The present invention provides a wide-sense, non-blocking WDM
cross-connect that utilizes a relatively small number of wavelength
interchangers. The cross-connect of the present invention comprises
first, second and third fabrics and one or more wavelength interchangers
that interconnect the first and second fabrics. Demands that require a
change in wavelength are routed through the first fabric, through one or
more of the wavelength interchangers, and through the second fabric.
Demands that do not require a change in wavelength are only routed
through the third fabric. A routing algorithm is utilized to ensure that
any sequence of connection requests and withdrawals can be routed without
disturbing any currently routed requests.