Yunfei Yan

Low-power and high-speed thermo-optic switch using hybrid silica/polymer waveguide structure: design, fabrication and measurement

Response speed and power consumption are improved for a Mach–Zehnder interferometer (MZI) thermo-optic (TO) switch, by using a hybrid silica/polymer waveguide structure and optimizing both the thickness of the silica under cladding and that of the PMMA-GMA upper cladding. Fabrication techniques, including chemical vapor deposition (CVD), spin-coating and wet-etching, are adopted to develop the switch sample. Under 1550 nm wavelength, the driving powers under ON and OFF states are measured to be 0 and 13 mW, respectively, indicating a switching power of 13 mW. The fiber-to-fiber insertion loss under the ON state is 15 dB, the extinction ratio between the ON state and the OFF state is 18.3 dB, and the rise time and fall time are 73.5 and 96.5 µs, respectively. Compared with the TO switches based on Si/SiO2 or all-polymer waveguide structure, the proposed device possesses both low power consumption and fast response speed, by virtue of the large TO coefficient of the polymer core, thin upper/under claddings and the large thermal conductivity of silica.

FABRICATION OF A POLYMER-ON-SILICA HYBRID THERMO-OPTIC SWITCH WITH FAST RESPONSE TIME AND LOW POWER CONSUMPTION

A polymer-on-silica Mach–Zehnder interferometer (MZI) TO switch is experimentally demonstrated using core polymer material with large thermo-optic (TO) coefficient. In the hybrid structure, the negative photoresist SU-8 and silica are used as core and lower cladding, respectively. Wet-etching technique is adopted to optimize fabrication process and diminish sidewall roughness and scattering loss. Compared to our two previously reported works, this switch exhibits better performance with lower power consumption of less than 4.8 mW, higher extinction ratio of 22.5 dB, shorter rise time of 141 μs and fall time of 87 μs, due to the larger thermal conductivity of silica relative to polymer in the proposed hybrid configuration.

Nanosecond Bias-Free Mach–Zehnder Electro-Optic Switch Based on Dye-Doped Polymer DR1/SU-8 and Microstrip Line Electrode

Abstract A bias-free Mach–Zehnder interferometer electro-optic switch is demonstrated with a dye-doped polymer Disperse Red 1 (Tokyo Chemical Industry, Co., LTD, Tokyo, Japan)/SU-8 (MicroChem Corp., Newton, Massachusetts, USA) and microstrip line electrode. The device is carefully designed and optimized for bias-free function and high-speed switching using the three-dimensional beam-propagation method and extended point-matching method, and the switch is seriously fabricated by a wet-etching technique and inductively coupled plasma etching technique for good control of dimension parameters. The measured rise time and fall time at 1,550 nm are both at the level of ~10 ns. Owing to the bias-free function and nanosecond response speed, this switch exhibits potential applications of high-speed optical routing and exchanging.

Fast response 2 \times 2 thermo-optic switch with polymer/silica hybrid waveguide

A polymer/silica hybrid 2 \times 2 multimode-interference Mach–Zehnder interferometer thermo-optic (TO) switch is designed and fabricated. Instead of polymer, silica is used as under-cladding to accelerate heat release because of its large thermal conductivity. The developed switch exhibits low power consumption of 6.2 mW, low crosstalk of about –28 dB, and short response time. The rise and fall times of 103 and 91 \mu s for this hybrid switch are shortened by 40.8% and 52.4%, respectively, compared with those of the fabricated TO switch (174 and 191 \mu s) using polymer as both upper- and under-claddings.

FABRICATION OF SU-8 BASED ELECTRO-OPTIC SWITCH USING ALL-WET ETCHING TECHNIQUE

Polymeric Disperse Red 1 (DR1)/SU-8 electro-optic (EO) switch incorporating inverted-rib waveguide structure is designed and fabricated by all-wet etching process. The guest-host EO material DR1/SU-8 has been successfully synthetized and its optical properties are characterized in detail. The DR1/SU-8 material presents a low processing cost, an excellent photostability and a large EO coefficient of 15.4 pm/V. The characteristic parameters of both the inverted-rib waveguide and the coplanar waveguide electrodes are carefully designed and simulated. By all-wet etching process, the optimized Mach–Zehnder interferometer switch is successfully fabricated with a lower fiber-to-fiber insertion loss of 9.6 dB. The switch rise time and fall time are 322 ns and 294 ns, respectively.

Low power 2×2 thermo-optic polymer waveguide switch

A low-power 2×2 multimode interference-Mach Zehnder interferometer thermo-optic switch is proposed and fabricated using a cross-linkable negative photoresist as core material. The waveguide can be easily fabricated by direct ultraviolet photolithography and wet etching processes. The experiment results show that the switch has a low switching power of 6.9 mW and a switching time of 0.4 ms.

Errata: Low power 2x2 thermo-optic polymer waveguide switch

This PDF file contains the errata for “OE Vol. 49 Issue 01 Paper OE ERR-JAN2010-1” for OE Vol. 49 Issue 01