Patent ID: 7280760
Filing Date: 2007-10-09
Classification: G02B,H04J

Abstract:
1. An upgradeable optical add/drop module, comprising: an optical input and an optical output; a first bandpass filter with a first pass band and optically coupled to the optical input, comprising a first reflection port and a first transmission port; a second bandpass filter with the first pass band and optically coupled to the optical output, comprising a second reflection port and a second transmission port; a third bandpass filter with a second pass band and optically coupled to the first reflection port, comprising a third transmission port and a third reflection port, wherein the third reflection port is configured to be connectable to a further bandpass filter in order to accommodate a plurality of additional channels; a fourth bandpass filter with the second pass band and optically coupled to the second reflection port, comprising a fourth transmission port and a fourth reflection port, wherein the fourth reflection port is configured to be connectable to a further bandpass filter in order to accommodate a plurality of additional channels; a first cascaded series of channel filter assemblies optically coupled to the first transmission port; a second cascaded series of channel filter assemblies optically coupled to the second transmission port; a third cascaded series of channel filter assemblies optically coupled to the third transmission port; and a fourth cascaded series of channel filter assemblies optically coupled to the fourth transmission port.