Abstract: The optical fiber-based communication system comprises a distribution optical fiber that extends proximately to a plurality of end users, and tap-off modules coupled to the distribution optical fiber at intervals along its length. Each of the tap-off modules includes a port in optical communication with the distribution optical fiber. The optical fiber-based communication system additionally comprises a branch optical fiber connected to the port of each of at least some of the tap-off modules and that extends to a corresponding one of the end users.

Abstract: A photodiode array includes a plurality of arrayed individual diode devices. The arrayed diode devices include at least one active photodiode and at least one reference diode. A bias control circuit for the array monitors operation of the reference diode at an applied first bias voltage and adjusts that applied first bias voltage until optimal reference diode operation is reached. A second bias voltage having predetermined relationship to the first bias voltage is applied to the active photodiode to optimally configure array operation. More specifically, an operational characteristic of the reference diode at the first bias voltage is monitored and compared to a reference value. As a result of this comparison, the circuit adjusts the applied first and second bias voltage in order to drive the reference diode measured characteristic to substantially match the reference value.

Abstract: A process for discovering a path from a source node to a destination node through a network by using “collisions” of randomly-propagating “feeler” packets originating from both the source node and the destination node. A discovered path is reported to the source node by the collision-detecting node where it may be stored and updated responsively to reports of new feeler packet collisions. Paths discovered and reported may be analyzed at either the collision-detecting node or the originating node to remove loops. The random collision-detecting path-discovery procedure reduces the operational traffic overhead associated with other exponentially-proliferating discovery methods. The feeler packets are propagated randomly through the network topology, thereby imposing relatively uniform path-discovery traffic effects in the network. Path discoveries arising from feeler-packet collisions always reflect current network topology and traffic conditions.

Abstract: A planar array of lenses are configured and independently translatable along in-plane X and Y axes by corresponding MEMS actuators such that a light beam emanating from the facet of a first selected optical fiber in an adjacent bundle of fibers can be deflected in a first predetermined manner by a first one of the lenses, reflected off of an adjacent co-planar mirror back to the array of lenses, and deflected in a second predetermined manner by a second one of the lenses and focused on the facet of a selected second optical fiber in the bundle. In an alternate embodiment, the planar mirror is replaced with a second array of MEMS actuated lenses so that light pulses from a selected optical fiber in an input bundle can be steered to a selected optical fiber in an output bundle.

Abstract: In a 3D MEMS optical switch titling mirrors are actively aligned to minimize losses in optical power. In one embodiment the optical signals in the output fibers are tapped and detected and the sensed outputs are used by a control circuit with a feedback loop that adjusts the alignment signals sent to the MEMS actuators. In a second embodiment, an emitter which is either a single LED or laser diode is optically coupled to the output fibers for injecting alignment beams back into the fibers. The alignment beams have a frequency bandwidth outside that of the information beams. The alignment beams are detected at the input fibers via directional optical couplers and the sensed outputs are used by a control circuit with a feedback loop to adjust the alignment signals. The alignment signals are dithered and their phase and amplitude shifts are used to generate the appropriate feedback signals.

Abstract: A first plurality of stages each support a ferrule surrounding an end portion of a corresponding one of N optical input fibers. A second plurality of stages each support a ferrule surrounding an end portion of a corresponding one of M optical output fibers. Mechanical mechanisms translate the stages along a plurality of orthogonal X and Y axes to align a facet of a selected one of the N input optical fibers with a facet of a selected one of the M output optical fibers. The stages of the input optical fibers, the output optical fibers, or both, have mechanical mechanisms for moving the ferrules along Z axes perpendicular to the X and Y axes into and out of alignment holes of a central panel to physically mate the facets of the coupled fibers.

Abstract: An array of n-wavelength vertical cavity surface emitting lasers (VCSELs) can be grown with precise and repeatable wavelength control. First, a foundation VCSEL structure is grown on a substrate. Next, n-paired layers of AlGaAs and InGaP are grown, where n is the desired number of different wavelengths. Next, one of the n regions is masked and etched. The steps of masking and etching are repeated until all n regions are etched. Finally, the upper VCSEL structure is grown.

Abstract: A demultiplexer includes a unitary optically transparent structure that utilizes focusing relay mirrors to relay a multi-wavelength beam of light among a series of wavelength-specific interference filters, with each filter separating out a specific wavelength component from the multi-wavelength beam. The relay mirrors are focusing mirrors, so that the demultiplexer can be operated with a non-collimated light beam in a manner that controls the potentially large angle of divergence of non-collimated light, while taking advantage of the small beam diameter in order to create a demultiplexer with greater miniaturization.

Abstract: An array of n-wavelength vertical cavity surface emitting lasers (VCSELs) can be grown with precise and repeatable wavelength control. First, a foundation VCSEL structure is grown on a substrate. Next, n-paired layers of AlGaAs and InGaP are grown, where n is the desired number of different wavelengths. Next, one of the n regions is masked and etched. The steps of masking and etching are repeated until all n regions are etched. Finally, the upper VCSEL structure is grown.

Abstract: A zigzag waveguide device is described that includes at least two optical waveguides converged at a vertex to form a waveguide overlap region. Optical loss in the waveguide overlap region is minimized by including a narrow gap of lower refractive index between the overlap region and each waveguide. This technique is also applied to minimize loss in a region where two optical waveguides cross one another. A mirror or optical filter reflectively couples the two waveguides at the vertex. When the coupling is provided by an optical filter, some range of wavelengths is transmitted out of the zigzag waveguide device, rather than reflected. The transmitted light may be collected by an output waveguide which is wider than the waveguides to minimize loss due to divergence. Light exiting the device may be coupled directly to a photodetector with no intervening optical fiber. In addition, the width of an input waveguide of the zigzag waveguide device is tapered to reduce angular spread of the light in the zigzag device.