Polymeric optical waveguide has become the hotspot in recent years

it provide an alternative approach for realizing the next generation of optoelectronic integrated circuits because of a series of merits:(1)In comparison with the traditional material

polymer waveguides are easy to fabricate on almost any substrate of interest which reduces manufacturing costs and opens the possibility of single-chip integration with active components

such as lasers

modulators

and detectors;(2)The refractive indexes of polymer waveguide materials can be adjusted widely to address the compromise between coupling losses and bending losses;(3)Additionally

the thermo-optical coefficient of polymer materials can be greater than that of SiO

2

and far more than an order of magnitude

while polymers’ thermal conductivities are a fraction of SiO

2

and silicon’s.Polymeric Y-junction waveguide is the key component in fabricating polymeric electro-optic devices

such as intensity modulators

optical switches and so on.Single mode propagation is an important requirement for optical waveguide devices for use with single-mode fiber

it can reduce the coupling loss.In this paper

a technique is used for calculating the field distribution of the polymeric Y-junction rib waveguide.The technique is based on the combination of the effective index method(EIM) and the variational method(VM)

it is mixed between the advantages of each method and avoided their disadvantages

where EIM can make the calculations procedures simple but it has some difficult to find the field distribution

other wise

VM can be used with very good accuracy to find the field distribution.An algorithm is implemented to study the effect of the structure parameters on the field distribution of the polymeric Y-junction rib waveguide.The obtained single mode rid waveguide structure parameters are:the core thickness is 1.5 μm

the rib height is 0.2 μm

and the rib width is 5 μm.