| 摘要 |
Quasi-phasematching design to provide an approximation to a desired spectral amplitude response A(f) (102) is provided. An initial phase response ? (f) corresponding to A(f) (104) is generated. Preferably, d2 ? (f)/df2 is proportional to A2(f). Alternatively, ? (f) can be a polynomial in f. A function h(x) is computed such that h(x) and H(f) = A(f) exp(i ?(f) are a Fourier transform pair (106). A domain pattern function d(x) is computed by binarizing h(x) (108) (i.e., approximating h(x) with a constant-amplitude approximation). In some cases, the response provided by this d(x) is sufficiently close to A (f) that no further design work is necessary. In other cases, the design can be iteratively improved by modifying ? (f) responsive to a difference between the desired response A (f) and the response provided by domain pattern d(x). Various approaches for binarization are provided. The availability of multiple binarization approaches is helpful for making design trades.
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