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Browse Prior Art Database

Wavelength Selective Optical Crossconnect

IP.com Disclosure Number: IPCOM000107511D
Original Publication Date: 1992-Mar-01
Included in the Prior Art Database: 2005-Mar-21
Document File: 3 page(s) / 154K

Publishing Venue

IBM

Related People

Georgiou, CJ: AUTHOR [+2]

Abstract

This article describes an efficient configurable crossconnect that exploits the useful bandwidth of optical fibers. The crossconnect supports all possible configurations (e.g., any-to-any, full or partial broadcast and many-to-one). It has a large throughput, but with substantially reduced hardware and relatively simple control compared to traditional space switches. (Image Omitted)

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 45% of the total text.

Wavelength Selective Optical Crossconnect

       This article describes an efficient configurable
crossconnect that exploits the useful bandwidth of optical fibers.
The crossconnect supports all possible configurations (e.g.,
any-to-any, full or partial broadcast and  many-to-one).  It has a
large throughput, but with substantially reduced hardware and
relatively simple control compared to traditional space switches.

                            (Image Omitted)

      The crossconnect is based on the vector-matrix multiplication
architecture which, together with Tunable Optical Filters (TOFs),
accomplishes an efficient way of selective switching. The vector-
matrix architecture supports many configurations (e.g., any-to-any,
full or partial broadcast and many-to-one) such that any desired
connection can  be  performed for each one of the wavelengths
involved, independently of other connections. The crucial device in
this architecture is the TOF which selects simultaneously the
appropriate wavelengths, thus performing the switching function.  One
possible candidate for the TOF is the Acousto-Optic Tunable Filter
(AOTF). Such AOTF was reported recently to have a capability to
select simultaneously several 10's of different wavelengths in the
range of 1200nm- 1600nm (1,2).

      An NxM crossconnect is composed of N 1xM optical splitters, M
1xN optical combiners and N.M TOFs connected altogether by N.M
single-mode fibers. The architecture is shown in the figure: each one
of the N input fibers is connected to an 1xM optical coupler which
splits the optical energy into M fibers connected to a column of
TOFs, such that input j broadcasts to all the M TOFs in column j.  On
the other side of the matrix, each one of the output fibers collects
the optical energy from N fibers connected to the corresponding row,
such that output i collects from row i. In this configuration we have
N.M independent filters, each one of them responsible for the
connection between each input-output pair.  Because the filter is
selective, it provides, besides the 2 spatial dimensions (M and N), a
third dimension K for switching wavelengths, where K stands for the
number of wavelengths that can be simultaneously selected by the
filter. The total number of wavelengths that can be supported
simultaneously in the crossconnect is, therefore, M.N.K.  Each input
fiber can carry up to K.M different wavelengths.  Different input
fibers do not carry necessarily the same wavelengths.  At the output,
each fiber can carry up to K  N different wavelengths. To clarify,
assume that we have a 4x4 crossconnect with 4 inputs and 4 outputs,
and the capability of the filter K=16 (meaning that 16 wavelengths
can be simultaneously  selected  from  the fiber).  In this case, we
have 4 input fibers, each one of them potentially carrying up to 64
wavelengths.  Therefore, the total number of wavelengths that can be
accommodated in the crossconnec...