Packaging requirements for integrated optics components

Gary C. BjorklundChief Technology OfficerNanovation Technologies, Inc.47050 Five Mile RoadNorthville, MI 48167INTRODUCTIONLow cost, reliable packaging that meets essential performance requirements is key tofuture wide-spread applications of future of planar waveguide integrated opticscomponents. Currently, such integrated optics components are being fabricated using awide variety of design parameters and materials that dictate the optimum packagingapproach to be used in each case. However, there are certain universal packaging issuesthat must be addressed to some degree for all types of integrated optics. These aremechanical support, environmental protection, thermal control, electrical connection, andoptical connection. Most applications, particularly those in the telecommunicationsarena, require that the entire package stand up to wide temperature excursions, humidity,and mechanical shock and vibration.Mechanical support includes providing a housing within which the integrated opticalchip, associated thermal control apparatus, and integrated drive electronics can besecurely mounted. The housing must also provide mechanical support for multipleelectrical leads and connectors as well as multiple input and output optical fibers. It alsobe capable ofbeing mounted to the standard printed circuit boards that comprise currentand future photonic systems and should have a form factor compatible with close boardto board spacing.Environmental protection that must be provided by the package includes protection ofsensitive components from moisture, and from other water or airborne chemicals withdeleterious effects. These deleterious effects include corrosion, damage to surfacecoatings, degradation of optical transparency, and degradation of electrical isolation.Thermal control is a difficult problem, since many wavelength selective integrated opticscomponents such as distributed feedback diode lasers, unbalanced Mach Zehnderinterferometers and arrayed waveguide gratings (AWGs) have spectral characteristicsthat are sensitive functions of temperature. Active temperature stabilization to a fractionof a degree must be provided, usually by incorporating thermo-electric cooling/heatingelements in the package. The issue is exacerbated by the fact that integrated opticaldevices such as diode lasers, semiconductor optical amplifiers, and thermo-optic switchesgenerate amounts ofheat within the package that must be removed without disturbing thethermal control of the temperature sensitive elements.Except for totally passive integrated optical circuits, such as splitters, that do not requiretemperature control, the package must provide electrical connections. Low frequency