US 6,888,976 B2 · Hitless tuning apparatus and methods for add/drop filters

Abstract

Switch devices for hitless tuning or reconfiguring an add or drop WDM filter. The input light is switched from the filter (where the desired channel is passed and the express channels are reflected) to a mirror where all channels are reflected. The switching is done in a continuous manner such that there is never an interruption in the channels reflected from the filter or mirror. While all channels are being reflected from the mirror, the filter is tuned to a different channel; or alternatively, is replaced by a filter which would drop a different channel. After the filter is tuned to the new channel, the input light is switched from the mirror back to the filter The switch may include a parallelogram prism or two sequential mirrors. The switch and the input beam are translated with respect to each other to switch the light between the filter and the mirror.

Claims16

Dependent claims

Apparatus for switching an input beam of light between a first location and a second location distinct from the first location comprising:

an input beam of light;
a parallelogram prism positioned to intercept the input beam;
the prism including a corner formed by a first side of the prism and an adjacent side of the prism;
a translating element for translating the prism and the light beam to selected positions relative to each other;
wherein in a first selected position the input beam intercepts the first side of the prism, in a second position, the beam intercepts the first side and the adjacent side at the corner, and in a third position the beam intercepts the adjacent side, such that all of the light in each position appears in the first location or the second location.

2 more elements

Apparatus for hitlessly tuning an optical add-drop filter comprising:

an input beam comprising channels of data;
a filter for selectively passing one or more channels of data and reflecting one or more channels of data;
a reflective surface for reflecting all of the channels of data;
and
a switch assembly for switching the input beam between the filter and the reflector, the switch assembly including
switch means for switching the input beam between the first and second locations, the switch means positioned to intercept the input beam;
and
means for translating the switch means and the light beam to selected positions relative to each other;
wherein in a first selected position all of the light appears in the first location, in a second position part of the light appears in the first location and part of the light appears in the second location and in a third position all of the light appears in the second location, and wherein none of the light appears between the first location and the second location in any of the positions.

6 more elements

Dependencies are inferred from the claim text.

Hitless tuning apparatus and methods for add/drop filters

Life of this patent

Hitless tuning apparatus and methods for add/drop filters

Life of this patent

Abstract

Claims16