Harsh environments create unique challenges for fiber optics and especially for original equipment manufacturers, who want to limit the traditional conditions associated with fiber systems.
As a major suppler of fiber optic solution sets since 1983, Tyco Electronics has often been called upon to resolve many difficult design issues pertaining to the reliability and serviceability of optic systems for customers.
Applications in industries such as aerospace (air, land, and sea), digital cinema, geophysical research, and controllers used in industrial equipment require a different approach to optic system design. Successful deployment of optics in these harsh environments calls for components specifically designed to meet these needs.
The "crucial" components for these solution sets are often the interface component or the panel Input Output device (connectors) and the fiber management to make the optic assembly resilient and serviceable in these applications. Typical operating temperature ranges are from -50 to +125 degree C in "harsh" environs to -40 to +85 deg C for the "industrial" applications. High shock, long-term vibration, high humidity, and dirt / dust ingress all pose difficult challenges in the design and deployment of reliable optical solutions.
Some examples of complex optical assemblies and interconnects are depicted below with comments on their application and how they solve a particular challenge.
Control box design VME chassis.
Application: Board to board interfaces.
VME based "P Zero" connectors as well as other daughter / motherboard interface designs deliver increased functionality for the control board user.
To better protect the optic interface in a harsh environment, a protective glass ball lens insert can be placed in front the fiber face. The Ball Lens is hardened and coated to better withstand attack from environmental hazards such as solvents or gases. The Ball Lens expands the optic beam, providing greater resiliency to dirt or debris trapped within the connector interface. The beam is also collimated -- this allows an air gap between connectors. Dirt and debris are not trapped between the fiber end faces. Mating traditional physical contact fiber connectors with dirt trapped on fiber end faces often results in malfunctions.
This is done by packaging up to four fibers per circular module in two positions at the backplane and motherboard interface. This system provides a nominal .7db insertion loss over the service life of this design.
Blind Mating optics. Rack Mounted with intermediate interface to remote box.
Application: In Flight entertainment, Commercial Aircraft Network, Network Controllers in Factory environment linking to Building WAN.
Some users have experienced downtime and costly maintenance when using blind mating optics. The predominant concern is dirt, dust, and transient impurities, especially when working with single mode interfaces. Traditional fiber optic connectors must be cleaned and inspected prior to mating. This is often very difficult with this type of application. A more reasonable design considers these contaminants and adapts the design to be more resistant to the detrimental effects.
Traditional data communication and telecommunication fiber optic systems have been developed with controlled environments and specific installation and maintenance practices. Equipment rooms, for example, are often supplied with specific HVAC systems regulating the operating temperature of the enclosed electronics. Common practice in these environments calls for careful cleaning and inspection of optic interfaces upon each and every mating cycle.
As networks extend to operations that include uncontrolled environments such as machinery, controls, and other industrial support equipment / communications paths, deployment requires that optical equipment conform to the operating conditions that these new environments present. It is unreasonable to expect these industries to adopt practices used in commercial/telecom industries. Equipment and components must therefore change and adapt for service in harsh environments.
Designing in greater reliability for these systems is the key to success. Components and systems are chosen for their resistance to harsh environmental conditions, rather than employing commercial components and trying to impose unworkable operating practices and environments for their successful operation.