The demands of exponentially growing Internet traffic, coupled with the advent of Dense Wavelength Division Multiplexing (DWDM) fiber optic systems to meet those demands, have triggered a revolution in the telecommunications industry. This dramatic change has been built upon, and has driven, improvements in fiber optic component technology. The next generation of systems for the all optical network will require higher performance components coupled with dramatically lower costs. One approach to achieve significantly lower costs per function is to employ Planar Lightwave Circuits (PLC) to integrate multiple optical functions in a single package. PLCs are optical circuits laid out on a silicon wafer, and are made using tools and techniques developed to extremely high levels by the semi-conductor industry. In this way multiple components can be fabricated and interconnected at once, significantly reducing both the manufacturing and the packaging/assembly costs. Currently, the predominant commercial application of PLC technology is arrayed-waveguide gratings (AWG's) for multiplexing and demultiplexing multiple wavelength channels in a DWDM system. Although this is generally perceived as a single-function device, it can be performing the function of more than 100 discrete fiber-optic components and already represents a considerable degree of integration. Furthermore, programmable functions such as variable-optical attenuators (VOAs) and switches made with compatible PLC technology are now moving into commercial production. In this paper, we present results on the integration of active and passive functions together using PLC technology, e.g. a 40 channel AWG multiplexer with 40 individually controllable VOAs.
Fiber-optic switches are becoming increasingly important for fiber management, restoration and provisioning applications in dense wavelength division multiplexed (DWDM) long distance telecom networks. Specific applications for optical switches include optical crossconnects and optical add/drop multiplexers.
BeamBox polymer based fiber-optic space switches have been submitted to a reliability qualification program. The results of this program show that these switches meet the requirements for telecommunication applications. Highly stable switches have been obtained by proper design, testing, and optimization of materials, parts, and production processes.
Planar polymer waveguide technologies have shown the promise for applications in multi-port modulation and switching systems. We describe a key application of electro-optic polymer waveguides to modulator arrays and then illustrate the state-of-the-art performance obtained with our lxN thermo-optic switches.
Electro-optic (EO) poled polymer materials exhibit low dispersion and low dielectric constants. EO polymer materials have been modulated flat to 40 GHz and exhibit few fundamental limits for ultrafast modulation and switching. Channel waveguides and integrated optic circuits can be defined by the poling process itself, by photochemistry of the EO polymer, or by a variety of well understood micro-machining techniques. EO polymer materials have been used to fabricate high-speed Mach-Zehnder modulators, directional couplers, Fabry-Perot etalons, and even multi-tap devices. Practical issues remain to be solved before polymer photonic technology may be exploited in systems such as datacom and telecom. These include reliable, low cost fiber-attach and packaging, support circuitry and interfaces, and the scale-up to high volume production. This talk reviews requirements for practical exploitation and displays recent progress toward achieving reliable products.
Electro-optic polymer waveguide modulators may be used in parallel external modulation arrays supplied by branching structures providing fanout from a cw laser for a variety of applications, including CATV and data communications. This paper highlights some of the benefits of using EO polymer modulators in arrays for point-to-point digital data communications.
Electro-optic polymer waveguide modulators may be used in parallel modulation arrays supplied by branching structures providing fanout from a CW laser for a variety of applications, including CATV and data communications. This paper highlights some of the benefits of using EO polymer modulators in arrays for point-to-point digital data communications.
An approach to optical interconnect networks at the module level is presented that addresses the requirements imposed by electronic system manufacturing, such as thermal stability, low cost, and compatibility with standard electronic design, fabrication, and assembly processes. Research is presented on poled polyimide electro-optic materials with extended thermal stability, poled polyimide integrated optic switches acting as transmitters, and a demonstration of a CMOS-compatible optical interconnect.
We report the background leading to the development of the first all-polyimide system (cladding/core/cladding) suitable for fabrication of electro-optic waveguide devices on silicon substrates. The cladding layers are spun from a low optical loss, commercially available polyimide that is suitable for multilayer stacks. The electro-optic material consists of this same polyimide as host to a commercially available guest chromophore and is based upon our prior work on thermoplastic polyimides. The synthesis and purification of this chromophore and an analog is discussed. We also present the materials and process development methodology with the results for this polymer system and demonstrate it by fabrication of an all-polyimide Mach- Zehnder modulator operating at 830 nm. CMOS-compatible switching using a device based on the new material has been demonstrated.
The exceptional electro-optic properties of poled polymer films, coupled with the power and flexibility of thin film fabrication and photolithographic processing, may make possible the hybrid integration of electronic and photonic devices, combining the processing power of VLSI with a dense, high bandwidth, photonic interconnection and switching network in a single, large format, package. In this paper, we describe the potential applications and benefits of electro-optic polymers for optical interconnection and present a review of some of the relevant progress to date in electro-optic polymer materials and devices. Development of an all-polyimide electro-optic polymer system (cladding/core/cladding) based entirely on commercially available components is described. An integrated optic Mach-Zehnder modulator was fabricated using this material system and used in a 200 Mbit/sec digital signal transmission optical interconnection demonstration. Lastly, a potential increase in electro-optic polymer integration density was illustrated by a proof of concept demonstration of three levels of waveguide structures on a single substrate.
Using polyimide as host in a guest-host electro-optic thin film a thermally stable poled electro- optic response is demonstrated at temperatures at 150 degree(s)C and 300 degree(s)C. A coplanar-electrode poling geometry is used so that the guest molecular alignment between the electrodes is coincident with the free volume of the host. Electric field poling during curing process including imidization (170 - 230 degree(s)C) and densification (340 - 380 degree(s)C) accounts for the highly thermally stable electro-optic response.
The exceptional electro-optic properties of poled polymer films, coupled with the power and flexibility of thin film fabrication and photolithographic processing, may make possible a new class of integrated optic systems: photonic large scale integration (PLSI). PLSI systems are characterized by the hybrid integration of electronic and photonic devices, combining the processing power of VLSI with a dense, high bandwidth, photonic interconnection and switching network in a single, large format, package. In this paper, we describe the potential applications and benefits of PLSI and present a review of some of the relevant progress to date in electro-optic polymer materials and devices, including the demonstration of polymer switch based 100 Mbit/sec digital signal transmission for optical interconnection and a 20 GHz electro-optic polymer modulator.
Electro-optic polymers exhibit many useful properties for distribution and routing of light on optical multilayer boards and modules. With the development of more robust materials it should soon be possible to use these materials to provide high-density interconnects at significant power savings and with reduced noise at frequencies above 100 MHz. We review the research toward creating new materials and devices for applications to packaging technology.
We report on the recent development and initial test results of two electro-optic polymer based integrated optic devices for
optical interconnection applications. The first is an optical railtap for the distribution of many different optical signals from a
single CW laser diode, and the second is a traveling wave Mach-Zehnder integrated optic modulator, which was modulated at
frequencies up to 8 GHz. Electro-optic polymer materials supplied by Akzo Research, By, were used in both devices.
Glassy nonlinear optical polymers can be processed into channel waveguides. When poled, the channels become electrooptic and can switch and modulate light. Using lithographic and machining techniques familiar to the chip industry, it should be possible to integrate large numbers of electrooptic switches into a board-level package or module, and thus provide the additional benefits of active switching and reconfiguration to passive hybrid optical interconnect modules. Some of the properties of the materials, some process methods, and potential applications in optical interconnection are described.