Node for an optical network

A node for an optical network, the node comprising:

• an output to transmit to an optical network a first optical signal comprising a first wavelength component;
• an input to receive, from the optical network, light comprising plural wavelength components;
• and
• an optical interface optically connected to the input and the output, the first optical interface being to receive a removable optical wavelength selective filter arranged to extract the first wavelength component of the plural wavelength components from the light, thereby providing an optical signal comprising the first wavelength component and a second optical signal comprising a remainder of the plural wavelength components.

An optical network comprising plural nodes, each of the plural nodes being arranged to transmit an optical signal at a distinct wavelength, wherein a node of the plural nodes is arranged to:

• transmit a first optical signal comprising a first wavelength component;
• receive light comprising plural wavelength components including the first wavelength component;
• extract the first wavelength component from the light, thereby providing a second optical signal comprising a remainder of the plural wavelength components;
• and
• transmit the second optical signal.

A method of operating a node, wherein the node comprises:

• an input to receive from an optical network light comprising plural wavelength components;
• an optical wavelength selective filter, optically connected to the input, to extract a first wavelength component of the plural wavelength components from the light, thereby providing a first optical signal comprising the first wavelength component and a second optical signal comprising a remainder of the plural wavelength components;
• a first output optically connected to the optical wavelength selective filter to receive a first portion of the second optical signal for transmission to a light detector;
• and
• a second output optically connected to optical wavelength selective filter to receive a second portion of the second optical signal for transmission to the optical network,
• wherein the method comprises:
• transmitting an optical signal comprising the first wavelength component from the node;
• receiving the light comprising plural wavelength components including the first wavelength component at the node;
• and
• extracting the first wavelength component from the light at the node, thereby providing the second optical signal comprising the remainder of the plural wavelength components.