Thompson, Michael Thomas (2006-08). Fast amplitude and delay measurement for characterization of optical devices. Master's Thesis. Thesis uri icon

abstract

  • A fast measurement technique based on the modulation phase-shift technique is developed to measure the wavelength-dependent magnitude and phase responses of optical devices. The measured phase response is in the form of group delay, which is used to determine the chromatic dispersion in the device under test by taking the derivative of the group delay with respect to optical wavelength. The measurement setup allows both step-tunable and sweeping laser sources. A modulation frequency of up to 2.7 GHz is accommodated. An alternate method for the phase measurement that overcomes non-linearities in the measurement setup is also presented. The speed of the measurement setup is limited by the sweeping speed of the laser source, which for the Agilent 81682A is 40 nm/sec. The magnitude accuracy is determined by taking a comparison to the commercially available Micron Finisar measurement system, where an error of 0.125 dB is noted. The phase accuracy of the measurement setup is tested by taking the Hilbert transform of the measured magnitude response of an Acetylene gas cell and comparing it to the integral of the measured group delay. The average deviation between the two methods is 0.1 radians. An Acetylene gas cell, fiber Bragg grating, and chirped Bragg grating are tested with the measurement setup and the Agilent 8168The characterization of the setup leads to the conclusion that the measurement setup developed in this paper is fast and accurate. The speed of the technique is on the order of microseconds for a single measurement and excels beyond the speed of the standard modulation phase-shift technique, which includes measurement times on the order of minutes. The accuracy of the technique is within 0.125 dB for magnitude measurements and 0.1 radians for phase measurements when compared to commercially available measurement systems.2A laser source at 40 nm/sec and the measurement plots are presented.
  • A fast measurement technique based on the modulation phase-shift technique is
    developed to measure the wavelength-dependent magnitude and phase responses of
    optical devices. The measured phase response is in the form of group delay, which is
    used to determine the chromatic dispersion in the device under test by taking the
    derivative of the group delay with respect to optical wavelength. The measurement
    setup allows both step-tunable and sweeping laser sources. A modulation frequency of
    up to 2.7 GHz is accommodated. An alternate method for the phase measurement that
    overcomes non-linearities in the measurement setup is also presented. The speed of the
    measurement setup is limited by the sweeping speed of the laser source, which for the
    Agilent 81682A is 40 nm/sec. The magnitude accuracy is determined by taking a
    comparison to the commercially available Micron Finisar measurement system, where
    an error of 0.125 dB is noted. The phase accuracy of the measurement setup is tested
    by taking the Hilbert transform of the measured magnitude response of an Acetylene
    gas cell and comparing it to the integral of the measured group delay. The average
    deviation between the two methods is 0.1 radians. An Acetylene gas cell, fiber Bragg
    grating, and chirped Bragg grating are tested with the measurement setup and the
    Agilent 8168The characterization of the setup leads to the conclusion that the measurement setup
    developed in this paper is fast and accurate. The speed of the technique is on the order
    of microseconds for a single measurement and excels beyond the speed of the standard
    modulation phase-shift technique, which includes measurement times on the order of
    minutes. The accuracy of the technique is within 0.125 dB for magnitude
    measurements and 0.1 radians for phase measurements when compared to
    commercially available measurement systems.2A laser source at 40 nm/sec and the measurement plots are presented.

publication date

  • August 2006