Finding the modes of ridged SiN waveguides on SiO2 and Si
"Boissier, Sebastien B" <[email protected]> Fri, 20 Nov 2015 15:15:49 +0000
| Newsgroups | gmane.comp.science.photonic-bands |
|---|---|
| Message-ID | <[email protected]> |
--===============4335723934992296031== Content-Language: en-US Content-Type: multipart/alternative; boundary="_000_6D86430ADF9448159F408D6677895727imperialacuk_" --_000_6D86430ADF9448159F408D6677895727imperialacuk_ Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable Dear Steven and MPB's users, I am attempting to find the mode structure of ridged SiN (n ~ 2) waveguides= which live on a layer of SiO2 ( ~ 2 um and n ~ 1.45) and with a layer of S= i (n ~ 3.5) underneath. The surrounding environment is air. I already know the frequency at which I want to solve the modes therefore I= am using the find-k function. My problem is that the algorithm always seem to find modes which are locali= sed in the layer of Si and I can not find those which are localised in the = SiN waveguide itself. Is there any way I can modify my control file (see bellow) to find only the= modes of interest? Is this an issue because of the enforced periodicity of= the solutions? Thank you for your held and time. Sebastien ; Define the simulation space (a =3D 1um) (define s_y 10) (define s_z 10) (set! geometry-lattice (make lattice (size no-size s_y s_z))) (set! resolution 32) ; Not a periodic structure (set! ensure-periodicity #f) ; Define dielectric parameters (define n_env 1) (set! default-material (make dielectric (index n_env))) (define n_wg 2) (define n_sub1 1.45) (define n_sub2 3.5) ; Define structure parameters (define h_sub1 2) ; Thickness of SiO2 substrate (define h_wg 0.12) ; Heigth of waveguide (define w_wg 0.60) ; Width of waveguide ; Build structures (set! geometry (list (make block (center 0 0 (- (/ s_z 4))) (size infinity infinity (/ s_z 2)) (material (make dielectric (index n_sub2)))) (make block (center 0 0 (- (/ h_sub1 2))) (size infinity infinity h_sub1) (material (make dielectric (index n_sub1)))) (make block (center 0 0 (/ h_wg 2)) (size infinity w_wg h_wg) (material (make dielectric (index n_wg)))))) ; Find wavevector corresponding to frequency (define wcen 1.2739) ; Run (find-k NO-PARITY wcen 1 100 (vector3 1 0 0) 1e-4 1.87 1 10 fix-hfield-phas= e output-hfield fix-efield-phase output-efield output-poynting output-epsi= lon) --_000_6D86430ADF9448159F408D6677895727imperialacuk_ Content-Type: text/html; charset="us-ascii" Content-ID: <[email protected]> Content-Transfer-Encoding: quoted-printable <html> <head> <meta http-equiv=3D"Content-Type" content=3D"text/html; charset=3Dus-ascii"= > </head> <body style=3D"word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-lin= e-break: after-white-space;" class=3D""> Dear Steven and MPB's users, <div class=3D""><br class=3D""> </div> <div class=3D"">I am attempting to find the mode structure of ridged SiN (n= ~ 2) waveguides which live on a layer of SiO2 ( ~ 2 um and n ~ 1.45) and w= ith a layer of Si (n ~ 3.5) underneath. The surrounding environment is air.= </div> <div class=3D""><br class=3D""> </div> <div class=3D"">I already know the frequency at which I want to solve the m= odes therefore I am using the find-k function. </div> <div class=3D""><br class=3D""> </div> <div class=3D"">My problem is that the algorithm always seem to find modes = which are localised in the layer of Si and I can not find those which are l= ocalised in the SiN waveguide itself. </div> <div class=3D""><br class=3D""> </div> <div class=3D"">Is there any way I can modify my control file (see bellow) = to find only the modes of interest? Is this an issue because of the enforce= d periodicity of the solutions?</div> <div class=3D""><br class=3D""> </div> <div class=3D"">Thank you for your held and time. </div> <div class=3D""><br class=3D""> </div> <div class=3D"">Sebastien </div> <div class=3D""><br class=3D""> </div> <div class=3D""> <p style=3D"margin: 0px; font-size: 11px; font-family: Menlo;" class=3D"">;= Define the simulation space (a =3D 1um)</p> <p style=3D"margin: 0px; font-size: 11px; font-family: Menlo;" class=3D"">(= define s_y 10)</p> <p style=3D"margin: 0px; font-size: 11px; font-family: Menlo;" class=3D"">(= define s_z 10)</p> <p style=3D"margin: 0px; font-size: 11px; font-family: Menlo;" class=3D"">(= set! geometry-lattice (make lattice (size no-size s_y s_z)))</p> <p style=3D"margin: 0px; font-size: 11px; font-family: Menlo;" class=3D"">(= set! resolution 32)</p> <p style=3D"margin: 0px; font-size: 11px; font-family: Menlo; min-height: 1= 3px;" class=3D""> <br class=3D""> </p> <p style=3D"margin: 0px; font-size: 11px; font-family: Menlo;" class=3D"">;= Not a periodic structure </p> <p style=3D"margin: 0px; font-size: 11px; font-family: Menlo;" class=3D"">(= set! ensure-periodicity #f)</p> <p style=3D"margin: 0px; font-size: 11px; font-family: Menlo; min-height: 1= 3px;" class=3D""> <br class=3D""> </p> <p style=3D"margin: 0px; font-size: 11px; font-family: Menlo;" class=3D"">;= Define dielectric parameters</p> <p style=3D"margin: 0px; font-size: 11px; font-family: Menlo;" class=3D"">(= define n_env 1)</p> <p style=3D"margin: 0px; font-size: 11px; font-family: Menlo;" class=3D"">(= set! default-material (make dielectric (index n_env)))</p> <p style=3D"margin: 0px; font-size: 11px; font-family: Menlo;" class=3D"">(= define n_wg 2)</p> <p style=3D"margin: 0px; font-size: 11px; font-family: Menlo;" class=3D"">(= define n_sub1 1.45)</p> <p style=3D"margin: 0px; font-size: 11px; font-family: Menlo;" class=3D"">(= define n_sub2 3.5)</p> <p style=3D"margin: 0px; font-size: 11px; font-family: Menlo; min-height: 1= 3px;" class=3D""> <br class=3D""> </p> <p style=3D"margin: 0px; font-size: 11px; font-family: Menlo;" class=3D"">;= Define structure parameters</p> <p style=3D"margin: 0px; font-size: 11px; font-family: Menlo;" class=3D"">(= define h_sub1 2) ; Thickness of SiO2 substrate</p> <p style=3D"margin: 0px; font-size: 11px; font-family: Menlo;" class=3D"">(= define h_wg 0.12) ; Heigth of waveguide</p> <p style=3D"margin: 0px; font-size: 11px; font-family: Menlo;" class=3D"">(= define w_wg 0.60) ; Width of waveguide</p> <p style=3D"margin: 0px; font-size: 11px; font-family: Menlo; min-height: 1= 3px;" class=3D""> <br class=3D""> </p> <p style=3D"margin: 0px; font-size: 11px; font-family: Menlo;" class=3D"">;= Build structures</p> <p style=3D"margin: 0px; font-size: 11px; font-family: Menlo;" class=3D"">(= set! geometry (list </p> <p style=3D"margin: 0px; font-size: 11px; font-family: Menlo;" class=3D""><= span class=3D"Apple-tab-span" style=3D"white-space:pre"></span>(make block<= /p> <p style=3D"margin: 0px; font-size: 11px; font-family: Menlo;" class=3D""><= span class=3D"Apple-tab-span" style=3D"white-space:pre"></span>(center 0 0 = (- (/ s_z 4)))</p> <p style=3D"margin: 0px; font-size: 11px; font-family: Menlo;" class=3D""><= span class=3D"Apple-tab-span" style=3D"white-space:pre"></span>(size infini= ty infinity (/ s_z 2))</p> <p style=3D"margin: 0px; font-size: 11px; font-family: Menlo;" class=3D""><= span class=3D"Apple-tab-span" style=3D"white-space:pre"></span>(material (m= ake dielectric (index n_sub2))))</p> <p style=3D"margin: 0px; font-size: 11px; font-family: Menlo;" class=3D""><= span class=3D"Apple-tab-span" style=3D"white-space:pre"></span>(make block<= /p> <p style=3D"margin: 0px; font-size: 11px; font-family: Menlo;" class=3D""><= span class=3D"Apple-tab-span" style=3D"white-space:pre"></span>(center 0 0 = (- (/ h_sub1 2)))</p> <p style=3D"margin: 0px; font-size: 11px; font-family: Menlo;" class=3D""><= span class=3D"Apple-tab-span" style=3D"white-space:pre"></span>(size infini= ty infinity h_sub1)</p> <p style=3D"margin: 0px; font-size: 11px; font-family: Menlo;" class=3D""><= span class=3D"Apple-tab-span" style=3D"white-space:pre"></span>(material (m= ake dielectric (index n_sub1))))</p> <p style=3D"margin: 0px; font-size: 11px; font-family: Menlo;" class=3D""><= span class=3D"Apple-tab-span" style=3D"white-space:pre"></span>(make block<= /p> <p style=3D"margin: 0px; font-size: 11px; font-family: Menlo;" class=3D""><= span class=3D"Apple-tab-span" style=3D"white-space:pre"></span>(center 0 0 = (/ h_wg 2))</p> <p style=3D"margin: 0px; font-size: 11px; font-family: Menlo;" class=3D""><= span class=3D"Apple-tab-span" style=3D"white-space:pre"></span>(size infini= ty w_wg h_wg)</p> <p style=3D"margin: 0px; font-size: 11px; font-family: Menlo;" class=3D""><= span class=3D"Apple-tab-span" style=3D"white-space:pre"></span>(material (m= ake dielectric (index n_wg))))))</p> <p style=3D"margin: 0px; font-size: 11px; font-family: Menlo; min-height: 1= 3px;" class=3D""> <span class=3D"Apple-tab-span" style=3D"white-space:pre"></span></p> <p style=3D"margin: 0px; font-size: 11px; font-family: Menlo;" class=3D"">;= Find wavevector corresponding to frequency </p> <p style=3D"margin: 0px; font-size: 11px; font-family: Menlo;" class=3D"">(= define wcen 1.2739)</p> <p style=3D"margin: 0px; font-size: 11px; font-family: Menlo; min-height: 1= 3px;" class=3D""> <br class=3D""> </p> <p style=3D"margin: 0px; font-size: 11px; font-family: Menlo; min-height: 1= 3px;" class=3D""> ; Run</p> <p style=3D"margin: 0px; font-size: 11px; font-family: Menlo;" class=3D"">(= find-k NO-PARITY wcen 1 100 (vector3 1 0 0) 1e-4 1.87 1 10 fix-hfield-phase= output-hfield fix-efield-phase output-efield output-poynting output-= epsilon)</p> </div> </body> </html> --_000_6D86430ADF9448159F408D6677895727imperialacuk_-- --===============4335723934992296031== Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: base64 Content-Disposition: inline X19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX18KbXBiLWRpc2N1 c3MgbWFpbGluZyBsaXN0Cm1wYi1kaXNjdXNzQGFiLWluaXRpby5taXQuZWR1Cmh0dHA6Ly9hYi1p bml0aW8ubWl0LmVkdS9jZ2ktYmluL21haWxtYW4vbGlzdGluZm8vbXBiLWRpc2N1c3M= --===============4335723934992296031==--