Numerical analysis of nonlinear optical fiber couplers with a gaussian mode field distribution

✍ Scribed by Masaaki Imai; Toshiharu Adachi; Ken Takamatsu; Yoh Imai

• Publisher: John Wiley and Sons
• Year: 1996
• Tongue: English
• Weight: 546 KB
• Volume: 79
• Category: Article
• ISSN: 8756-663X
• DOI: 10.1002/ecjb.4420791205

✦ Synopsis

Nonlinear coupling characteristics taking account of evanescent field overlap were evaluated numerically by assuming a Gaussian field distribution for the mode field in nonlinear directional couplers (NLDC). The nonlinear coefficients Q3 to Qs were found to be Q3 = 3.7 x cm-', Q4 = Qs = 0 for the plane wave approximation used in Jensen's paper [l], with a core radius of 4 pm, a core spacing of 5 pm, a core refractive index of 1.455, and a nonlinear refractive index of 1.1 x lo-'* esu; and the wavelength of the incident light was 1.06 pm. On the other hand, in the case of the Gaussian field approximation, Q3 = 2.5 x lo-'* cm-I, Q4 = 2.2 x cm-l, and Q5 = 7.3 x cm-I were obtained, indicating that these values cannot be ignored. The full coupling period is increased by increasing the core spacing, and the full coupling period is decreased by using a longer wavelength. Further, from the dependence of nonlinear coupling characteristics on optical wavelength, it is confirmed that wavelength selective characteristics with a sharp bandpass filtering can be realized in NLDC.