Finisar

Abstract: An information broadcasting system provides a large number of subscribers access to a large amount of information using one or more satellite transmission channels. The system can also use cable television transmission channels. A program supplier station stores an information database and tags all the information in the database with indices so as to form a single hierarchical structure which encompasses the entire information database. Portions of the information database are transmitted often, at least once per day, in order to provide the basic subscriber with information need to access the remainder of the database. The information provided by the basic subscriber service, which will typically include at least 50 gigabytes of data, is available to all subscribers without requiring two way communications between the subscribers and the program supplier station. Using a tiered system for scheduling transmission of the 50 gigabytes or so of information included in the basic subscriber service, as well as an intelligent subscriber request anticipation scheme for retrieving information before the subscriber asks for it, the present invention provides subscribers with reasonably quick access to all the contents of the large database while using only a modest amount of bandwidth. Furthermore, by reserving a portion of the system's bandwidth for satisfying requests for access to information not provided with the basic subscriber service, timely access to a virtually unlimited amount of information can be provided, using the same modest transmission bandwidth, to those subscribers willing to pay additional fees for that service.

Abstract: The vast majority of optical links within the data center are based on vertical cavity surface emitting lasers (VCSELs) operating at 850 nm over multimode optical fiber. Deployable links have evolved in speed from 1 Gb/s in 1996 to 28 Gb/s in 2014. Serial data links at 40 and 56 Gb/s are now under development and place even more demand on the VCSEL and photodiodes. In this paper, we present the characteristics of VCSELs and photodiodes used in current generation 28 Gb/s links and present several methods to extend link distances using more advanced data encoding schemes. Finally, we will present results on wavelength division multiplexing on multimode optical fiber that demonstrate 40 Gb/s Ethernet connections up to 300 m on duplex OM3 optical fiber, and present results on fiber optimized for modal bandwidth in the 850 to 980 nm range.

Abstract: A laser diode controller (102) uses a programmed microcontroller (162) to accurately control the process of turning on and selecting the operating point of the laser diode (100). The laser diode (100) has a front facet (110) for transmitting light, and a back facet (114) for monitoring the laser diode's optical output power. Once the back facet (114) of the laser diode (100) is calibrated, the controller can accurately monitor the laser diode's operating characteristics, and can select the best operating point current based on the current operating characteristics of the laser diode (100). During calibration of the laser diode (100), the controller (102) can check the linearity of the laser diode's optical output power as a function of drive current, and can thereby detect defects in the laser diode (100). In a full duplex optical link, the controller (102) of the present invention prevents the laser diodes from generating light at their full normal intensity until the integrity of the link has been established, thereby preventing light from the laser diode's from accidentally damaging user's eyes. Furthermore, the controller (102) can use the full duplex link to establish lower operating point drive currents that would otherwise be used, thereby significantly lengthening the lifetime of the laser diodes (100). A laser diode's operating characteristics change over time in such a way as to enable the controller (102) to predict when the laser will fail. The controller (102) records the operating characteristics of the laser diode (100) in a nonvolatile memory, analyzes changes in those characteristics, and generates a failure warning message when those changes match predefined failure prediction criteria.

Abstract: Secure point to point network communications. Secure point to point network communications are accomplished by sending data across a secure link. Trusted partners at the link are matched to each other. To ensure that no un-trusted partners are on the link, authentication is performed. One of the points may be a secure tap. The secure tap authenticates a trusted partner by receiving a hardware embedded encryption key or value derived from the hardware embedded encryption key from the trusted partner. Data sent on the trusted link is encrypted to prevent interception of the data. The secure tap polices the link to ensure that no un-trusted are attached to the link and that the trusted partner is not removed from the link. If un-trusted partners are added to the link or trusted partners removed from the link, the secure tap ceases sending data.