Abstract: The thermo-optic behavior of an optical path over a range of temperatures is controlled by determining a figure of merit (FoM) for the optical path and including in the path a body of NaBi(Mo1-xWxO4)2 crystalline material that enables the conditions specified by the FOM to be satisfied. The NaBi(Mo1-xWxO4)2 crystalline material is highly transparent at a wavelength of radiation propagating in the path, and has a coefficient of thermal expansion (CTE) and a refractive index n such that the CTE and dn/dT of the etalon compensate one another so as to perform frequency discrimination that is essentially temperature insensitive over the range ?T. The NaBi(Mo1-xWxO4)2 crystalline material exhibits temperature independent transmission characteristics at about room temperature and at a wavelength of about 1550 nm.

Abstract: A barrier net across a space defined by the fuselage of an aircraft and a floor of the aircraft comprises a plurality of intersecting net members, at least some of the members being attached to the fuselage by attachment structures attached to attachment points on the fuselage of the aircraft and held forward of the attachment points so that a major portion of the net is in a plane further forward than the attachment points.

Abstract: A thimble providing a first convex surface about a first axis and a second convex surface about a second axis, the first and second axes being substantially perpendicular to each other and the first and second surfaces being opposite each other, the thimble being such that a first length of elongate material can be wrapped over said first convex surface and back on itself to form a first loop around the thimble and a second length of elongate material can then be wrapped over said second convex surface through said first loop and back on itself to form a second loop around the thimble.

Abstract: A barrier net (12) across a space defined by the fuselage (6) of an aircraft and a floor (7) of the aircraft comprising a first plurality of parallel lengths (13) orientated in a first direction transverse to a second plurality of parallel lengths (14) orientated in a second direction wherein the lengths (13, 14) have fastening means at each end which provide a means for fastening the net to attachment points on the aircraft fuselage (6), characterised in that neither the first nor the second plurality of lengths (13, 14) is parallel to said floor (7).

Abstract: A method of increasing the monomolecular recombination and the immunity to noise of a continuously tunable laser is disclosed. A concentration of recombination centers in the range of about 1×1016 cm?3 to about 1×1018 cm?3 in the tuning region of the laser device is achieved by doping the waveguide layer with impurity atoms, by irradiating the waveguide layer with high energy particles or by varying the growth conditions of the waveguide layer to introduce native point defects due to lattice mismatch. This way, the monomolecular recombination is increased and the radiative recombination over low current ranges is reduced. By increasing the monomolecular recombination, the immunity to noise is improved but the tuning efficiency is reduced. Nevertheless, only a minimal effect on the tuning efficiency is noted over high current ranges and, therefore, the overall tuning range is only insignificantly changed.

Abstract: A net comprising a combination of a plurality of lengths (2, 3) of a first material with a plurality of lengths (11) of a second material having a relatively lower elongation than that of the first material in which at least some of the lengths (2, 3) of first material are transverse to at least some of the lengths (11) of second material.

Abstract: A cargo barrier (9) in or for installation in an aircraft (2), the barrier (9) comprising a peripheral frame structure (10) of rigid material and a cargo restraining net (11), the frame structure (10) being, in the aircraft (2), attached to attachment points on the interior structure of the aircraft and the net being attached to attachment points (12) on the frame structure (10). The frame structure (10) and net (11), in use, form a barrier across an interior space of the aircraft (2) in order to restrain longitudinal movement of cargo within the aircraft (2).

Abstract: The present invention provides a method and apparatus for compensating for the age induced wavelength drift in a tunable DBR. In practice, the tuning characteristic (i.e. output wavelength versus tuning current) of a tunable DBR may be characterized before and after factory aging, typically in the form of a burn-in or purge cycle. An aging vector may be constructed in accordance with the ratio of the change in the tuning characteristic associated with a second output wavelength and the change in the tuning characteristic associated with a first output wavelength as a function of the factory aging. In addition, the tuning characteristic associated with transmission at the first output wavelength may be monitored in the field.

Abstract: The present invention provides a method and apparatus for compensating for the age induced wavelength drift in a tunable DBR. In practice, the tuning characteristic (i.e. output wavelength versus tuning current) of a tunable DBR may be characterized before and after factory aging, typically in the form of a burn-in or purge cycle. An aging vector may be constructed in accordance with the ratio of the change in the tuning characteristic associated with a second output wavelength and the change in the tuning characteristic associated with a first output wavelength as a function of the factory aging. In addition, the tuning characteristic associated with transmission at the first output wavelength may be monitored in the field.

Abstract: A multi-service subscriber radio unit includes an antenna and a transceiver which is operatively coupled to the antenna. The radio unit further includes a modem which is coupled to the transceiver and a packet control unit. The packet control unit provides multi-service packetized data for transmission (up-link) to the modem and receives multi-service packetized data from the modem (down-link). The packet control unit extracts service specific packetized data from the received multi-service packetized data and also generates the transmit multi-service packetized data from a plurality of service specific data from customer premise equipment. A plurality of service interface units are included which provide a suitable electrical interface between the customer premise equipment and the radio unit. A distribution control unit is interposed between the packet control unit and the plurality of service interface units.

Abstract: A method of increasing the monomolecular recombination and the immunity to noise of a continuously tunable laser is disclosed. A concentration of recombination centers in the range of about 1×1016 cm−3 to about 1×1018 cm−3 in the tuning region of the laser device is achieved by doping the waveguide layer with impurity atoms, by irradiating the waveguide layer with high energy particles or by varying the growth conditions of the waveguide layer to introduce native point defects due to lattice mismatch. This way, the monomolecular recombination is increased and the radiative recombination over low current ranges is reduced. By increasing the monomolecular recombination, the immunity to noise is improved but the tuning efficiency is reduced. Nevertheless, only a minimal effect on the tuning efficiency is noted over high current ranges and, therefore, the overall tuning range is only insignificantly changed.

Abstract: The thermo-optic behavior of an optical path over a range of temperatures is controlled by determining a figure of merit (FoM) for the optical path and including in the path a body of NaBi(Mo1−xWxO4)2 crystalline material that enables the conditions specified by the FOM to be satisfied. The NaBi(Mo1−xWxO4)2 crystalline material is highly transparent at a wavelength of radiation propagating in the path, and has a coefficient of thermal expansion (CTE) and a refractive index n such that the CTE and dn/dT of the etalon compensate one another so as to perform frequency discrimination that is essentially temperature insensitive over the range &Dgr;T. The NaBi(Mo1−xWxO4)2 crystalline material exhibits temperature independent transmission characteristics at about room temperature and at a wavelength of about 1550 nm.

Abstract: A monolithically integrated light source and frequency discriminator has a section in which a single frequency optical signal is produced and a section in which the frequency is sensed. The output of the optical discriminator is connected to a controller for stabilizing the output frequency of the light source.

Abstract: A fiber Raman amplifier is configured to use a co-propagating Raman pump source, which may be beneficial in a variety of system configurations (for example, in bidirectional communication systems). By carefully configuring the pump source characteristics, sufficient optical gain can be achieved in the co-propagating arrangement, the characteristics including: (1) using an optical pump power of at least 50 mW, (2) having a relatively large spectral bandwidth within the pump (to suppress SBS); and (3) a frequency difference between all longitudinal pump modes of each pump laser being separated by at least the walk-off frequency between the pump laser frequency and the signal frequency, and all intense longitudinal modes between different pump lasers being separated by at least the electrical bandwidth of the communication system.

Abstract: A fiber Raman amplifier is configured to use a co-propagating Raman pump source, which may be beneficial in a variety of system configurations (for example, in bidirectional communication systems). By carefully configuring the pump source characteristics, sufficient optical gain can be achieved in the co-propagating arrangement, the characteristics including: (1) using an optical pump power of at least 50 mW, (2) having a relatively large spectral bandwidth within the pump (to suppress SBS); and (3) a frequency difference between all longitudinal pump modes of each pump laser being separated by at least the walk-off frequency between the pump laser frequency and the signal frequency, and all intense longitudinal modes between different pump lasers being separated by at least the electrical bandwidth of the communication system.

Abstract: A method is disclosed for frequency stabilization of an optical source, using data obtained from a frequency stabilization system based on an optical frequency discriminator to stabilize the output of a laser to a particular grid channel. The data is mathematically manipulated to double the number of channels as compared to prior art methods and allows arbitrary channel spacing about the channels.

Abstract: A method and device for obtaining a desired phase of optical characteristic of a Fabry-Perot (FP) etalon using multiple optical detectors which, while passively aligned at various positions relative to an incident light beam, detect different phases of light signal emerging from the FP etalon. An FP etalon and optical detector array constructed in accordance with the present invention may be used as a frequency discriminator in an optical system where the FP etalon optical characteristic is required to have a particular phase.

Abstract: A cargo net includes a plurality of interconnected strands defining a border wherein a plurality of tensioning fittings are mounted and wherein each fitting is formed with a closed ring-like portion having at least one integral prong projecting inwardly of the ring. Constrictions on the prong and ring cooperate to retain a selected strand of the net in position over the prong. A closed eyelet opposite the prong receives another strand of the net.

Abstract: In an overhead luggage bin for the passenger cabin of an aircraft, the bin has an opening with at least two hinged doors being provided at the bin opening. The bin includes at least one telescopically extensible spring strut device. In such a device a spring is resiliently loaded as the strut telescopically contracts. The spring strut device operates on two of the doors simultaneously through the medium of a differential mechanism. The thrust of the spring strut device tends to open the two doors simultaneously and the differential mechanism permits the two doors to be opened and closed, one relative to the other.

Abstract: A DFB laser with improved loss grating is disclosed. The grating contains periodically patterned first and second semiconductor layers that are embedded in semiconductor material of composition selected to provide relatively low loss for the laser radiation. The composition of the first layer is selected to provide a relatively high refractive index and loss for the laser radiation, and the composition of the second layer is selected to provide relatively low refractive index and loss for the laser radiation. The thicknesses of the first and second layers are selected such that the real part of the coupling constant .vertline..kappa.'.vertline. is less than the imaginary part of the coupling constant .vertline..kappa.".vertline.. In preferred embodiments .vertline..kappa.'.vertline..ltoreq.0.5.vertline..kappa.".vertline., even.ltoreq.0.2.vertline..kappa.".vertline..