Jie Teng

Athermal Silicon-on-insulator ring resonators by overlaying a polymer cladding on narrowed waveguides

Athermal silicon ring resonators are experimentally demonstrated by overlaying a polymer cladding on narrowed silicon wires. The ideal width to achieve athermal condition for the TE mode of 220 nm-height SOI waveguides is found to be around 350 nm. After overlaying a polymer layer, the wavelength temperature dependence of the silicon ring resonator is reduced to less than 5 pm/degrees C, almost eleven times less than that of normal silicon waveguides. The optical loss of a 350-nm bent waveguide (with a radius of 15 microm) is extracted from the ring transmission spectrum. The scattering loss is reduced to an acceptable level of about 50 dB/cm after overlaying a polymer cladding.

Athermal arrayed waveguide gratings in silicon-on- insulator by overlaying a polymer cladding on narrowed arrayed waveguides

Athermal arrayed waveguide gratings (AWGs) in silicon-on-insulator (SOI) are experimentally demonstrated for the first time to our knowledge. By using narrowed arrayed waveguides, and then overlaying a polymer layer, the wavelength temperature dependence of the AWGs is successfully reduced to -1.5 pm/°C, which is more than 1 order of magnitude less than that of normal SOI AWGs. The athermal behavior of the AWGs is obtained with little degradation of their performance. For the central channel, the cross talk is less than -15 dB and the insertion loss is around 2.6 dB. Good characteristics can be maintained with temperatures up to 75 °C. The total size of the device is 350 μm × 250 μm.

A PSQ-L Polymer Microring Resonator Fabricated by a Simple UV-Based Soft-Lithography Process

Photonic integrated circuits based on polymer waveguides have great potential as low-cost optical devices. A novel inorganic-organic hybrid polymer polysiloxane-liquid (PSQ-L) is introduced for defining the waveguides and for use as both core and cladding layer for the waveguides. The waveguide circuits are replicated by a simple ultraviolet-based soft lithography method consisting of two steps. All-polymer microring resonators are fabricated by this approach and characterized. About 6-dB extinction ratio at the through port and 18-dB extinction ratio at the drop port is demonstrated. A Q-factor of 4.2 times 104 is obtained. Extracted from the measured spectrum, the scattering loss of the ring waveguides is estimated to be about 1.6 dB/cm. This easy fabrication technique can be easily extended to fabricate other devices.

UV-soft Imprinted Tunable Polymer Waveguide Ring Resonator for Microwave Photonic Filtering

A tunable polymer waveguide ring resonator is proposed and demonstrated for microwave photonic filtering. The ring resonator consists of a Mach-Zehnder interferometer (MZI) as the tunable coupler and two micro-heaters as the thermo-optic phase shifters. It was fabricated with inorganic-organic hybrid optical material polysiloxane-liquid series by a novel and simple UV-soft selective imprint technique. The coupling conditions, over-, critical- and under-coupling, were obtained with the micro-heater on the arm of MZI and the maximum notch depth of about 18 dB was achieved. The resonant wavelength was also tuned with the micro-heater on the ring waveguide. The dispersion induced power fading of radio over fiber link was overcome by the tunable ring resonator with its notch filtering function.

Optical properties of polymer poly(phthalazinone ether sulfone ketone) film waveguide

The optical properties of novel polymer poly(phthalazinone ether sulfone ketone, PPESK) film waveguide are studied by prism coupler. The optical properties of PPESK-8020, including refractive index, birefringence, thermo-optical coefficient and optical loss, are demonstrated. This kind of material has the advantages of low optical loss (less than 0.24 dB/cm at 1310 nm and 0.52 dB/cm at 1550 nm) and high thermal stability (1% weight loss temperature: 488 centigrades). Due to these excellent properties, it may have great potential in optical waveguide applications.

Optical biosensors utilizing polymer-based athermal microring resonators

Optical waveguide biosensors are attracting more and more attentions and presenting great potential applications. Polymer-based optical biosensors are promising for the their unique advantages: low cost, easy fabrication, possibility of functionalization with chemicals for the detection of biological molecules, and flexible operating wavelength in both the infrared communication wavelength band (1310-1550nm) and the visible wavelength region (500-800nm). Operating in the visible wavelength, the optical biosensing can avoid the high optical absorption loss of water solution, which can hardly be done for Si-based optical sensors. In this paper, an optical biosensor utilizing polymer-based athermal optical waveguide microring resonator is presented. The athermal design of the microring resonator can make the resonant wavelength drift with temperature be greatly reduced, and an optical biosensing platform with high thermal stability can be achieved. The simulation results show that the maximal resonant wavelength drift is -0.0085nm when the temperature varies from 20°C to 65°C and the maximal wavelength drift slope is -0.0009nm/K. With the microring resonators fabricated by using a simple UV based soft imprint technique with self-developed UV-curable polymer PSQ-L materials, experimental investigations on the specific surface detection of target molecules have been preliminarily performed. The results shows that the optical biosensors based on the polymer optical microring resonators would have potential applications for label-free surface sensing.

A low cost photonic biosensor built on a polymer platform

Planar integrated optical biosensors are becoming more and more important as they facilitate label-free and real time monitoring biosensing with high sensitivity. In this paper, the systematic research on one kind of optical biosensor, based on a resonant principle in a polymer ring resonator, will be presented. Reduced footprint and high sensitivity are advantages of this kind of biosensor. Rather than expensive CMOS fabrication, the device with high performance is fabricated through a simple UV based soft imprint technique utilizing self-developed low loss polymer material. The measurement results for the bulk sensing of a NaCl solution and the surface sensing of a minimal amount of avidin molecules in a buffered solution will be presented.

Quasi-single-sideband radio over fiber transmission with a polymer-based waveguide microring resonator

Integrated waveguide microwave photonic filters (MPFs) have the potential to bring down volume, weight, and power consumption of signal processing equipment besides the common advantages of discrete-component-based MPFs. A polysiloxane-liquid polymer-based optical wave-guide microring resonator was designed and fabricated by a simple ultraviolet-based soft-imprint technology, with which the quasi-single-sideband filtering for the 10 to 22 GHz microwave signal was realized and 20 Mbps quadrature phase shift keying signal carried by 14.35 GHz microwave transmission over a 25 km single mode fiber was demonstrated.

Athermal SOI ring resonators by overlaying a polymer cladding on narrowed waveguides

Athermal silicon ring resonators are experimentally demonstrated by overlaying a polymer cladding on narrowed silicon wires. The wavelength temperature dependence of the silicon ring resonator is reduced from 54.2 pm/°C to −4.9 pm/°C.

Recent progress on polymer photonic materials and optical waveguide devices

Recent progress in research on polymer photonics is reviewed in this paper, including new concepts of polymer-based photonic materials, components and devices. Novel polymer photonic materials developed in our photonic research group, polysiloxanes (named as PSQ-Ls), are reported, including two kinds of PSQ-Ls, named as PSQ-LL and PSQ-LH. These polymer photonic materials are of a liquid and can be cured by UV light irradiation or by heat. The characterization of the optical films and waveguides based on the novel polymer materials, including refractive index, birefringence, optical loss and thermal stability, is given in detail. By blending PSQ-LL and PSQ-LH, the refractive indexes can be tuned linearly from 1.4482 to 1.5212 at 1310nm and from 1.4478 to 1.5198 at 1550nm. The birefringence is below 0.0005 with the variation of PSQ-LL content. These materials exhibit low optical losses of 0.31dB/cm at a wavelength of 1310nm and 0.70dB/cm at 1550nm, and high thermal stability with 1% decomposition temperatures of 297°C (in air) and 340°C (in N2) for PSQ-LH, and 313°C (in air) and 370°C (in N2) for PSQ-LL. Optical waveguide components such as micro-ring resonators and waveguide gratings based on PSQ-Ls are fabricated by photolithography-etching method and by UV imprint technology, respectively. The experimental measurements show that the polymer-based micro-ring resonators exhibit an excellent resonant filtering function. Potential applications of the polymer-based micro-ring resonators for optical communications and optical sensing are discussed.