Wavelength slicer for optical signal switching
AssigneeOplink Communications, Inc.
InventorsHongtao Hou, Qin Zhang
Life of this patent
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Abstract
A wavelength slicing apparatus and method includes two filters having passbands offset from each other and from a signal channel. The offset passbands enhance transmission where they overlap and reduce transmission where they do not overlap such that transmission of optical signals in a neighboring channel is suppressed. A third filter having a passband centered on the signal channel frequency may be included to enhance optical signal isolation. Wavelength slicing techniques may be used for channel isolation or passband flattening. Wavelength slicing can be incorporated into wavelength division multiplexing (WDM) optical switching to improve optical isolation between channels during routing, multiplexing and demultiplexing operations.
Claims27
A wavelength slicing apparatus, comprising:
- a) a first filter having a plurality of first periodic passbands characterized by a plurality of first frequency peaks offset from a plurality of frequency channels of an optical signal;
- and
- b) a second filter optically coupled to the first filter having a plurality of second periodic passbands characterized by a plurality of second frequency peaks at offset from the plurality of frequency channels and from the plurality of first frequency peaks;
- wherein the first periodic passbands and the second periodic passbands partially overlap with each other and contain the plurality of frequency channels.
An optical wavelength filtering method, comprising:
- a) transmitting an optical signal through a first filter having a plurality of first periodic passbands characterized by a plurality of first frequency peaks offset from a plurality of frequency channels of an optical signal;
- and
- b) transmitting the optical signal through a second filter optically coupled to the first filter having a plurality of second periodic passbands characterized by a plurality of second peaks offset from the plurality of frequency channels and from the plurality of first frequency peaks;
- wherein the first periodic passbands and the second periodic passbands partially overlap with each other and contain the plurality of frequency channels.
An optical switching apparatus, comprising:
- a) a birefringent walk-off device configured to spatially separate an input signal into first and second optical signals having mutually orthogonal polarizations,
- b) a first polarization rotator, optically coupled to the walk-off device configured to selectively rotate a polarization of at least one of the first and second optical signals;
- c) a wavelength slicer including
- i) a first filter having a plurality of first periodic passbands characterized by a plurality of first center frequencies offset from a plurality of frequency channels of an optical;
- and
- ii) a second filter having a plurality of second periodic passbands characterized by a plurality of second center frequencies offset from the plurality of first center frequencies and the plurality of frequency channels;
- wherein the first periodic passbands and the second periodic passbands partially overlap with each other and contain the plurality of frequency channels.
Dependencies are inferred from the claim text.