Polymer Waveguide Technology Research Articles

Multichannel laser diode to polymer waveguide array coupling with a double-aspheric lens

An optical system for multichannel coupling of laser arrays to polymer waveguide array probes with a single biconvex lens is developed. The developed cylindrical module with 13 mm and 20 mm in diameter and length, respectively, enables coupling of eight individual optical channels using an aspheric lens. Specific coupling with crosstalk below −13dB for each channel and quasi-uniform coupling over all channels is achieved for a waveguide array with 100 µm lateral facet pitch at the incoupling site. The polymer waveguide technology allows for tapering of the lateral waveguide pitch to 25 µm toward the tip of the flexible waveguide array. SU-8 and PMMA are used as the waveguide core and cladding, respectively. The optical coupling module is designed as a prototype for preclinical evaluation of optical neural stimulators.

Polymer waveguides for electro-optical integration in data centers and high-performance computers.

To satisfy the intra- and inter-system bandwidth requirements of future data centers and high-performance computers, low-cost low-power high-throughput optical interconnects will become a key enabling technology. To tightly integrate optics with the computing hardware, particularly in the context of CMOS-compatible silicon photonics, optical printed circuit boards using polymer waveguides are considered as a formidable platform. IBM Research has already demonstrated the essential silicon photonics and interconnection building blocks. A remaining challenge is electro-optical packaging, i.e., the connection of the silicon photonics chips with the system. In this paper, we present a new single-mode polymer waveguide technology and a scalable method for building the optical interface between silicon photonics chips and single-mode polymer waveguides.

Low-crosstalk high-density polymeric integrated optics incorporating self-assembled scattering monolayer.

Highly integrated optical components are strongly demanded because they enable wavelength-division multiplexing optical communication systems to achieve smaller footprints, lower power consumption, and enhanced reliability. Variable optical attenuator (VOA) arrays are often used with optical switches in cascaded form for reconfigurable optical add-drop multiplexer systems. Although VOAs and optical switches based on polymer waveguide technology are commercially available, it is still not viable to integrate these two array devices on a single chip because of significant interchannel crosstalk. In this work, we resolved the issue of crosstalk and integrated the arrays of optical switch and VOA on a single chip by incorporating a self-assembled scattering monolayer (SASM). The SASM was effective for scattering the planar guided mode; consequently, the crosstalk into an adjacent channel was significantly reduced, to less than -35 dB.

Integrated-optic polarization controllers incorporating polymer waveguide birefringence modulators

Polarization controllers based on polymer waveguide technology are demonstrated by incorporating thermo-optic birefringence modulators (BMs) and thin-film wave plates. Highly birefringent polymer materials are used to increase the efficiency of birefringence modulation in proportion to the heating power. Thin-film quarter-wave plates are fabricated by using a crosslinkable liquid crystal, reactive mesogen, and inserted between the BMs to produce static phase retardation and polarization coupling. By applying a triangular AC signal to one BM and a DC signal to another, the polarization states of the output light are modulated to cover the entire surface of the Poincaré sphere.

Fabrication and characterization of hollow metal waveguides for optical interconnect applications

As data rates continue to increase in high-performance computer systems and networks, it is becoming more difficult for copper-based interconnects to keep pace. An alternative approach to meet these requirements is to move to optical-based interconnect technologies which offer a number of advantages over the legacy copper-based solutions. In order to meet the stringent requirements of high performance and low cost, manufacturable waveguide technologies must be developed. Past solutions have often employed polymer waveguide technologies, which can be expensive and limited by modal dispersion. In the present work, hollow metal waveguides (HMWGs) are investigated as a potential alternative. These waveguides demonstrate very low optical losses of <0.05 dB/cm and the capability to transmit at extremely high data rates. The fabrication, modeling, characterization of the HMWGs are discussed to enable photonic interconnect solutions for future generations of computer and server products.

High-performance polymeric componentry for telecom and datacom applications

We review a polymeric waveguide technology developed to produce affordable high-performance optical components that address the needs of both the telecom and the datacom industries. We engineer advanced organic polymers that can be readily made into planar single- mode, multimode, and micro-optical waveguide structures of controlled numerical apertures and geometries. These materials are formed from highly crosslinked acrylate monomers with specific linkages that deter- mine properties such as flexibility, toughness, optical loss, and environ- mental stability. These monomers are intermiscible, providing for precise continuous adjustment of the refractive index over a wide range. In poly- mer form, they exhibit state-of-the-art loss values, suppressed polariza- tion effects, and exceptional stability, enabling their use in a variety of demanding applications. Waveguides are formed photolithographically, with the liquid monomer mixture polymerizing upon illumination in the UV via either mask exposure or laser direct writing. A wide range of rigid and flexible substrates can be used. The devices we describe include a va- riety of passive and thermo-optically active elements that achieve a va- riety of coupling, routing, and filtering functionalities. These devices can be either individually pigtailed and packaged components or they can be part of a massively parallel photonic integrated circuit on the multichip module (MCM), board, or backplane level. © 2000 Society of Photo-Optical Instrumentation Engineers. (S0091-3286(00)01003-5)

Polymer-waveguide-based photonic switch

Polymer waveguide technology was exploited to build a photonic switch with enormous bandwidth capabilities at extremely low cost per path. The properties of polymer waveguides allowed the use of a low-cost multielement spatial light modulator in a guided wave application. A 6 x 6 ferroelectric liquid crystal array was used as a switching element to block or transmit light signals between input and output fibers. Visible laser diodes, plastic fibers, PIN detectors, and our proprietary polymeric mixing rod couplers were used to construct the switch. The polymeric fibers, couplers, and switching element allowed eliminating the need to time-division multiplex photonic channels through the switch because the optical paths were no longer costly. This, in turn, eliminated the electronic buffering and synchronization requirements of the switch. This is critical, because signals that can be buffered and synchronized can be switched electronically using GaAs cross-point arrays. Although data-transparent wavelength conversion is acceptable at the inputs and outputs of a photonic switch, buffering and synchronization are not acceptable for some applications. Our low cost polymer waveguide approach also eliminates the need for costly multi-GHz lasers when they are not needed on a per channel basis.