Method and apparatus for providing gain equalization to an optical signal in an optical communication system

An optical amplifier system for amplifying with a prescribed gain at least one channel wavelength of a WDM optical signal, said optical amplifier arrangement comprising:

• an optical amplifier having an input port and an output port;
• a dynamic gain adjuster, said dynamic gain adjuster including:
• at least one input port for receiving the WDM optical signal and at least one output port, said output port of the dynamic gain adjuster being optically coupled to the input port of the optical amplifier;
• a plurality of wavelength selective elements that each select a channel wavelength from among the channel wavelengths received at the input port of the dynamic gain adjuster;
• a plurality of optical elements respectively associated with said plurality of wavelength selective elements, each of said optical elements directing one of the selected channel wavelengths selected by the associated wavelength selective element to said output port of the dynamic gain adjuster with a selectively variable degree of attenuation and independently of all other channel wavelengths;
• and
• a controller for adjusting a configuration of at least one of the optical elements to provide the channel wavelength directed by the optical element with the selectively variable degree of attenuation to achieve the prescribed gain at the output port of the optical amplifier.

A WDM optical communication system, comprising:

• a plurality of network nodes, each of said nodes including an optical switch;
• at least one optical communication link interconnecting said nodes;
• at least one gain adjustable optical amplifier arrangement located along the communication link, said gain adjustable optical amplifier arrangement including:
• an optical amplifier having an input port and an output port;
• a dynamic gain adjuster, said dynamic gain adjuster including:
• at least one input port for receiving the WDM optical signal and at least one output port, said output port of the dynamic gain adjuster being optically coupled to the input port of the optical amplifier;
• a plurality of wavelength selective elements that each select a channel wavelength from among the channel wavelengths received at the input port of the dynamic gain adjuster;
• a plurality of optical elements respectively associated with said plurality of wavelength selective elements, each of said optical elements directing one of the selected channel wavelengths selected by the associated wavelength selective element to said output port of the dynamic gain adjuster with a selectively variable degree of attenuation and independently of all other channel wavelengths;
• and
• a controller for adjusting a configuration of at least one of the optical elements to provide the channel wavelength directed by the optical element with the selectively variable degree of attenuation to achieve the prescribed gain at the output port of the optical amplifier.

An optical amplifier system for amplifying with a prescribed gain at least one channel wavelength of a WDM optical signal, said optical amplifier arrangement comprising:

• an optical amplifier having an input port and an output port;
• a dynamic gain adjuster, said dynamic gain adjuster including:
• at least one input port for receiving the WDM optical signal and at least one output port, said input port of the dynamic gain adjuster being optically coupled to the output port of the optical amplifier;
• a plurality of wavelength selective elements that each select a channel wavelength from among the channel wavelengths received at the input port of the dynamic gain adjuster;
• a plurality of optical elements respectively associated with said plurality of wavelength selective elements, each of said optical elements directing one of the selected channel wavelengths selected by the associated wavelength selective element to said output port of the dynamic gain adjuster with a selectively variable degree of attenuation and independently of all other channel wavelengths;
• and
• a controller for adjusting a configuration of at least one of the optical elements to provide the channel wavelength directed by the optical element with the selectively variable degree of attenuation to achieve the prescribed gain at the output port of the dynamic gain adjuster.

A method for directing at least first and second wavelength components of a WDM signal that includes a plurality of wavelength components from an input port to selected ones of a plurality of output ports, said method comprising the steps of:

• (a) demultiplexing the first wavelength component from the WDM signal;
• (b) directing the first wavelength component to a given output port while selectively attenuating the first wavelength component;
• (c) demultiplexing the second wavelength component from the WDM signal;
• and
• (d) directing the second wavelength component to one of the output ports selected independently from the given output port to which the first wavelength component is directed