Aperiodic quasi-phasematching gratings for chirp adjustments and frequency conversion of ultra-short pulses

Year	Description
1997	Invention patented by Mark A. Arbore and Martin M. Fejer on March 25th, 1997. Abstract: An apparatus and method for simultaneous chirp adjustment and frequency conversion of an ultra-short input optical pulse A.sub.1 characterized by a center angular frequency .omega..sub.1,0 in a non-linear optical material with a quasi-phasematching (QPM) grating exhibiting an aperiodic pattern of regions D.sub.j constituting a grating. Passing the ultra-short input optical pulse A.sub.1 through the grating gives rise to a chirp-adjusted and frequency-converted output optical pulse A.sub.2. In the preferred embodiment the non-linear optical material is a Second Harmonic Generator (SHG) such that the output optical pulse A.sub.2 generated from the input optical pulse A.sub.1 is a chirp-adjusted second harmonic of said ultra-short input optical pulse A.sub.1. In the general case the method and apparatus use a transfer function D(.OMEGA.) derived from the equation: where A.sub.1.sup.2 (.OMEGA.) is the Fourier transform of the square of input optical pulse A.sub.1 and A.sub.2 (.OMEGA.) is the Fourier transform of output optical pulse A.sub.2, to engineer gratings for frequency-conversion and chirp-adjustment.
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Invention: Aperiodic quasi-phasematching gratings for chirp adjustments and frequency conversion of ultra-short pulses