光栅布局在大多数情况下是周期性
结构。OptiFDTD中有两种实现周期性布局的方法:PBG编辑器和VB脚本。本课将重点介绍以下功能:
K7_)!=DcX •使用VB脚本生成光栅(或周期性)布局。
4AF"+L •光栅布局
模拟和后处理分析
jpBE| Nm 布局layout
?94da4p 我们将模拟如图1所示的二维光栅布局。
=#+Z KD 图1.二维光栅布局
b]Z@zS<8 F48`1+ 用VB脚本定义一个2D光栅布局
JBWiTUk ".w*_1G7U 步骤:
?T4%"0 1 通过在
文件菜单中选择“New”,启动一个新项目。
(bBetX 2 在“Wafer Properties”对话框中设置以下
参数 Dri1A% Wafer Dimensions:
FG8bP Length (mm): 8.5
nt5 ~"8 Width (mm): 3.0
ueWG/`ig WO}JIExy 2D wafer properties:
\8t g7Sdq Wafer refractive index: Air
oW/&X5 3 点击 Profiles 与 Materials.
XhIgzaGVu `*N0 Lbl] 在“Materials”中加入以下
材料:
4Y)3<=kDG Name: N=1.5
3]c<7vdl Refractive index (Re:): 1.5
PN.=])7T ^|sQkufo Name: N=3.14
#lB[]2]N Refractive index (Re:): 3.14
;^
/9sLW?# ?Z14l0iZ%d 4.在“Profile”中定义以下轮廓:
L g%cVSz/C Name: ChannelPro_n=3.14
^lQ-w|7( 2D profile definition, Material: n=3.14
FS@SC`~( + S%+Ku Name: ChannelPro_n=1.5
,*%8*]<= 2D profile definition, Material: n=1.5
N[42al {fGi:b\[ 8 6.画出以下波导结构:
h 1Q7(8=Eg a. Linear waveguide 1
>ZNL
pJQ Label: linear1
\T[*|"RFZ Start Horizontal offset: 0.0
N.isvDk% Start vertical offset: -0.75
0[hl&7 Ab@ End Horizontal offset: 8.5
3~ZtAgih% End vertical offset: -0.75
6l> G>) Channel Thickness Tapering: Use Default
}'Z(J)Bg Width: 1.5
wvc?2~` Depth: 0.0
qi)(\ Profile: ChannelPro_n=1.5
B\("08x h]zx7zt-
b. Linear waveguide 2
IC{>q3 Label: linear2
(JM4W
"7' Start Horizontal offset: 0.5
i"-#1vy= Start vertical offset: 0.05
Gpgi@
Uf End Horizontal offset: 1.0
Lv_6Mf( End vertical offset: 0.05
10 p+e_@ Channel Thickness Tapering: Use Default
O Ov"h\, Width: 0.1
{`3;Pd` Depth: 0.0
{?j|]j Profile: ChannelPro_n=3.14
;pU LJ}rDb Ia(A&Za 7.加入水平平面波:
!
4s$93 Continuous Wave Wavelength: 0.63 General:
p(U'Ydl~ Input field Transverse: Rectangular
j$L<9(DoR X Position: 0.5
~ib#x~Db Direction: Negative Direction
0CDTj,eK Label: InputPlane1
zY#U ]Is 2D Transverse:
Sqb#U{E Center Position: 4.5
", |wG7N
K Half width: 5.0
C&;'Pw9H Titlitng Angle: 45
-bj1y2)n Effective Refractive Index: Local Amplitude: 1.0
@*_K#3 图2.波导结构(未设置周期)
JEP"2M N, [t6)M~&e:_ 8.单击“Layout Script”快捷工具栏或选择
仿真菜单下的“Generate Layout Script…”。这一步将把布局对象转换为VB脚本代码。
!~mN"+u& 将Linear2代码段修改如下:
Lc.7:r Dim Linear2
K]7@%cS for m=1 to 8
J,q: Set Linear2 = WGMgr.CreateObj ( "WGLinear", "Linear2"+Cstr(m) )
fx}R7GN2 Linear2.SetPosition 0.5+(m-1)*1.0, 0.05, 1+(m-1)*1.0, 0.05
_>aesp% Linear2.SetAttr "WidthExpr", "0.1"
JN8k x;@ Linear2.SetAttr "Depth", "0"
zcNV<tx Linear2.SetAttr "StartThickness", "0.000000"
\J13rL{< Linear2.SetAttr "EndThickness", "0.000000"
=9)ypI-2 Linear2.SetProfileName "ChannelPro_n=3.14"
%r>vZ/>a Linear2.SetDefaultThicknessTaperMode True
.Ftml' ! N7M^ 点击“Test Script”快捷工具栏运行修改后的VB脚本代码。生成光栅布局,布局如图3所示。
>kB?C!\ 图3.光栅布局通过VB脚本生成
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