Study Of Polymer Thermo-optical Waveguide Devices Based On Strip-loaded Waveguides

Integrated optoelectronics and integrated optics have developed rapidly and are widely used in the fields of optical communication and optical sensing in order to meet the needs of today's society.Among them,optical waveguide devices,with a series of advantages such as small size,strong functionality,easy integration and good stability,have become an indispensable part of the integrated optics research field,promoting the development of integrated optical chips towards miniaturization,multi-function and practicality.As an important branch,thermo-optic waveguide devices have become more and more important research topics at home and abroad.The optical waveguide thermo-optic switch and the temperature sensor are two typical thermo-optic waveguide devices.Thermo-optic switchs with fast switch time and low power consumption are important components in optical fiber communication with large transmission capacity and high bandwidth.Temperature sensors have a very wide range of applications in medical equipment,consumer electronics,industrial control,environmental monitoring and other aspects.The optical waveguide temperature sensor has become a very important research topic because of its smaller size,lower power consumption,lower cost and high sensitivity.Due to the characteristics of large thermo-optical coefficient,small thermal conductivity,simple preparation process,easy processing,low cost and strong ability to resist electromagnetic interference,polymer materials play an important role in the preparation and research of thermo-optical waveguide devices.In this paper,two kinds of polymer thermo-optical waveguide devices based on strip-loaded waveguide structure are studied in detail and the main contents include:We have synthesized the DR1/SiO₂-TiO₂ organic/inorganic hybrid material independently and characterized its surface morphology,roughness and film thickness with Atomic force microscope?AFM?and Optical microscope.A thermal-optic switch based on organic/inorganic hybrid strip-loaded waveguide structure is designed and fabricated.The device uses SiO₂ as the lower cladding layer,and the polymer P?MMA-GMA?as the upper cladding layer.The optical field is well limited in the lower core layer and the energy loss is reduced by introducing the hybrid waveguide structure that DR1/TiO₂-SiO₂ organic/inorganic hybrid material as lower core layer and SU-8 2005 as upper core layer of the waveguide.The waveguide of the input and output ports of the device was bleached to expand the mode field area of the optical transmission at the device port,the coupling loss between the optical fiber and the switch is effectively reduced,and the air-trenchs structure is introduced to reduce the switching power consumption.By exploring and optimizing parameters of Inductively coupled plasma?ICP?,the best size of air-trenchs structure has been obtained.Optical microscope and scanning electron microscope?SEM?were used to characterize the waveguide structures and air-trenchs structure.The fabricated device were tested and good output spot was obtained.The insertion loss is 11.3 dB and the extinction ratio of the device is 13.4 dB.The response waveform of the device was measured after applying a square wave signal with a frequency of 200 Hz.The switching time is 80?s and 80?s respectively.The switching power consumption is 8.9 mw.Optical waveguide temperature sensor based on strip-loaded optical waveguides structure was fabricated.The size of device is simulated and optimized by COMSOL software,and two interference arms waveguides of MZI are designed into different lengths to control the phase difference of the two branching waveguides.In order to improve the sensitivity of the temperature sensor,we selected the UV curing adhesive Norland73?NOA73?with large thermal light coefficient as the strip-loaded waveguide materials.The DR1/SiO₂-TiO₂ organic/inorganic hybrid material as the material core layer of the waveguide.PMMA grooves and NOA73 strip-loaded waveguide with good morphology were fabricated by ICP etching technique.The DR1/SiO₂-TiO₂organic/inorganic hybrid material film was rotated on the NOA73 strip-loaded waveguide.Change the refractive index of one interference arm in MZI by photobleaching technology,the propagation medium of light transmission in two arms of MZI modulation region is changed.When the ambient temperature is changed,the effective refractive index of the interference arms will changed differently due to the different thermal-optical coefficients of the two media,and the output power will change accordingly.Test results show that the optimized temperature of polymer optical waveguide sensing chip actual sensitivity for-5.25 dB/?.