Dan Jin

Environmental Stress Testing of Electro–Optic Polymer Modulators

Low Vpi electro-optic (EO) polymer modulators were environmental stress tested at both the chip and packaged device level. Different top clad materials showed different results for high-temperature and temperature cycle testing, which is related mostly to coefficient of thermal expansion (CTE) mismatches and/or adhesion properties of the clads related to other materials in the devices stack and to the substrate and electrode materials. With thoroughly compatible cladding, devices that are thermally stable for over 5000 h at 85degC have been achieved. High optical power ( 500 mW @ 1550 nm) tests showed the photochemical stability of the EO polymer material in hermetically sealed packages. The results demonstrate that clad polymers and interactions between devices layers are of concern for achieving environmentally stable EO polymers modulators.

Electro-optic modulator with exceptional power-size performance enabled by transparent conducting electrodes.

An EO phase modulator having transparent conducting oxide electrodes and an inverted rib waveguide structure is demonstrated. This new modulator geometry employs an EO polymer having an in-device r33 = 60pm/V. The measured half-wave voltage Vpi of these devices ranges from 5.3V to 11.2V for 3.8 and 1.5 mm long devices, respectively. The lowest VpiL figure-of-merit corresponds to 0.6V-cm (7.2mW-cm(2) of power length product) in a dual-drive configuration. The trade-off between Vpi, insertion loss and modulation bandwidth is systematically analyzed. An optimized high-speed structure is proposed, with numerical simulation showing that this new structure and an in-device r33 = 150pm/V, can achieve Vpi = 0.5V in a 5mm long active length with dual drive operation. The insertion loss is targeted at 6dB, and a 3dB optical modulation bandwidth can reach > 40GHz.

Optical Signal Processor Using Electro-Optic Polymer Waveguides

We have investigated an optical signal processor using electro-optic polymer waveguides operating at a wavelength of 1.55 mum. Due to recent developments, many useful optical devices have become available such as optical filters, modulators, switches, and multiplexers. It will be useful to have a single optical device, which is reconfigurable to implement all of these functions. We call such a device an ldquooptical signal processor,rdquo which will play a similar role to digital signal processors in electrical circuits. We realize such an optical device in a planar lightwave circuit. Since the planar lightwave circuits are based on the multiple interference of coherent light and can be integrated with significant complexity, they have been implemented for various purposes of optical processing such as optical filters. However, their guiding waveguides are mostly passive, and the only viable mechanism to reconfigure their functions is thermal effects, which is slow and cannot be used for high-speed applications such as optical modulators or optical packet switches. On the other hand, electro-optic polymer has a very high electro-optic coefficient and a good velocity match between electrical and optical signals, thus, permitting the creation of high-speed optical devices with high efficiency. Therefore, we have implemented a planar lightwave circuit using the electro-optic polymer waveguides. As a result, the structure is complex enough to generate arbitrary functions and fast enough to obtain high data rates. Using the optical signal processor, we investigate interesting applications including arbitrary waveform generators.

Photo-Stability Measurement of Electro-Optic Polymer Waveguides With High Intensity at 1550-nm Wavelength

Photo-stability measurements of electro-optic polymer inverted ridge waveguides, fabricated from AJ-CKL1, AJ416 and LPD-80, are conducted up to 30, 100, and 100 mW of input power coupled into the waveguides respectively. These experiments are performed in a N2 atmosphere to exclude absorbed O2. AJ416 and LPD-80 are found to be stable up to at least 1 MW/cm2 at 1550 nm. In contrast, photo-degradation was observed in an ambient atmosphere with 1 mW (LPD-80) and 10 mW (AJ-CKL1) coupled into the waveguides.

Comparison of r 33 values for AJ404 films prepared with parallel plate and corona poling

We report on the measured electro-optic coefficients of approximately 150 pm/V at 1310 nm and 1550 nm for poled guest-host polymer films made with the chromophore AJ404L. Films were poled using corona poling and parallel-plate poling techniques. The films were fabricated and poled and the electro-optic coefficients measured by two independent laboratories. Corona-poled AJ404L films were spun onto indium-tin oxide-coated glass substrates with and without a cladding layer of UV15LV. The r33 value for the films were measured using the Teng-Man technique for both corona-poled and parallel-plate poled films.

Recent advances in commercial electro-optic polymer modulator

We present the state-of-art polymer-based electro-optic modulator, which, for the first time, can be used in real commercial systems. The devices work up to 100 Gbps and possess the Vpi as low as 1.6 V.

Metal-defined polymeric variable optical attenuator

A variable optical attenuator (VOA) based on a metal-defined polymeric optical waveguide has been demonstrated for the first time. The metal film stressor deposited on top of the upper cladding layer not only produces the refractive index change within the core layer, but also acts as a thin-film heater allowing thermal tuning of the optical power within a metal-defined optical waveguide. Fabricated devices exhibit greater than 25 dB of optical attenuation with an applied electrical current of /spl sim/40 mA at 1550-nm wavelength. The switching speed of the VOA exhibits 800 /spl mu/s of rising and 720 /spl mu/s of falling time.