type of array

I would like to solve following task:
I have got a grid (nCellsY, nCellsZ). Each grid cell can contain no fiber, one fiber ore more fibers.
I know in which cell the fibers are.

I need to know the indices of the fibers which are in one cell.
For example a short list of fibers:

fiberInCellY = (/1,5,3,5,4,3,1/)
fiberInCellZ = (/1,4,6,1,2,5,1/)

I would like to get following:

Cell              Index of fiber      Index of fiber

GridFibers(1,1)   1                   7
GridFibers(5,1)   4
GridFibers(4,2)   5
GridFibers(5,4)   2

...and so on...

but with my following code it shows me no index:

PROGRAM run
IMPLICIT NONE
INTEGER, DIMENSION(7) :: fiberInCellY, fiberInCellZ
INTEGER i, j, k, nCellsY, nCellsZ


type :: indFibInCell
    integer, allocatable, dimension(:) :: ind
end type indFibInCell

type (indFibInCell), allocatable, dimension(:,:) :: Gridfibers

fiberInCellY = (/1,5,3,5,4,3,1/)
fiberInCellZ = (/1,4,6,1,2,5,1/)
nCellsY = 6
nCellsZ = 6

allocate(GridFibers(nCellsY,nCellsZ))

do j=1, nCellsZ
    do i=1, nCellsY
        do k=1, 7
            if (i == fiberInCellY(k) .and. j == fiberInCellZ(k)) then
                Gridfibers(i,j)%ind = k
                print *, "Gridfibers(",i, "," ,j, ")", Gridfibers(i,j)%ind
            end if
        end do
    end do
end do

END PROGRAM run