Wavelength power equalization by attenuation in an optical switch
View Patent ↗A method for equalizing optical signal power in a group of optical signals transmitted through an optical switch in an optical transmission system. In one embodiment a group of optical signals is input into an optical switch having at least one movable mirror array with a plurality of reflectors formed thereon, the optical beam being directed onto a selected at least one reflector and wherein attenuating the optical beam is accomplished by controllably detuning at least one of the selected at least one reflector to attenuate the optical beam.
1. A fiber optic switching device enabling the switching of optical signals and the selective attenuation of optical signals, the device comprising:
an input fiber array;
an output fiber array;
an optical switch that includes at least one reflector array configured such that a light beam input into the switch from the input fiber array can be reflected by the at least one reflector array into a desired output fiber in the output fiber array as an output beam and configured so that adjustments to the at least one reflector array selectively attenuate the optical power of the light beam until output beam attains a desired optical power level;
a control element that facilitates switching of the light beam from the input fiber array to the desired output fiber and facilitates the selective attenuation of output beam until it attains a desired optical power level; and
a detector for measuring the optical power of the cutout beam and outputting an associated signal that is received by the control element which uses the signal to determine the amount of attenuation required in the output beam so that it can attain the desired optical power level.
2. The fiber optic switching device of claim 1 wherein the input fiber array and the output fiber array comprises a single fiber array.
3. The fiber optic switching device of claim 1 wherein the at least one reflector array selectively attenuates the optical power of the tight beam by detuning at least one of the reflectors of the at least one reflector array until the output beam attains a desired optical power level.
4. The fiber optic switching device of claim 3 wherein the detuning of the at least one of the reflectors attenuates the optical power of said output beam by sub-optimally coupling the output beam to an output fiber of the output fiber array.
5. The fiber optic switching device of claim 1 wherein the device is configured such that optical signals input by the input fiber array into the optical switch are selectively attenuated by the optical switch so that a more uniform power distribution is achieved among the optical signals.
6. The fiber optic switching device of claim 5 wherein the detector comprises a monitor element for monitoring the optical power of the optical signals; and
wherein the control element includes circuitry for determining the optical power of the weakest signal of the optical signals, thereby defining a baseline optical power level, wherein the circuitry implements a user selected power margin in combination with the baseline optical power level to define a user selected power range, and
wherein the circuitry selectively attenuates the optical power of optical signals that fall outside the user selected power range such that the signal power of each optical signal falls within the user selected power range.
7. The fiber optic switching device of claim 1 wherein the control element is configured to facilitate output beam attenuation using dithering to obtain selective attenuation of the output beam to obtain the desired optical power level.