Optical: systems and elements – Polarization without modulation – Depolarization
Reexamination Certificate
2006-12-26
2006-12-26
Mack, Ricky (Department: 2873)
Optical: systems and elements
Polarization without modulation
Depolarization
C359S506000, C359S490020, C359S256000
Reexamination Certificate
active
07154668
ABSTRACT:
The attenuation profile of an optical system, which defines the power variation as a function of wavelength is adjusted to alter the slope of its contour. The device is useful in a wavelength division modulation system to flatten the profile of an amplifier or the like that has a non uniform power variation with wavelength. The invention adjusts the slope by first providing an input light signal that has a known polarization state, e.g., processing the input into a known phase and amplitude relation between orthogonal components, such as plane polarized at a given alignment. The signal is then passed through a series of waveplates. The waveplates have different phase retardation and orientation resulting in wavelength dependent polarization change. According to an inventive aspect, by tuning the phase retardation of multiple tunable waveplates the desired wavelength dependent polarization changes over a useful wavelength range can be produced. At the downstream end of the signal path, a polarization discriminating element such as a polarizer or beam splitter, passes or blocks light energy as a function of polarization, thus converting the variation of polarization state into a variation of amplitude.
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Patel Jayantilal S.
Zhuang Zhizhong
Duane Morris LLP
Mack Ricky
Optellios, Inc.
Thomas Brandi
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