Araz Yacoubian

Three-dimensional integrated optics using polymers

Some of the key components are demonstrated to make three-dimensional (3-D) optical integrated circuits possible using polymers. Fabrication techniques of shadow reactive ion etching, shadow photolithography, and gray-level photolithography to produce complex 3-D integrated optic structures are demonstrated. Vertical waveguide bends exhibit excess losses of <0.3 dB, and vertical power splitters possess predictable output splitting ratios between multiple core levels with excess losses of <0.5 dB. Vertical polarization splitters exhibit power extinction ratios of 15 dB between the output core layers. A 1/spl times/4 vertical-horizontal power splitter is also demonstrated. Additionally, these techniques are used to integrate different polymer materials into the same optical circuit while easily solving the mode mismatch problem. To show the technique, a polymer electrooptic modulator is vertically integrated with a low-loss waveguide.

Enhanced optical modulation using azo-dye polymers

The performance of the conventional azo-dye polymer modulation system is compared with that of the recently developed attenuated-total-reflection (ATR) dye-polymer modulation techniques. Experiments based on Fabry-Perot resonance shifting in ATR geometry indicate that the modulation parameters, namely, speed, contrast, and efficiency, are enhanced. Although the dye-polymer response still remains fairly slow, ATR methods provide substantial improvement over the existing system. An all-optic long-range surface-plasmon azo-dye polymer modulation system is also proposed. Computer simulation of the reflectance and the photoinduced resonance shifting suggest that the proposed system can be used effectively for all-optic modulation. Some of the limitations of both systems and a pratical application of the ATR modulation methods are discussed.

EO polymer-based integrated-optical acoustic spectrum analyzer

An acoustic spectrum analyzer based on electrooptic (EO) polymer integrated optics is presented. The device is used in a scanning heterodyne geometry by zero biasing a Michelson interferometer. It is capable of detecting vibrations from DC to GHz range. The novelty of the work is applying EO polymers to high frequency acoustic sensing applications. EO polymers have been extensively used for communication devices. However, their use in high frequency sensing applications remains unexplored. The sensor presented is designed to analyze thin film structure by utilizing high frequency capabilities of EO polymers. The advantage of this approach over existing methods is in its potential to detect vibrations over 100 GHz with low drive voltages (V/sub /spl pi// less than 1 V), using a device that is completely electrically controlled with no mechanical moving parts. Low frequency tests indicate good agreement between experimental results and theoretical predictions. Acoustic vibrations excited by pulsed Nd-YAG laser are detected to frequencies up to 200 MHz using the device presented.

Vertically integrated polymer waveguide device minimizing insertion loss and Vπ

We present design and fabrication considerations for a vertically integrated electro-optic polymer modulator. The hybrid design incorporates both passive and active core segments for optimized transmission and modulation of an optical signal. When compared to traditional structures, this vertically integrated modulator potentially reduces fiber coupling and propagation losses by more than 10 dB for a 6 cm structure while maintaining a minimized V(pi ).

Three dimensional integration of polymer electro-optic modulators

The proposed structure consists of a vertical power splitter that divides the fiber coupled optical input among the vertical layers. Modulators on each layer share a common intermediate ground plane which provides electrical isolation. We will present preliminary beam propagation simulation, fabrication, and experimental results including the required drive voltages, crosstalk, and insertion losses of the individual modulators.

Bragg gratings by photo-bleaching in polymer waveguides

Recent advances in polymers have resulted in various demonstrations of polymer based devices and components for integrated optics, optical communications, RF photonics and sensors.

Holographic recordings on 2-hydroxyethyl methacrylate and applications of water-immersed holograms

A new holographic recording medium based on poly-2-Hydroxyethyl Methacrylate (HEMA) and visible light sensitizer is investigated. The holographic recordings are based on photo- induced polymerization of HEMA, using Camphorquinone as a visible light sensitizer. The medium has several advantages. Namely, it does not require extensive processing and survives high humidity conditions, including water immersion. Several experiments have been conducted to analyze the behavior of this medium, including analysis of recording parameters using a real-time holographic recording/playback setup, precuring, swelling, and water survivability tests. Water-immersion survivability of our material is a unique characteristic that can be incorporated in novel holographic and optical systems, such as water immersed holographic optical elements. New possibilities and applications are discussed.

Azo-dye polymer-based modulation in total internal reflective Fabry-Perot geometry

Azo dye polymers have been investigated as polarization holographic recording and all-optical modulating media. The use of azo dye polymers is limited by their intrinsic low response time. Different dyes and fabrication techniques have been utilized to enhance the materials speed. A relatively new modulation technique utilizing the nonlinear Fabry-Perot effect in attenuated total internal reflection (ATR) geometry is compared to the conventional transmission type modulation geometry. In the ATR case, a small change in the index of the polymer causes a shift in the angular spectrum of the Fabry-Perot resonances, thus enabling us to modulate a probe beam with an external pump beam. Both modulation speed and contrast ratio are greatly enhanced using this technique. Experimental results are presented, and the limits of both methods are analyzed. The ATR method is also useful in characterizing thin (less than a few microns) polymer films, for studying photo-induced index changes. Future applications, such as optically addressed spatial light modulators and nonlinear optical processing applications, are discussed.