![](https://csdnimg.cn/release/download_crawler_static/16720200/bg4.jpg)
The relations can be written as
dn
LR
nj
xj
sc
Δ
=
Δ
Δ
(3)
where Δx is the output waveguides separation, and R is the focal length. The variation of the
focal position x will depend on the index migration Δn
c
. When the thermal shift from (T
0
-jΔT)
to (T
0
+ jΔT), the beam will export from channel –j to channel j. Then the wavelength-
channel-selective function is realized.
Fig. 1. Schematic diagram of the monolithically multi-functional integrated interleaver module.
2.2 Analysis and simulation of wavelength transfer matrix
To ensure the low-loss single-mode polymer optical waveguide for planar lightwave circuits
(PLCs), Negative-type fluorinated photoresist and organic-inorganic grafting PMMA were
used as the waveguide core and cladding, respectively. Highly fluorinated polystyrene
derivates (FPSDs) [27] were synthesized by copolymerization of 2,3,4,5,6-pentafluorostyrene
(PFS) and fluorinated styrene derivate monomer (FSDM). The fluorinated polymers were
doped into fluorinated bis-phenol-A novolac resin (FSU-8) using diphenyl iodonium salt as a
photoacid generator (PAG). The refractive index and crosslinking density of the negative-type
fluorinated photopolymer can be tuned and controlled by monitoring the feed ratio of
comonomers. The SiO
2
-TiO
2
network grafting PMMA material [28] offers several advantages
such as low birefringence, good thermal stability and low wavelength dispersion. The
refractive index of the sol-gels can be adjusted by monitoring the composition of TiO
2
in
hybrid materials. The refractive indices (n) of the polymeric core and cladding materials
measured with an M-2000UI variable angle incidence spectroscopic ellipsometer are 1.571
and 1.560 at 1550-nm wavelength, respectively. The relative refractive index difference
between the core and the cladding is about Δ = (n
1
-n
2
)/n
1
= 0.7%. The design parameters of
the cascaded AWGs are given in Table 1.
Received 22 May 2014; accepted 18 Jul 2014; published 11 Aug 2014
25 August 2014 | Vol. 22, No. 17 | DOI:10.1364/OE.22.019895 | OPTICS EXPRESS 19898