Abstract: An optical amplifier system for amplifying an input wavelength division multiplexed (WDM) optical signal with a first optical coupler to extract a portion of the power of the input signal, an erbium-doped fiber amplifier to generate an output signal and a second optical coupler to extract a portion of the power of the output signal. A spectral monitoring unit having a volume phase grating separates the extracted input and output signals into spectral components. A photo-detector array of the spectral monitoring unit determines the power level of the spectral components. The system further includes a controller operative to control the operation of the amplifier in response to the power levels of the spectral components.

Abstract: An optical amplifier system for amplifying an input wavelength division multiplexed (WDM) optical signal with a first optical coupler to extract a portion of the power of the input signal, an erbium-doped fiber amplifier to generate an output signal and a second optical coupler to extract a portion of the power of the output signal. A spectral monitoring unit having a volume phase grating separates the extracted input and output signals into spectral components. A photo-detector array of the spectral monitoring unit determines the power level of the spectral components. The system further includes a controller operative to control the operation of the amplifier in response to the power levels of the spectral components.

Abstract: An optical signal receiver has an increased dynamic range for detecting optical signals whose intensity varies over a wide range. In one embodiment, the optical signal receiver includes a circuit operable to provide a reverse bias voltage and an avalanche photo-diode (APD) coupled to the circuit to receive the reverse bias voltage. The circuit is operable to lower the reverse bias voltage in response to an increase in power of the received optical signals. Since the current gain of the APD is a function of the reverse bias voltage, the circuit indirectly lowers the current gain of the APD in response to the increase in power of the received optical signals. As a result, the optical signal receiver can be used to detect optical signals whose intensity varies over a broad range.

Abstract: A Cable Television (CATV) digital return link system that provides dedicated, high-speed, full-duplex and point-to-point connections between users and the head end system is disclosed. The CATV digital return link system includes return path transmitters, intermediate hubs and a head end hub coupled to each other via a network of fiber optics cables. The return path transmitters are each coupled to a relatively large number of users via a local CATV-subtree. Signals from cable modems are transmitted via the local CATV-subtree to the return path transmitters for transmission to the head end. A number of users are individually and directly connected to the return path transmitters. Data from these directly connected users is transmitted to the head end via the network of fiber optics cables in conjunction with the RF data from the subtree. Likewise, data from the head end to these directly connected users is transmitted in the forward path direction using the digital return link system.

Abstract: An optoelectronic device that has a network address (e.g., IP address) and participates in in-band traffic for purposes of performing functions (e.g., network diagnostics, network control, network provisioning, fault isolation, etc.) that are traditionally performed by host equipment. An embodiment of the invention may have a protocol engine and a status monitoring module. The protocol engine identifies data packets that are addressed to the optoelectronic device, and allows the optoelectronic device to insert packets of information generated by the device into in-band data. Logic of the optoelectronic device may modify the operating parameters of the device according to the control information included in the data packets. The status monitoring module detects the device's physical conditions and the conditions of its links.

Abstract: An optical signal return path system includes a transmitter having a sample clock generator for generating a sample clock and an RF signal receiver for receiving and converting an analog RF data signal into a first data stream of digitized RF data samples at a rate determined by the sample clock. Supplemental channel circuitry provides a second data stream. A multiplexor receives and combines the first data stream and second data stream, and an optical transmitter converting the combined data stream into a serialized optical data signal for transmission over an optical fiber. The second data stream may contain maintenance data reflecting an operational state of the transmitter. A receiver receives the optical data signal and recovers therefrom a digital data stream and an associated first clock having an associated first clock rate. The data stream is stored in a memory device at the first clock rate.

Abstract: A dual optical fiber transceiver, for use with first and second optical fibers, includes a laser transmitter for transmitting laser light into the first optical fiber, a laser light receiver for receiving laser light from the second optical fiber, and a controller coupled to the laser transmitter and laser light receiver. The controller includes a multi-protocol state machine for establishing the full duplex connection whenever the other device operates in compliance with either (A) a predefined "on-off-on" signaling protocol for establishing full duplex connections, or (B) a second predefined signaling protocol for establishing full duplex connections. In a preferred embodiment, the predefined "on-off-on" signaling protocol is the Open Fiber Control (OFC) protocol and the second predefined signaling protocol is a standard "laser transmitter always on" protocol.

Abstract: The present invention provides an improvement in circuit switching for a network comprising a switching apparatus including a plurality of transceivers for interfacing directly with a like plurality of nodes. Each of the transceivers has a receive and transmit through port for passing data to and from nodes. Transmitted data includes a connect/disconnect sequence, a first wait sequence, and user data. The switching apparatus further includes circuitry for isolating each transceiver so as to loop back data when not in use and a switching matrix for directly connecting any pair of transceivers. Each of the transceivers includes circuitry for detecting a connect and disconnect sequence and an interface for connection to a serial asynchronous receiver to derive node requests, routing data, priority and other information from the connect sequence detected at the transceiver.

Abstract: The present invention provides a an improvement in circuit switching for a network comprising a switching apparatus having a plurality of transceivers for interfacing directly with a like plurality of user nodes. Each of the transceivers having a receive and transmit through port for passing data to and from user nodes and a network, said data comprising a connect sequence, a first wait sequence, a routing packet, a second wait sequence, user data, and a disconnect sequence. The switching apparatus further includes means for isolating each transceiver to loop back data when not in use and switching means for directly connecting any pair of transceivers. Finally a switch controller is provided for establishing and prioritizing matrix connections and disconnections, and decoding routing packets.

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.

Abstract: Two (2) optical fibers each having a core, a cladding enveloping the core and a buffer enveloping the cladding are spliced. First and second positions are adjacent the first fiber and third and fourth positions are adjacent the second fiber. The second and third positions are respectively closer to the splice than the first and fourth positions. Light emitters are at the first and fourth positions and light detectors are at the other positions. Light from each emitter is selectively passed to individual ones of the detectors. Members (e.g. solid gels) adjacent the emitters direct light into the associated fibers. Other members (e.g. solid gels) respectively between the first and second positions and between the third and fourth positions inhibit the light passage in the fiber claddings and buffers so that only the light in the fiber cores passes to the detectors. The gels and the fibers are clamped to provide matching dimples for trapping in the gels the light in the claddings and buffers.

Abstract: A light mixing device includes multiple light sources supplying light into a mixing rod. The mixing rod mixes the light and supplies it to a plurality of output optical fibers. The physical configuration of the mixing rod is such that light from the various light sources is coupled to each of the output fibers in such a fashion that the light carried by each of the fibers is relatively equal in intensity. The mixing rod structure is larger than the diameter of a single fiber to enable coupling light into multiple fibers. The illumination sources disclosed are narrow-band light emitting diodes wherein light having a narrow frequency range is produced by each LED. Multiple LEDs producing light in several distinct ranges are used.

Abstract: A fiber optic transmitter circuit includes a DC bias circuit that produces a DC voltage, an amplifier circuit having data signal inputs and that produces a data signal and wherein the data signal and the DC voltage are supplied to a laser diode to stimulate the diode to produce light of a corresponding nature. The amplifier is selected so that the inherent noise level or noise figure characteristics of the amplifier are such as to provide stimulation of a single mode laser diode in the frequency band wherein the resonant frequency of the laser diode is typically found. The resulting impact of the noise on the laser diode is to transform the single mode laser diode into a multi-mode laser diode thereby reducing the impact of modal noise on the fiber optic data transmission system that incorporates the disclosed fiber optic transmitter device.

Abstract: An apparatus for terminating an optical fiber includes a resiliently deformable spherical member disposed in contact with a front end of a bore of an optical fiber contact body. Subsequent to softening an adhesive disposed within the contact body bore, an optical fiber is inserted through the bore and the adhesive until the fiber contacts the blocking member and deforms it. The resiliency of the blocking member causes adhesive to be wiped off the front face of the fiber being terminated and into an annulus formed between an outer cylindrical surface of the fiber and an inner cylindrical surface of the bore, and causes the fiber front end to be recessed a predetermined amount from a front end of the contact body.

Abstract: A laser diode controller uses a programmed microcontroller to accurately control the process of turning on and selecting the operating point of the laser diode. The laser diode has a front facet for transmitting light, and a back facet for monitoring the laser diode's optical output power. Once the back facet of the laser diode 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. During calibration of the laser diode, the controller 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.

Abstract: A bus receiver communicates with a bus head end transmitter via a communication path different from read and write optical fibers used by a plurality of remote terminals on the bus so that the bus receiver can quickly determine beginning and end of time slots, clock frequency, and signal trigger levels using a minimum amount of bits attached to a front end of each packet in each time slot.

Abstract: An optical switch channels incoming light to selected transmission elements. The switch includes a GRIN lens having two opposite surfaces, one of which has a mirror coating applied to it. At least four optical transmission elements, typically optical fibers, are connected to the non-mirrored surface of the lens. When used in an optical signal networking application, one of the four transmission elements couples the switch to a node's receiver and another couples the switch to a node's transmitter. The remaining two transmission elements, called in the input line and the output line, attach the node to the network and thereby conduct light from the previous node to the device or conduct light from the device to the next node on the network. The transmission elements and the lens element move with respect to each other into one of two possible states, called the bypass and active states.

Abstract: Forming an optical fiber so as to have a relatively constant bend loss characteristic includes apparatus for continuously bending the optical fiber downstream from a preform from which it is drawn and continuously detecting light withdrawn from the fiber at the bend so created to determine the fiber bend loss characteristic, the fiber bend loss characteristic being maintained constant by using feedback control to vary a drawing speed of the fiber and hence a diameter of a core of the fiber.

Abstract: An optical fiber tap for connecting polymer optical fibers is achieved by heating an end section of the fibers to be connected and deforming the end sections into a non-circular cross-sectional shape so as to form a throughput cross-sectional area and a add/drop throughput area, the optical fiber ends being thereafter aligned so as to allow for efficient signal extraction and injection.

Abstract: An optical fiber contact for terminating an optical fiber includes a solid multi-part thermoset mixture in a cavity in a front portion of the contact, an optical fiber being terminated by heating the thermoset so as to cause it to soften and liquify and subsequently inserting an optical fiber through the contact. The thermoset when liquified chemically reacts so as to form an epoxy adhesive which secures the optical fiber within the contact and keeps the optical fiber in place even when subjected to extremely wide temperature variations.