Abstract: A method for controlling the frequency dependence of insertion loss in an etalon-lens-fiber (ELF) optical assembly comprises defining target frequencies and insertion loss objectives therefor and adjusting the optical path length between pairs of the etalon, lens and fiber components until insertion loss objectives are achieved. Insertion loss objectives include insertion loss and insertion loss ripple objectives. The method allows for control of the frequency dependence of insertion loss and insertion loss ripple without introducing additional components, such as spectral filters, into the system.

Abstract: A chromatic dispersion compensator comprises a beam delay element, such as one or more Gires-Tournois etalon (GTEs); a beam director, such as a polarizing beam splitter (PBS), a prism polarizer, a dielectric polarizer or a crystal polarizer; and a polarization changer, such as one or more quarter-wave plates. The beam director directs an inbound optical beam based on its polarization toward the beam delay element whereat a first unit of group delay is induced. The optical beam traverses the beam delay element and enters a polarization changer whereat the optical beam obtains a new polarization. The optical beam traverses the polarization changer and re-enters the beam director whereupon a path change is induced on the optical beam based on its new polarization and the optical beam is redirected toward the beam delay element whereat a second unit of group delay is induced.

Abstract: A spectral interleaver providing flat top spectral transmission passbands and athermal operation is disclosed. The spectral interleaver may comprise a pentagon-shaped birefringent crystal, a polarization beam splitter, and a dielectric mirror at one facet of the crystal. Prisms and polarizing beam splitters can be employed for operation with an unpolarized input beam. The cavity formed by the mirror and the crystal serves as a spectrally dispersive mirror. Front mirror reflectivity is provided by the air-crystal (or other medium-crystal) interface. Proper mirror reflectivities can be achieved by selecting the angle ? of the pentagon-shape crystal. By selecting the proper air space between the mirror and the crystal surface and the crystal length, the interleaver can have a flat top transmission function. A combination of two different crystals which exhibit different thermal-optic effects may be employed such that the total phase retardation is independent of the temperature, leading to athermal operation.

Abstract: An optical assembly includes a fiber optic pigtail, a sleeve in which the pigtail is housed, a collimating lens, a rod upon which is mounted an optical device and a lens sleeve in which the lens and rod are housed. Bonding lines bond the rod and lens to the lens sleeve, the pigtail to the pigtail sleeve, and the pigtail sleeve to the lens sleeve. The optical assembly and method of fabrication thereof support multiple optical device geometries, longitudinal adjustment of the position of the optical device within the optical assembly, an extended bonding line between the optical device and the environment outside the optical assembly, full x-y-z positioning of the pigtail relative to the lens and reduced reliance on bonding line thickness irregularities.

Abstract: “Per memory” atomic access for a distributed memory multiprocessor architecture is provided by marking bit masks for shared memories to indicate the access privileges of processors to the memories. A processor has access privileges to a shared memory if the bit mask retained for the memory is marked at a bit position reserved for the processor and does not have access privileges if the bit mask is not so marked. A bit mask is permitted to have only one mark at a given time to guarantee that access to each shared memory is atomic.

Abstract: A user authentication service for a communication network authenticates local users before granting them access to personalized sets of network resources. Authentication agents on intelligent edge devices present users of associated end systems with log-in challenges. Information supplied by the users is forwarded to an authentication server for verification. If successfully verified, the authentication server returns to the agents authorized connectivity information and time restrictions for the particular authenticated users. The agents use the information to establish rules for filtering and forwarding network traffic originating from or destined for particular authenticated users during authorized time periods. An enhanced authentication server may be engaged if additional security is desired. The authorized connectivity information preferably includes identifiers of one or more virtual local area networks active in the network.

Abstract: A switching device for forwarding network traffic to a desired destination on a network, such as a telephone or computer network. The switching device includes multiple ports and uses a lookup table to determine which port to forward network traffic over. The lookup table includes network addresses that are maintained in ascending or descending order. The switching device includes multiple binary search engines coupled in series including one or more precursor binary search engines and a final stage binary search engine. Together, the binary search engines perform an N iteration binary search. Additionally, a single search engine can perform multiple concurrent searches so that source and destination addresses can be obtained simultaneously and without wasted memory cycles.

Abstract: A method and apparatus for switching/bridging frames between a heterogeneous media is disclosed. Bridges and/or switches normally bit-swap a MAC header of a frame when switching the frame between heterogeneous media. However, this practice introduces errors in address formats in certain situations. Such problems are resolved by investigating whether a frame to be switched includes local address components, and if so, these address components in the frame are manipulated to ensure that the address formats are proper for a media onto which the frame is being switched.

Abstract: An equalization device has a digital equalizer for joint tuning of a data-carrying signal distorted by analog transmission. The digital equalizer includes a closed-loop automatic gain control (AGC) circuit for applying a compensatory frequency-independent gain to the distorted signal followed by a frequency filter for applying a compensatory frequency-dependent gain to the signal. Joint tuning produces an output signal which more closely resembles the originally transmitted signal, facilitating recovery of implicit clock and more reliable data recovery. The digital equalizer may be advantageously stage-implemented as a preliminary digital equalizer which is preceded by an analog equalizer and followed by a final digital equalizer.