Abstract: An optical delay circuit includes a plurality of defect waveguides arranged in parallel and including a line-shaped defect in a periodic refractive-index distribution structure of a photonic crystal. The defect waveguides include a multiplexing/demultiplexing portion in which the defect waveguides are arranged close to each other to multiplex and demultiplex light; and an optical delay portion extending from the multiplexing/demultiplexing portion, in which the defect waveguides are arranged with a predetermined distance therebetween so that light propagating in any of the defect waveguides does not interfere with light propagating in the other defect waveguides. Each of the waveguides has a different configuration.

Abstract: A novel optical time division multiplexing (OTDM) module based on hybrid-integrated optical chips is disclosed. An integrated modulator chip generates optical RZ signal streams which are then interleaved in an integrated time-delay chip to produce an OTDM signal. The integrated modulator chip is coupled and secured to the integrated time-delay chip via a suitable optical index-matching layer or collimating lenses. Such an approach alleviates the stability problems offered by conventional fiber-based OTDM technology and aids in reducing the size and complexity as well as lowering the cost for the assembly. Furthermore, the time-delay chip of the present invention offers fine tuning capabilities thereby allowing for slight adjustments in the interleaving of optical signal streams when non-standard data transmission rates are required.

Abstract: A method and system for self-synchronizing an optical packet network by selecting a seed pulse from among the data pulses within a packet having no synchronization marker, transforming the seed pulse to be optically distinguishable from the remaining data pulses after the packet has been transmitted, and extracting that seed pulse for use in synchronizing the operation of the network. In one embodiment, the process is practiced using a intensity modifier (such as a fast-saturation, slow-recovery amplifier) to modify the seed pulse intensity, and an intensity discriminator (such as an unbalanced NOLM, or a dispersion-shifted fiber and bandpass filter) to extract the differentiated seed pulse.

Abstract: A method of splitting an optical data signal starting with an optical data signal split into n equal data sub-signals, and an optical binary auxiliary signal with the same bit rate and phase is added to each optical data sub-signal. Each nth bit of the optical binary auxiliary has a higher level, with the phases of each of the n optical auxiliary signals showing a relative displacement of one bit. As a result, n aggregate signals are generated, each of which is fed to a decision-maker. A decision-maker threshold is set above the amplitude of the data sub-signal and below the amplitude of the aggregate signal. Each decision-maker, therefore, emits an electrical data signal with 1/n times the bit rate of the data signal.

Abstract: A photonic crystal comprising a waveguide made of material. The waveguide has a periodic set of holes. The material proximate to at least one of the holes in the periodic set of holes exhibits an index of refraction that has been modified by the application of laser energy relative to the material proximate to other holes in the periodic set of holes.

Abstract: One embodiment disclosed relates to a method for calibrating an array of light-modulating elements. The method includes illuminating the array of elements, modulating an intensity of light diffracted by the elements over a modulation range, and measuring the modulated light intensity from each element of the array using a linear detector. Other embodiments disclosed relate to an apparatus and system for calibrating an array of light-modulating elements. The apparatus includes a light source for illuminating the array of elements and a linear detector for measuring light intensities at points along a line segment. The apparatus is configured so that modulated light from each of the elements impinges upon a different point of the line segment. The system includes means for modulating an intensity of light diffracted by the elements over a modulation range and a detector for measuring the modulated light intensity from each element of the array.

Abstract: A demultiplexer for an optical time-division multiplexed digital signal, which has a signal wavelength ?s and is transmitted with a bit rate B, is described. It comprises a Raman active optical medium, a pump source for generating a periodic optical pump signal having a pump wavelength ?p and a periodicity of B/n where n is an integer ?2, and a coupler for coupling the digital signal and the pump signal into the Raman active optical medium. The new demultiplexer exploits the non-linear Raman gain response of the Raman active medium to a high power pump signal and has a narrow time window and a high extinction ratio.

Abstract: A fully “time tunable” all-optical switch routes/switches digital bits (packets) in an all-optical format for transmission, or for further processing, in an all-optical communication network. The all-optical switch is implemented in either a semiconductor hybrid or in a completely monolithic form. Variable time delay elements adjust the time delay of a clocking signal input and a data packet input. The clocking signal determines the state of two nonlinear optical elements, such as semiconductor optical amplifiers, incorporated in the upper and lower arms of a Mach-Zehnder configuration. An optical coupler is connected to the output of the all-optical switch. The output of data from selected ports of the optical coupler is controlled using the variable time delay elements.

Abstract: An optical network has an optical splitter connected to (1) a working optical subscriber unit (OSU) of a working circuit via a working optical fiber, (2) a protection OSU of a protection circuit via a protection optical fiber, and (3) one or more optical network terminals (ONTs), where the protection OSU has a protection burst mode receiver (BMR) configured to receive an upstream optical signal from the optical splitter. The algorithm determines whether the protection OSU is functioning improperly. A reset pulse is applied at the protection BMR at a particular timing position and an attempt is made to interpret the current upstream cell received at the protection BMR. This process is repeated using different timing positions for the BMR reset pulse until the current upstream cell is correctly interpreted, e.g., based on the correct identification of an ATM header error correction (HEC) byte in the upstream cell.

Abstract: An optical network has an optical splitter connected to (1) a working optical subscriber unit (OSU) of a working circuit, (2) a protection OSU of a protection circuit, and (3) one or more optical network terminals (ONTs), where an ONT has (i) a working line termination (LT) unit of the working circuit and connected to the optical splitter via a working optical fiber and (ii) a protection LT unit of the protection circuit and connected to the optical splitter via a protection optical fiber. The present invention enables fast protection switching from the working circuit to the protection circuit. The arrival times of corresponding downstream cells are measured at both the working and protection LT units of the ONT, and information related to the arrival times is transmitted from the ONT to the protection OSU.

Abstract: In a light transmission equipment which can generate a desired concatenation signal from a maximum concatenation signal standardized in a synchronous transmission mode, a master and a slave circuit for clock change are provided respectively inputting at least two data at a maximum transmission rate based on a concatenation standard of a synchronous transmission mode obtained by dividing a desired transmission rate not prescribed in the concatenation standard to perform a concatenation control to the slave circuit by control information from the master circuit side.

Abstract: A high-speed access data network in which upstream and downstream traffic is logically or physically separated. The network can use the Ethernet media access control (MAC) layer protocol over distances that are much larger than conventionally possible with the Ethernet MAC layer protocol. In a configuration including a central office and multiple subscribers, the central office is removed from the collision domain, which can be made relatively small, without limiting the distance between the central office and the subscribers. The downstream data rate is not limited by the size of the collision domain and can thus be made almost arbitrarily large. Furthermore, by allowing a smaller collision domain, greater upstream data rates can be used. It is thus possible to use ubiquitous and inexpensive Ethernet LAN technology in highly cost-sensitive applications such as residential broadband access.

Abstract: An automated optical transport system is provided which provides for automatic discovery of system components, automatic inventory of system components, automatic topology detection, automatic provisioning of channels, and automatic characterization and tuning of system components and fiber. The invention provides automation capability through inclusion of management card capabilities at each station which communicates through a reverse propagating service channel. Dynamic and propagation direction independent segments are provided in conjunction with a token-based scheme to repeatedly tune, update and monitor the transport system.

Abstract: An optical time multiplexer for generating an N Gbits/s output signal (36) from n data modulated input pulse streams (21, 22) with a pulse frequency of N/n GHz, where n∈IN and n≧2, with a combiner device for passively interleaving the n input pulse streams (21, 22) is characterized by at least n−1 first phase shifting elements (25) tuning the optical phases of at least n−1 input pulse streams (22) and being connected to a controller device (32), which derives at least n−1 control signals from a comparison of the optical phases of the n input pulse streams (21, 22) and controls the at least n−1 first phase shifting elements (25) such that the optical phases of all n input pulse streams (21, 22) are locked with respect to each other.

Abstract: A fully “time tunable” all-optical demultiplexer selects which digital bits or groups of bits in an all-optical data packet or all-optical data burst are to be read/demultiplexed. The all-optical demultiplexer is implemented in either a semiconductor hybrid or in a completely monolithic form. The all-optical demultiplexer is formatted in either a “normally on” or “normally off” configuration. Variable time delay elements adjust the time delay of a clocking signal input and a data packet input. The clocking signal determines the state of two nonlinear optical elements, such as semiconductor optical amplifiers, incorporated in the upper and lower arms of a Mach-Zehnder configuration. Only desirable digital bits or groups of bits are outputted from the demultiplexer. All other undesirable bits are suppressed.

Abstract: An optical packet header identifier having a simplified configuration and being superior in reliability, stability, and economical efficiency, an optical router incorporating the identifier therein, and a routing method using the optical router are provided.