Polymeric materials, in both fiber and planar form, are finding increasing application in commercial optical communication systems. This paper compares and discusses the intrinsic optical properties of common organic materials used in polymer waveguides as relates to their expected performance in optical fibers and rare earth amplifiers. Specifically considered and compared are polymethyl methacrylate (PMMA), Teflon-AF, Cytop, and perfluorocyclobutyl (PFCB) polymers.

We synthesized novel cross-linkable fluorinated co-poly(arylene ether sulfide)s and co-poly(arylene ether sulfone)s for optical waveguide applications, having high thermal stability, high optical transparency in the infrared communication region, and small birefringence. The refractive index of the materials can be easily controlled in the range of 1.50~1.58 by changing the copolymer composition in the materials. The birefringence of the polymer films was 0.0015~0.0039 at the wavelength of 1.55 μm. These are much lower than those of fluorinated polyimides for optical waveguides. The optical loss after storing at 300 °C for 1 h remains almost constant, demonstrating the thermal stability. The propagation losses of the fluorinated polymers were 0.1~0.3 dB/cm and 0.2~0.5 dB/cm at the wavelength of 1.3 and 1.55 μm, respectively. These excellent optical properties have allowed us to fabricate a variety of optical devices such as straight channel waveguides, directional coupler, and polymeric wavelength filter.

A wide variety of aromatic trifluorovinyl ether monomers and highly fluorinated crosslinkable dendrimers have been developed via novel synthetic strategies. Through the thermal dimerization of trifluorovinyl ether moieties on the monomers or on the periphery of dendrimers, these monomers or dendrimers can be melt or solution polymerized to form perfluorocyclobutane(PFCB)-containing prepolymers with good processability for optical waveguide fabrication. By further thermal crosslinking, the resulting thermoset materials possess low optical loss (0.3-0.4 dB/cm at 1310 nm with 1% of DR-1 or DCM doping), high thermal stability (T_g: 100-400 °C), good thermo-optic property, high solvent and humid resistance, and excellent mechanical flexibility. The combination of processability and performance in these PFCB-containing thermoset materials make them as ideal candidates for the fabrication of high-performance polymeric planar lightwave circuit components with the applications in the telecom and datacom optical networks.

We report on optical transmission properties and results of optical waveguide characterization of flourinated hyperbranched polymers and dendrimers (details on chemical synthesis were reported recently [1]). The polymers and dendrimers allow the introduction of additional functionality, such as cross-linking and refractive index tuneability. The dendrimers having a similar bulk structure as the hyperbranched polymer were also shown to house lanthanide cations for optical amplifying application. The fluorinated bulk structure results in a low contribution from vibration overtones in the absorption spectra in the NIR/IR region (800 - 2200 nm). The refractive index of the fundamental fluorinated hyperbranched polymer was found to be tuneable between ca 1.45 and 1.65 by incorporating various substituents. Optical losses were measured to be below ca 0.5 dB/cm at 1550 nm.

We reported experimental results of the resonant scattering of light from a system prism-glass/Ag/MgF₂/air in the ATR-Kretschmann configuration, for p-polarized light incident by the glass side. The thickness of the dielectric film is chosen in such a way that in the absence of roughness the system supports 3 transverse magnetic (TM) guided modes, at a wavelength λ = 632.8 nm of the incident light. The scattering is due to the natural roughness of each interface of the system, while the resonant character of the scattering is due to the excitation of the guided modes and their interaction with the interfaces roughness. The scattered light shows six peaks at angles given by θ₁ = ± 61.65 ⁰, θ₂ = ± 53.69 ⁰, and θ₃ = ± 43.40 ⁰, for any angle of incidence. These angles correspond to the excitation of the guided modes. The scattering response is enhanced when the angle of incidence is equal to one of the angles of excitation of the guided modes.

Monolithic fabrication of submicrometer multiple-pitch gratings by use of a single computer-generated phase mask(CGPM) is proposed. The CGPM is a computer-generated Fourier hologram generating multiple diffracted beams with equal intensity from a single incident beam. The submicrometer grating periods differing by as little as a few angstroms are estimated with basis of multiple diffraction angles and it is compared with experimental results.

Perfluorocyclobutyl (PFCB) polymers and copolymers enjoy a unique combination of properties well suited for optical applications such as high temperature stability, precisely controlled refractive index, low moisture absorption, excellent melt and solution processability, a variable thermoptic coefficient, and low transmission loss at 1300 and 1550 nm. Copolymerization reactions offer tailored thermal and optical properties by simple choice of comonomer. PFCB copolymers can be solution or melt microfabricated via standard methods and can also be processed via micro-transfer molding in photolithographically generated features. Reliable molding of polymer waveguides offers significant potential to reduce photonic integrated circuit (PIC) fabrication costs and enable the realization of compact, integrated subsystems for a variety of applications. Copolymerization chemistry, thermoptic measurements, and initial results on the first micro-transfer molded waveguide structures are presented.

An optical low coherence interferometer was built and used to characterize the optical performance of planar arrayed-waveguide grating (AWG) devices. The phase error and amplitude distributions of individual waveguides in an AWG were extracted by sectioning individual interferograms from the low coherence interferometer. Using a large amount of oversampling to improve signal-to-noise in combination with Hilbert transformation method, phase errors of less than λ/300 in our AWG’s were achieved and correlated to fabrication variations from the waveguide device design. This was subsequently used to improve the performance of our devices. In addition, the group delay (GD) and chromatic dispersion (CD) were also derived from the measured phase error using a Fourier transform method. The derived GD and CD matched well with those directly measured from commercial chromatic dispersion equipment based on the phase modulation method. The relationship between the phase and amplitude errors with different frequencies and the variation of GD or CD will be discussed.

We present recent significant progress in the fabrication of polymer Bragg gratings suitable for telecom applications. We demonstrate that polymer Bragg gratings can be thermally tuned over 20nm with polarization sensitivity less than 0.05nm. Experimental data are presented to address issues of long-term performance stability, propagation loss, polarization sensitivity and practical wavelength tuning. Polymer Bragg gratings are shown to survive very stringent accelerated aging tests and exhibit long-term stability in both material properties and grating performance. The spectral performance of the gratings and example telecom applications employing polymer Bragg gratings are also discussed.

The waveguide design and second harmonic generation experiment within inverted and non-inverted waveguides is discussed. The effect on phase-match and overlap integral, of an interlayer having different refractive index into the core region of the waveguide is investigated. The experimental waveguide is made of two identical Langmuir-Blodgett films with 2-docosylamino-5-nitropyridine. Both thin films and waveguide characterisation are presented including a detailed description of the experimental set-up. An inverted waveguide is produced by a proper arrangement of the thin organic films. With a tunable laser source, phase-matching of SHG is proven.

Tailored functionality, compactness, and reliability continue to be needed in optical communication devices. Our processes for prototyping and validating low-loss planar polymer waveguide devices can respond rapidly to these needs through the steps described herein. In the past two years we have prototyped several distinct thermo-optic devices and established process- and product-reliability that is broadly applicable. Our prototyping and validation processes consist of modeling, waveguide fabrication for verification of design rules, optical characterization, heater fabrication (for thermo-optic devices), and bare-chip accelerated aging. First, modeling provides insight into optimized designs that can be fabricated with low-loss polymers. These designs are subsequently verified by experiment. Optical building blocks, such as bends, splits, and crossovers, have been characterized, and selected for use in the design of devices for applications such as switching, variable attenuation, and wavelength selection. Resistance heater dimensions and waveguide structures are optimized for maximum thermo-optic effect, minimum response time, and operational stability. As an example, a 2x2 thermo-optic switch, characterized at 1550 nm, has a maximum insertion loss of 1.8 dB, polarization dependent loss less than 0.1 dB, and switching time of less than 3ms. A robust waveguide fabrication process combined with a rapid prototyping ability provides the ability to efficiently evaluate design options. Short term and long term statistical data show that the fabrication process is in good control. Environmental screening tests combined with high temperature aging under various conditions of atmosphere and electrical power provide an efficient means to evaluate materials and processes, estimate product lifetime, and isolate failure mechanisms.

Optical backplanes are attractive components for systems with high data rates between subsystems and a large number of interconnects. An optical backplane which uses multimode polymer waveguides was originally developed for avionic applications but can be used in telecom switching systems as well. For transmission distances in the range of 100cm and data rates up to 10Gbps, the modal dispersion can be negelected. The waveguides are fabricated on large substrates (aluminum, FR4 and others) by a direct writing technique. Splitters and couplers can be fabricated with the same technique. The waveguides have a low loss (0.04dB/cm) and high temperature stability (up to 250°C) and are used with 840nm vertical cavity lasers. The waveguide cross section can be chosen between approx. 250μm x 250μm and 50μm x 50μm. We have successfully transmitted up to 10Gbit/s over multimode polymer waveguides with lengths of 100cm. A free space, expanded beam coupling is used for the board-backplane transition, resulting in high alignment tolerances. The overall insertion loss for a backplane connection is typically between 2 and 8 dB, depending on waveguide length, radius of curvature, number of waveguide crossings etc. A typical transceiver power budget of 15-20dB allows the integration of star couplers with up to 16 ports. Several test systems with different interconnection schemes have been realized and tested. Tests include mechanical stability (vibration), thermal stability (cycles, shocks and accelerated aging) and gamma irradiation as well as optical power levels, signal integrity and bit error rates.

Organic electroluminescent diode (OELD) has been investigated for use as a light source of polymeric optical integrated devices for use as an optical interconnects in data communication systems. Several kind of OLED has been investigated for a light source of optical integrated device. The OELDs consist of indium-tin-oxide (ITO) coated substrates, hole-transporting layer of α-NPD (4,4'-bis[N-(naphthyl)-N-phenyl-amino]-biphenyl), an emissive layer and silver containing magnesium cathode. The OLED was fabricated by organic molecular beam deposition (OMBD) technique. As an emissive layer, rubrene (5,6,11,12-tetraphenylnaphthacene) doped Alq₃ (8-hydroxyquinoline aluminum), with an emission peak center at 560 nm, was employed. Optical pulses of faster than 100 Mb/s have been generated from the OELD. The OLEDs were fabricated on a glass substrate and a polymeric substrate. The device fabricated on a polymeric substrate shows similar device characteristics to that on a glass substrate. Emission characteristics and the pulse response characteristics of the OLED as regards it use as a light source for the polymeric waveguide have been discussed.

We present a novel design for miniature and low-cost Surface Plasmon Resonance (SPR) sensor chip for which we employ the polymer optical waveguide fabrication technique. The chip is 12.5 mm x 30 mm with four measurement channels. This SPR sensor chip can detect changes in the refractive index of an analyte by measuring the SPR wavelength shift in the spectra of transmitted light. We evaluated the SPR refractive index sensitivity of this device for liquid sample.

The understanding of light propagation primarily derives from studies of isotropic media. The law of refraction predicts that the tilt of a beam traversing an interface between two media will monotonously grow with the angle of incidence. The law of diffraction predicts beam spreading being completely determined by the ratio of wavelength and width, only slightly affected by the refractive index and independent of the tilt. In this paper, we demonstrate anomalies in light refraction and diffraction in evanescently coupled waveguide arrays ('discrete' refraction and diffraction). We have studied the propagation of beams in these arrays. It turned out that refraction and diffraction exhibit strong anomalies as they depend periodically on the initial beam tilt. In contrast to isotropic systems we found that transverse energy transport cannot exceed a certain maximum velocity and that the diffractive spreading depends on the direction of propagation, i.e., by varying the angle of incidence, size and sign of diffraction can be controlled and it can even be arrested. For particular initial tilts the array can undo beam spreading. The experiments were performed on homogeneous arrays of 75 waveguides in an inorganic-organic polymer on thermally oxidized silicon wafers. The 6 cm long samples were fabricated by UV-lithography on 4" wafers. Each waveguide provided low loss single mode waveguiding (<0.5 dB/cm) at λ= 633 nm. The uniform separation of adjacent guides was chosen for efficient evanescent coupling. The theoretical explanation of the measured effects was done based on coupled mode theory.

Planar waveguides have been prepared on the ZrO2-(3-glycidiloxypropyl)trimethoxysilane (GPTS) system. Stable sols containing ZrO2 nanoparticles have been prepared and characterized by Photon Correlation Spectroscopy. The nanosized sol was embedded in (3-glycidoxipropil)trimethoxisilane (GPTS) used as a hybrid host for posterior deposition. The optical parameters of the waveguides such as refractive index, thickness and propagating modes and attenuation coefficient were measured at 632.8, 543.5 and 1550 nm by the prism coupling technique as a function of the ZrO2 content. The planar waveguides present thickness of a few micra and support well confined propagating modes. Er3+ doped samples display weak and broad (Δλ≈96nm) emission at 1.5μm.

Parallel optical interconnection modules has been used for inter- and intra- hardware systems to overcome the bottleneck of electrical interconnection. The next-generation high-throughput telecommunication systems over several tera-bit-per second and high-speed computer systems over several GHz require chip-level optical interconnection as well as MCM-level optical interconnection. This paper describes chip-level optoelectronic packaging technologies to construct future high-performance telecommunication and computer hardware systems. The key technologies include optoelectronic chip on film(OE-COF) packaging technology, and fiber-less optical I/O-BGA packaging technology using microlenses for optical input or output terminals. The OE-COF is composed of flip-chip bonded optical devices and LSIs on the optical waveguide film with impedance-matched electrical lines for flexible OE packaging. The BGA package can allow wide-misalignment of ±50μm, which is compatible with the performance of current electronic assembly machines, and is useful for high-density and low-cost packaging on boards.