Patent ID: 7910384
Filing Date: 2011-03-22
Classification: G02B,H01S

Abstract:
1. A method for producing a multiple wavelength reflector having a modulated grating for a desired reflection spectrum, comprising: a) determining a number of wavelengths that are to be reflected or an interval of wavelengths that is to be reflected by the reflector, b) calculating a preliminary grating with plural rulings that has a preliminary reflection spectrum r c) comparing the preliminary reflection spectrum r d) when step c) reveals a difference between the reflection spectrum r e) calculating a target function G(z) for a position z f) changing the rulings of the grating, depending on the values of the target function G(z) with respect to the target function's real part and the target function's imaginary part, by carrying out one or more of the following modifications: (i) adding one or several rulings to the grating where sufficient space is available, (ii) removing one or several rulings from the grating, and (iii) moving the position of one or several rulings of the grating, and g) repeating the steps c) to f) until the target function specifies that the grating reflects the number of wavelengths or the interval of wavelengths as specified in step a) to determine the number of rulings and the position of each ruling, h) etching the rulings determined in step g) in a grating material to produce the multiple wavelength reflector, wherein the rulings lie transverse to the longitudinal axis of the grating and each ruling has a refractive index that is higher or lower than an adjacent ruling.