Wavelength selection switches for optical application

An apparatus for transmitting radiation of multiple wavelengths, comprising:

• a first input channel carrying radiation of one or more wavelengths;
• a first output channel substantially aligned with the first input channel;
• a second input channel carrying radiation of a first wavelength to be added;
• a second output channel substantially aligned with the second input channel for receiving radiation of at least one wavelength that is to be dropped;
• and
• a switch member with at least one filter between the channels, wherein the switch member is movable between two different positions between the channels, wherein when the member is in a first position, the radiation carried by the first and second input channels impinges on a radiation transmissive portion of the member at a location away from the filter, and when the member is in a second position, the radiation carried by the first and second input channels impinges on the filter, said filter passing all of the wavelengths except for one wavelength in the radiation carried by the first input channel and reflecting radiation of such one wavelength and of the first wavelength.

An apparatus for transmitting radiation of multiple wavelengths, comprising:

• a first input channel carrying radiation of one or more wavelengths;
• a first output channel;
• a second input channel carrying radiation of a first wavelength to be added;
• a second output channel for receiving radiation of at least one wavelength that is to be dropped;
• a first and a second filter between the channels;
• a conveying channel between the two filters;
• and
• a switch member movable between two different positions between the channels, wherein when the member is in a first position, the radiation carried by the first and second input channels is transmitted respectively to the first and second output channels, and when the member is in a second position, said first filter passes radiation of one wavelength in the radiation carried by the first input channel to the second output channel and reflects the remaining wavelengths through the conveying channel to the second filter, said second filter reflecting the radiation of the first wavelength and radiation from the conveying channel to the first output channel.

An apparatus for transmitting radiation of multiple wavelengths, comprising:

• a first input channel carrying radiation of one or more wavelengths;
• a first output channel;
• a second input channel carrying radiation of a first wavelength to be added;
• a second output channel for receiving radiation of at least one wavelength that is to be dropped;
• at least one filter between the channels;
• and
• a switch member placed at two different positions between the channels so that when the member is in a first position, the radiation carried by the first input channel is received by the first output channel and the radiation of the first wavelength carried by the second input channel is received by the second output channel, and when the member is in a second position, at least some of the radiation carried by the first and second input channels impinges on the at least one filter, so that radiation of all but one of the wavelengths carried by the first input channel and the radiation of the first wavelength is received by the first output channel, and the radiation of the one wavelength carried by the first input channel not received by the first output channel is received by the second output channel.