Method and apparatus for providing simultaneous channel power equalization and monitoring
OwnerXiang-Dong Caoinventor
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Abstract
A dynamic channel power equalization arrangement compensates for uneven channel powers of a wavelength multiplexed optical signal using diffractive gratings and semiconductor attenuator. A novel optical design is used to provide power equalization function and optical spectrum analyzer function in one single optical arrangement, as compared to the prior art in which there is only the power equalization function in such devices. This invention provides a simple cost-effective means for a complete solution for managing individual channel powers of wavelength-division multiplexed (WDM) signals.
Claims9
An optical arrangement for providing simultaneous dynamic gain equalization and channel measurement to a received distorted input signal comprising n wavelength multiplexed channels, the arrangement comprising:
- a pair of parallel diffractive gratings to separate each wavelength into parallel beam-let in space;
- a semiconductor attenuator that adjusts all channel power levels when a spatial voltage profile is provided and simultaneously measures all channel powers;
- a quarter-wave plate properly placed between the second grating and the semiconductor attenuator to eliminate polarization dependence of the optical arrangement;
- two collimators are used to collimate the signal from the input fiber to a beam with proper beam width that is optimal for the gratings;
- a 90-degree prism placed after the semiconductor attenuator is used to move the beam up or down and reflect the optical beam back at the same time so that the returning beam will be parallel to the input beam but shifted in height;
- an optical mirror used to separate the returned optical beam from the input or forward optical beam, and re-directs the optical beam to an output optical collimator.
Dependencies are inferred from the claim text.