four or more parameters. It should also be appreciated that grids with a different number of cells (e.g., sixteen cells) can be utilized to organize the ‘pairing’ of the data, or a hierarchical sequence of grids (e.g., 64, then 16 cells) can be used to quickly optimize pairs. Alternatively, a ‘best pair’ for a given optical fiber reel can be determined by using a “figure of merit” for the opticals after pairing, with a program searching a subset or an entire data set to determine an optimal pair. The choice of search algorithm depends on the relative importance of the speed of selection, tightening of the distribution, or handling of large inventory and the initial distribution of the opticals relative to the final requirements.

Turning toFIG. 3A, a fiber selection routine300, according to one embodiment of the present invention, is illustrated. In step302, the routine300is initialized at which point control transfers to step304, where the routine300accepts the customer or standardized requirements. It will be appreciated that the customer requirements may be locally input directly into a computer system running the routine300or may be input remotely, via a computer network. Then, in step306, the routine300preferably selects one or more (in this case, two) optical parameters for which the greatest number of optical fiber reels in inventory fail to meet the customer requirements. Next, in step308, the routine300causes optical fiber reels to be combined into optical reel pairs, that when combined have centered optical parameters. Then, in step310, the routine300selects a number of the optical fiber reels according to a total required optical fiber length. Finally, in step312, the routine300terminates.

Moving toFIG. 3B, a fiber selection routine350, according to another embodiment of the present invention, is illustrated. In step352, the routine350is initiated. Next, in step354, the routine350accepts the customer or standardized requirements. Then, in step356, the routine350selects at least one (in this case two) optical parameters. Next, in step358, the routine350combines the optical fiber reels into optical fiber reel pairs. Then, in step360, the routine350selects one or more (in this case two) different optical parameters. Next, in step362, the routine350combines the two optical fiber reel pairs into pairs of optical fiber reel pairs. Then, in step364, the routine350selects a number of the optical fiber reels according to a total required optical fiber length before terminating at step366.

General Fiber Selection Routine Implementetion

According to the present invention, optical fiber reel selection from inventory is preferably performed by a routine that selects a number of optical fiber reels, to fill a customer order. In the discussion below, the terms are defined as follows: ‘A’ signifies any given cell1–9; ‘B’ signifies any given cell1–9; ‘USL’ is an upper specification limit for the opticals; ‘LSL’ is a lower specification limit for the opticals; ‘optical1’ is the worst optical; ‘optical2’ is a second worst optical; ‘opt1’ is optical1; ‘opt2’ is optical2; ‘opt1LSL’ is the LSL for optical1; ‘opt1USL’ is the USL for optical1; ‘opt2LSL’ is the LSL for optical2; ‘opt2USL’ is the USL for optical2; ‘numcell1’ is the number of reels in cell1; ‘numcell2’ is the number of reels in cell2; ‘numcell3’ is the number of reels in cell3; ‘numcell4’ is the number of reels in cell4; ‘numcell5’ is the number of reels in cell5; ‘numcell6’ is the number of reels in cell6; ‘numcell7’ is the number of reels in cell7; ‘numcell8’ is the number of reels in cell8; ‘lenA’ is the length of a reel from cell A; ‘lenB’ is the length of a reel from cell B; ‘opt1A’ is the optical1for a reel from cell A; ‘opt2A’ is the optical2for a reel from cell A; ‘opt1B’ is the optical1for a reel from cell B; and ‘opt2B’ is the optical2for a reel from cell B.

Initially, the routine selects the two worst opticals (optical1and optical2), which correspond to the optical parameters with, for example, the least kilometers within the selected optical specification. Preferably, the selection is based on the most restrictive specification for each optical and can be at a set, block or batch level. Next, the routine selects the LSL and USL limits for a nine cell grid. For selected opticals with only a USL, the lower specification limit is preferably set to one of an extremely low number, zero for opticals that only have positive values, the LSL for the constituent reels or the lowest value of all reels in the data set. For selected opticals with only a LSL, the upper specification limit is preferably set to one of an extremely high number, the USL for the constituent reels or the highest value of all reels in the data set. Alternatively, the LSL and USL limits for the 9 cell grid can be set to any value to achieve the outcome desired by the user.

Each optical fiber reel is then assigned to a cell number of a nine cell grid, as shown below in Table 1, and the number of reels in each of the cells1through8is counted. A reel with an optical below the LSL for optical1is assigned to either cell1,2or3. A reel with an optical above the USL for optical1is assigned to either cell7,6or5. A reel with an optical between the LSL and the USL for optical1is assigned to either cell8,9or4. A reel with an optical below the LSL for optical2is assigned to either cell1,8or7. A reel with an optical above the USL for optical2is assigned to either cell3,4or5. A reel with an optical between the LSL and USL for optical2is assigned to either cell2,9or6.

In general, the routine assigns the reels to a particular cell (i.e., cell=1 through cell=9) and counts the reels in each cell (i.e., numcell1through numcell8) as follows:if opt1<opt1LSL AND opt2<opt2LSL then cell=1 and numcell=numcell1+1if opt1<opt1LSL AND opt2LSL<=opt2<=opt2USL then cell=2 and numcell2=numcell2+1if opt1<opt1LSL AND opt2>opt2USL then cell=3 and numcell3=numcell3+1if opt1LSL<=opt1<=opt1USL AND opt2>opt2USL then cell=4 and numcell4=numcell4+1if opt1>opt1USL AND opt2>opt2USL then cell=5 and numcell5=numcell5+1if opt1>opt1USL AND opt2LSL<=opt2<=opt2USL then cell=6 and numcell6=numcell6+1if opt1>opt1USL AND opt2<opt2LSL then cell=7 and numcell7=numcell7+1if opt1LSL<=opt1<=opt1USL AND opt2<opt2LSL then cell=8 and numcell8=numcell8+1if opt1LSL<=opt1<=opt1USL AND opt2LSL<=opt2<=opt2USL thencell=9

Pairs of two optical fiber reels are then formed such that the length weighted average of the two optical fiber reels falls within optical specifications for both selected optical parameters (i.e., the opticals for cell9). Preferably, the routine pairs reels from opposite corners (i.e., cells1and5; cells3and7); pairs reels from corners with reels from opposite middles (i.e., cells1and6; cells3and6; cells5and2; cells7and2; cells3and8; cells5and8; cells1and4; and cells7and4) paired in order of the cell pairs containing the largest number of reels; pairs reels from adjacent middle cells (i.e., cells4and6; cells6and8; cells2and8; and cells2and4) paired in order of the cell pairs containing the largest number of reels; pairs reels from opposite middles (cells4and8; and cells2and6).

Additional pairing schemes can be implemented if advantageous. Cell9single reels and non-cell9single reels can be combined to make pairs. Cell9pairs and non-cell9reels can be combined to make triplets. Multiple pairings can be made which result in quadruplets, etc. (cell9triplet combined with non-cell9reel). As a general rule, making cell9/non cell9pairs is advantageous for sets consisting of 2 reels and making triplets and higher is advantageous for sets consisting of many reels.

As shown below in Table 2, the routine preferably implements a pre-pair sorting method and a pair search method that sorts cell A optical*length from worst to best, sorts cell B optical*length from worst to best, makes one pass through cell A opticals looking for pairs, where cell A is the cell with the fewest reels and then makes ‘n’ pass through cell B opticals, where ‘n’ is the number of records in cell A. The pre-pair sorting is modified as appropriate for other grids. For example, a 2N×2Ngrid will match cell (I,J) with cell (N-I+1,N-J+1), the cell symmetrically opposite the ‘center’ of the grid.

The following code can be utilized to determine passing pairs:if{opt1LSL*(lenA+lenB)<=(opt1A*lenA+opt1B*lenB)<=opt1USL*(lenA+lenB) andopt2LSL*(lenA+lenB)<=(opt2A*lenA+opt2B*lenB)<=opt2USL*(lenA+lenB) and used in a pair=false}then{used in a pair=truefiberid=fiber id reel from cell A concatenated with fiber id reel from cell Blength=lenA+lenBopt1=(opt1A*lenA+opt1B*lenB)/(lenA+lenB)opt2=(opt2A*lenA+opt2B*lenB)/(lenA+lenB) cell=9numcellA=numcellA−1numcellB=numcellB−1}

Among other techniques, a length weighted average or a length weighted quadrature average (for polarization mode dispersion (PMD)) may be used. The routine then selects two cells to pair, sorts cells according to cell sort order and uses pair making logic to make pairs until no more pairs can be made.

For the case of two reel set size, pairs need to have all opticals within specification and meet the specified length requirement. However, in certain cases, it is contemplated that all opticals may not need to pass for each pair. This generally increases the number of outliers that can be used.

Pair making logic for sets composed of two reels can potentially be expanded as follows:if{opt1LSL*(lenA+lenB)<=(opt1A*lenA+opt1B*lenB)<=opt1USL*(lenA+lenB) andopt2LSL*(lenA+lenB)<=(opt2A*lenA+opt2B*lenB)<=opt2USL*(lenA+lenB) andopt3LSL*(lenA+lenB)<=(opt3A*lenA+opt3B*lenB)<=opt3USL*(lenA+lenB) andopt4LSL*(lenA+lenB)<=(opt4A*lenA+opt4B*lenB)<=opt4USL*(lenA+lenB) andetc. for all opticalsmin set length<=(lenA+lenB)<=max set length andused in a pair=false }

Pairs may also be based on the number of problem opticals. For example, if there were three problem opticals, the pair making logic can be:if{opt1LSL*(lenA+lenB)<=(opt1A*lenA+opt1B*lenB)<=opt1USL*(lenA+lenB) andopt2LSL*(lenA+lenB)<=(opt2A*lenA+opt2B*lenB)<=opt2USL*(lenA+lenB) andopt3LSL*(lenA+lenB)<=(opt3A*lenA+opt3B*lenB)<=opt3USL*(lenA+lenB) andused in a pair=false}

Then, the routine preferably randomly selects from cell9pairs, cell9single reels and non-cell9reels to make reel sets. Preferably, sets are formed with pairs and then cell9single reels and non-cell9reels. This can be accomplished by assigning a random number to each pair or reel and sorting the data using the random number so that a file contains randomly sorted pairs at the top and randomly sorted single reels at the bottom. Preferably, for each set the routine makes one pass through the file flagging selected reels. Once the set length size is reached or the end of the file is encountered, the routine returns to the top of the file to begin selection of the next set. However, using this approach sets can be assigned which never reach the set length requirement. Thus, the number of attempted sets needs to be greater than the number of required sets.

Assuming that minimum set size, maximum set size, and minimum reel length come from customer order requirements, the following code can be utilized to determine if a given length required is met.min reel length=max(customer min reel length, min reel length in data set)do i=1 to (number of sets to attempt)sum km in set=0do j=1 to (number records in data set)/* check to see if reel can be selected for a set */if {(sum km in set+length<min set size−min reel length) or(sum km in set+length>=min set size and sum km in set+length<=max set size)}andset number=not assignedthen/* add reel length to kms in set and assign set number */do(sum km in set)+lengthset number=iend/* if length requirement met for set—jump out of loop */if (sum km in set)>=min set size and (sum km in set)<=max set sizethen j=(number records in data set)+1endend

Preferably, the selection of the two worst opticals are based on the most restrictive of all specifications (at a set, block, or batch level).

In general, the process of combining sets into blocks and blocks into batches uses the same 9 cell grid approach as the process for combining reels into sets. Preferably, the same two opticals in the 9 cell grid are used for filling each level of the order. Alternatively, one can calculate the percent of sets outside the block limits to select the worst two opticals for the block 9 cell grid and calculate the percent of blocks outside the batch limits to select the worst two opticals for the batch 9 cell grid. To make blocks from sets, the 9 cell grid uses block LSL & USL and length weighted average opticals of passing sets. To make batches from blocks, the 9 cell grid uses batch LSL & USL and length weighted average opticals of passing blocks.

Additional logic is used to maximize the number of blocks and batches that can be made.

This logic addresses the issue of not having enough single sets after 9 cell grid pairing to make blocks consisting of an odd number of sets and likewise not having enough single blocks after 9 cell grid pairing to make batches consisting of an odd number of blocks.

For example, say an order requires 7 sets/block and the algorithm has generated 2 triples of sets, 20 pairs of sets, and 5 single sets. The maximum number of blocks that could be generated is 5 (1 block consisting of 2 triples of sets & 1 single set and 4 blocks consisting of 3 pairs of sets & 1 single set). The 8 remaining pairs of sets (16 sets) cannot be combined into blocks of 7 sets.

This issue is resolved by adding logic that creates a usable mix of triples, pairs, and singles to the 9 cell grid pair making process for blocks and batches. This is accomplished by adding counters to the code which keep a tally of the number of single sets, pairs of sets, triples of sets, etc. that have been generated. Each possible number of sets/block or blocks/batch has its own usable mix of triples, pairs, and singles. The algorithm stops pairing when the limit of the usable mix is reached. Using this logic in the above example the algorithm would stop when it has generated 2 triples of sets, 18 pairs of sets, and 9 single sets. These triples, pairs and singles could then be combined into 7 blocks (1 block consisting of 2 triples of sets & 1 single set and 6 blocks consisting of 3 pairs of sets & 1 single set). Only 2 single sets are unusable.

Alternatively, the algorithm could break pairs (and triples) up when needed to maximize the number of block or batches that can be made.

In another preferred embodiment of the invention, reels for different fiber types are selected to form an optimized combination of fiber reels which cab ne employed in a multi-fiber span in a telecommunications system. For example, so called dispersion managed systems can be comprised of a first fiber having positive dispersion at 1550 and positive slope, followed by a second fiber having negative dispersion and negative dispersion slope at 1550 nm. In one such embodiment, the fiber selection process may be broken down into three major components: (1) generating a selection of fiber sets having positive dispersion (+D) at a desired wavelength; (2) generating a selection of fiber sets having negative dispersion (−D) at the desired wavelength; and (3) matching appropriate +D fibers from the first set with appropriate −D fibers from the second set to arrive at a combination of +D and −D fibers which together form the desired residual dispersion and slope at a particular wavelength for the dispersion managed fiber combination which will be used in the telecommunications system. To generate the selection of +D and −D fiber sets, single reels of +D and −D fiber may be selected, or alternatively, each of the +D and −D fiber sets can be first optimized by combining two or more reels of a single (i.e., +D or −D) fiber type to from a combined pair length of such fibers which is optimized to be within a particular target range for one or more optical properties. Such +D and −D fiber sets can be generated, for example, using the 9 cell grid approach which was described hereinabove.

FIG. 4illustrates optical dispersion and dispersion slope distributions for a first set of hypothetical positive dispersion fibers and a second set of hypothetical negative dispersion fibers which are to be combined together to form a dispersion managed fiber span for use in a telecommunications system. The desired dispersion and dispersion slope specification range which is to occur when the two fibers are combined is defined by the box which is located at the intersection near the zero point on each axis. Each of the two different fiber types are manufactured to a target dispersion and slope value which is generally located in the center of the manufacturing distribution of each fiber. Consequently, in order to optimize the performance of the majority of fiber pairs which can be selected from the two manufacturing distributions and combined to form a dispersion managed pair, it is desirable to pair a +D fiber which has a slightly higher than target positive dispersion with a −D fiber that exhibits a slightly lower than target negative dispersion. In the embodiment illustrated, the target residual dispersion and slope box is shifted slightly to the negative side for a dispersion, as the desired residual dispersion is centered around −2.75 ps/nm-km . In this embodiment, the total desired length for the optical fiber span is 45 km and the dispersion of the negative dispersion fiber is approximately twice the magnitude of the dispersion of the positive dispersion fiber at 1550 nm. Consequently, by arranging the length of the respective fibers so that the length of the positive dispersion fiber is approximately twice that of the negative dispersion fiber, the resultant dispersion can be made to be zero, or slightly negative or slightly positive, as desired (or −2.75, as is the case with this example). As can be seen inFIG. 4, the manufacturing distribution of the negative dispersion fiber is larger than that of the positive dispersion fiber, as a result of the negative dispersion fiber being more difficult to manufacture. In order for a combination of +D and −D fibers to fall within the target specification range, as illustrated inFIG. 4, a line drawn between the two selected fibers must fall within, or cross through the desired target span specification range. In other words, pairs of +D and −D fiber are selected so that, for a given desired length combination, the resultant residual dispersion slope and dispersion values fall within the target box. However, in some instances, portions of the distribution of the existing −D fiber reels may not be readily combinable with existing +D fiber reels to arrive at a combined fiber that exhibits a combined dispersion and slope that falls within the target range, or more preferably in the center of the target range. For example, fibers from the upper left hand corner or lower right hand corner of the −D fiber distribution might not be combinable with the +D fibers illustrated to fall within the center of the target range. This problem can be averted, however, by first combining lengths of two or more reels of the −D fiber type which are at opposite ends of the product distribution (for example, by using the 9 cell product distribution combination approach described above), to from a combined pair length of −D fiber, that falls within the center (or closer to the center) of the desired −D product target, and the resultant combination −D fiber can then be combined with the +D fiber to form a dispersion managed pair that is optimized within the target region illustrated inFIG. 4. In this way, a first reel of fiber, for example which exhibits negative dispersion and negative dispersion slope at 1550 nm which is lower or higher than a desired target distribution for said first fiber, and a second reel of fiber of the same fiber which exhibits positive dispersion and dispersion slope at 1550 nm which is lower or higher than a desired target distribution for said second fiber may be combined so that a fiber having a dispersion or slope that is lower than the desired target for that fiber is combined with a fiber having a dispersion or slope which is higher than the desired target for that same type of fiber, and thereafter the resultant fiber could be combined with a positive dispersion fiber to form a dispersion managed pair.

Example 1 assumes that reels in cell3are to be combined with reels in cell7. Table 3, shown below, lists the relevant specifications for the reels in cell7and Table 4, shown below, lists the relevant specifications for cell3. Tables 3 and 4 include the following information: optical1is lambda (worst optical); optical2is slope (second worst optical); primary sort is lambda*length; secondary sort is slope*length; cell3—lambda*length sort is ascending, slope*length sort is descending; cell7—lambda*length sort is descending, slope*length sort is ascending; number of records in cell7is thirty-nine; and the number of records in cell3is one hundred. The routine makes one pass through cell7and thirty-nine passes through cell3looking for pairs. The results of the pair making are shown below in Table 5.

Accordingly, a system and method have been described that advantageously optimize utilization of optical fiber reels from inventory, when filling a customer order.

It will become apparent to those skilled in the art that various modifications to the preferred embodiment of the invention as described herein can be made without departing from the spirit or scope of the invention as defined by the appended claims.