Method of automatic adjustment of dither amplitude of MEMS mirror arrays
First Claim
1. A method for adjusting a dither amplitude of one or more MEMS mirrors in an optical switch having an input port, and an array of one or more MEMS mirrors that can be selectively optically coupled to one or more of N optical input/output (I/O) ports, where N is an integer greater than or equal to 3, the method comprising the steps of:
- aligning the one or more MEMS mirrors to achieve nominal peak coupling at each of the N collimators;
storing to a non-volatile memory digital-to-analog converter (DAC) settings for positioning each mirror in an open control loop as a function of the selected collimator; and
determining a dither amplitude DITHER(x) for one of the MEMS mirrors positioned to couple optical signals to an output port at a position x for using the stored DAC settings.
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Abstract
Methods for adjusting dither amplitude for MEMS mirrors in optical switches and optical switches employing such a method are disclosed. A dither amplitude of one or more MEMS mirrors may be adjusted in an optical switch having an input port, and an array of one or more MEMS mirrors that can be selectively optically coupled to one or more of N≧3 optical input/output (I/O) ports. The MEMS mirrors are aligned mirrors to achieve nominal peak coupling at each of the N collimators. Digital-to-analog (DAC) settings for positioning mirrors in an open control loop as a function of the selected collimator are stored to a non-volatile memory. The DAC settings are used to determine a dither amplitude DITHER(x) for one of the MEMS mirrors positioned to couple optical signals to an output port at a position x. The optical switch apparatus may comprise N≧3 optical input/output (I/O) ports, an array of one or more MEMS mirrors that can selectively reflect one or more spectral channels to one or more of the N ports, and a servo-control assembly in communication with said one or more of the MEMS mirrors. The servo control assembly includes memory containing digital-to-analog converter (DAC) settings for positioning each mirror in an open control loop as a function of a port position x. The servo control assembly is programmed to adjust dither amplitude of one or more of the MEMS mirrors using the stored DAC settings.
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Citations
19 Claims
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1. A method for adjusting a dither amplitude of one or more MEMS mirrors in an optical switch having an input port, and an array of one or more MEMS mirrors that can be selectively optically coupled to one or more of N optical input/output (I/O) ports, where N is an integer greater than or equal to 3, the method comprising the steps of:
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aligning the one or more MEMS mirrors to achieve nominal peak coupling at each of the N collimators;
storing to a non-volatile memory digital-to-analog converter (DAC) settings for positioning each mirror in an open control loop as a function of the selected collimator; and
determining a dither amplitude DITHER(x) for one of the MEMS mirrors positioned to couple optical signals to an output port at a position x for using the stored DAC settings. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A method for adjusting dither amplitude of one or more MEMS mirrors in an optical switch having an input port, and an array of one or more MEMS mirrors that can be selectively optically coupled to one or more of N optical input/output (I/O) ports, where N is an integer greater than or equal to 3, the method comprising the steps of:
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for a given one of the mirrors, determining N signal values Sc, wherein each signal value Sc corresponds to a signal applied to the given mirror to couple an optical signal between the input port and a different one of the N output ports;
fitting the N signal values to a polynomial of a parameter corresponding to a position of an output port;
determining a slope of the polynomial at a value corresponding to a given output port;
determining a dither amplitude based on the value of the slope.
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8. An optical switch apparatus, comprising:
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N optical input/output (I/O) ports, where N is an integer greater than or equal to 3;
and an array of one or more MEMS mirrors that can be selectively reflect one or more spectral channels to one or more of the N ports; and
a servo-control assembly in communication with said one or more of the MEMS mirrors, said servo-control assembly being adapted to control of said channel micromirrors and thereby maintaining a predetermined coupling of each reflected spectral channel into one of said output ports, wherein the servo control assembly includes memory containing digital-to-analog converter (DAC) settings for positioning each mirror in an open control loop as a function of a port position x, wherein the servo control assembly includes a processing unit programmed with a set of instructions for implementing a method of adjusting a dither amplitude of one or more of the MEMS mirrors, the set of instructions including an instruction for determining a dither amplitude DITHER(x) for one of the MEMS mirrors positioned to couple optical signals to an output port at a position x for using the stored DAC settings. - View Dependent Claims (9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19)
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Specification