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US 6,487,336 B1Granted
WDM channel equalization and control
AssigneeGeneral Photonics Corporation
InventorXiaotian Steve Yao
Life of this patent
Estimating the term…
Abstract
Devices that couple variable attenuators to a single WDM multiplexer to individually adjust and control the power levels of different WDM channels, e.g., substantially equalizing the power levels of the channels. Optical reflection and in-fiber variable attenuators are implemented to simplify the device structure and reduce cost.
Claims29
A device, comprising:
- an input optical terminal to transmit a plurality of input optical signals at different wavelengths;
- an optical multiplexer coupled to said input optical terminal and adapted to have a plurality of output optical terminals to separate said input optical signals at different wavelengths into said output optical terminals, respectively;
- a plurality of variable attenuators respectively coupled in said output optical terminals to respectively attenuate said optical signals in response to respective control signals so as to produce first attenuated signals;
- and
- an optical reflector coupled to said output optical terminals to receive and reflect said first attenuated signals back to said variable attenuators which generate second attenuated signals respectively traveling in said output terminals towards said optical multiplexer, wherein said optical multiplexer combines said second attenuated signals into said input optical terminal as output signals.
2 more elements
A method for controlling signal strengths of different WDM channels, comprising:
- causing WDM channels in an input fiber to be coupled into a WDM multiplexer which separates said WDM channels;
- causing separated WDM channels to be individually attenuated by independent variable attenuators;
- causing separated WDM channels to be reflected back to said variable attenuators to undergo attenuation for a second time;
- and
- causing reflected WDM channels to be combined by said WDM multiplexer into said input fiber as output signals.
2 more elements
A device, comprising:
- an input optical terminal to transmit a plurality of input optical signals at different wavelengths;
- an optical multiplexer coupled to said input optical terminal and adapted to have a plurality of output optical terminals to separate said input optical signals at different wavelengths into said output optical terminals, respectively;
- a plurality of variable attenuators respectively coupled in said output optical terminals to respectively attenuate said optical signals in response to respective control signals so as to produce first attenuated signals;
- means for causing a polarization rotation based on Faraday rotation in each of said first attenuated signals;
- and
- means for reflecting each of said first attenuated signals back to said means for causing Faraday rotation and to a respective variable attenuator to generate second attenuated signals respectively traveling in said output terminals towards said optical multiplexer, wherein said optical multiplexer combines said second attenuated signals into said input optical terminal as output signals.
3 more elements
Dependencies are inferred from the claim text.