Abstract: A plurality of active gain material (93) is disposed in an active interface portion (44) of a dielectric band-gap cladding confinement region (22) adjacent to a dielectric core (12) of a photonic band-gap crystal fiber (20), wherein during operation, the plurality of active gain material (93) absorbs the pump energy and stores the pump energy as a potential energy storage for stimulation by EM energy in a second guided mode at a second frequency in a second range of frequencies for overlapping with the first guided mode of the core (12) such that the surface defined by an interface between the photonic band-gap cladding (22) and the dielectric core (12) that supports at least one surface mode propagating at that interface (44) overlaps the active interface portion of the dielectric cladding confinement region and a state associated with the dielectric core (12).

Abstract: An array tester (10) characterizes individual ones (111) of a semiconductor devices of an array (11) based on polarization-resolving an optical far-field measurement of the individual chips (111) as a function of angular position. Two pairs of TM and TE detectors (41a-b and 42a-b) or one pair displaceable by ninety degrees, move in vertical and horizontal arc paths or fixed around a fixed position of a selected device of an array to sample the far-fields.

Abstract: A multi-channel modular device (10) processes between two fluid streams of different compositions. The device (10) includes a porous body (150) having a first plurality of feed-flow pathways (110) disposed in the body (150) for transporting a first stream (180). A pathway wall (114) surrounds each of the first plurality of feed-flow pathways (110) for processing the first stream (180) into a first composition (1852) and a second composition (1802). At least one feed-flow inlet (1101) is disposed in the body (150) for introducing the first stream (180) into the first plurality of feed-flow pathways (110). At least one feed-flow outlet (1102) is disposed in the body (150) for discharging the remaining first stream containing the second composition (1802). At least one second pathway (210) is disposed in the body (150) for transporting a second stream (280) having a second inlet (2101) and a second outlet (2102).

Abstract: For suppressing intra-channel four wave mixing in a time division multiplexing (TDM) system, where N synchronous data streams, each having a reduced data pulse width within a bit slot timing interval, from parallel to serial form, are converted for optically bit interleaving the N synchronous data streams into the optical communication link at a nominal bit slot delay between sequential N synchronous data streams related to the bit slot timing interval to provide a serial data sequence of short optical pulses having an equal bit slot delay between sequential pulses, a sequential bit slot delay is varied between two of the short optical pulses to provide an unequal bit slot delay between sequential pulses within the serial data sequence of short optical pulses for suppression of undesired intra-channel four-wave mixing pulses among the pulses and thereby, improvement of transmission performance.

Abstract: An optically-active air-clad fiber (30) includes a core (34, 84) that facilitates doping with an ion optically excitable and having a three-level optical transition when pumped at a first end (28) of an optical cavity (46) by a multimode pump source (72) at a pump wavelength (64) for lasing at a signal wavelength (66) different than the pump wavelength (64) at a second end (29) of the optical cavity (46), the core (34, 84) having a refractive index, wherein the core (34, 84) is transformed from the first end to proximate the second end (29) thereof such that the optically-active fiber (30) is multimode at the pump wavelength proximate to the first end (28), and is single-mode at the signal wavelength proximate to the second end (29). An air-clad (36, 86) surrounds at least one portion of the core (34, 84) and has a lower effective refractive index than the refractive index of the core (34, 84).

Abstract: A tunnel junction device (102) with minimal hydrogen passivation of acceptors includes a p-type tunnel junction layer (106) of a first semiconductor material doped with carbon. The first semiconductor material includes aluminum, gallium, arsenic and antimony. An n-type tunnel junction layer (104) of a second semiconductor material includes indium, gallium, arsenic and one of aluminum and phosphorous. The junction between the p-type and an-type tunnel junction layers forms a tunnel junction (110).

Abstract: An optical device (10) includes a broad area laser (72) for lasing at a first wavelength (64), a multimode active-doped tapered waveguide laser (6); and a multimode passive planar mode transformer (118) coupling and tapering from the broad area laser (72) to the multimode active-doped tapered waveguide laser (6).

Abstract: A tunnel junction device (102) with minimal hydrogen passivation of acceptors includes a p-type tunnel junction layer (106) of a first semiconductor material doped with carbon. The first semiconductor material includes aluminum, gallium, arsenic and antimony. An n-type tunnel junction layer (104) of a second semiconductor material includes indium, gallium, arsenic and one of aluminum and phosphorous. The junction between the p-type and an-type tunnel junction layers forms a tunnel junction (110).

Abstract: An integrated semiconductor device comprising a laser on a substrate, the laser having an active layer and a current-induced grating, such as a current-injection complex-coupled grating, within a laser cavity producing a single-mode output light signal at high data rates (>622 Mb/sec) in isolator-free operation. The grating has a coupling strength product ?L greater than 3, where ? is the coupling coefficient and L is the length of the laser cavity. In certain embodiments, the laser is a distributed feedback (DFB) laser that emits light at a wavelength of about 1.5 ?m. The strong current-induced grating prevents mode hopping between multiple degenerate Bragg modes. The laser is also characterized by excellent immunity from optical feedback, and can be operated without an isolator at high data rates.

Abstract: The invention relates with an optical bench for optoelectronic packages comprising a rigid insulating substrate, the substrate having a top surface along which it is defined an optical axis, the substrate comprising: a device region for mounting at least an optoelectronic device in alignment with the optical axis, and a fixing region adjacent to the device region for affixing at least an optical component in alignment with the optical axis. The substrate further comprises a third region provided with metallised tracks, the third region extending over the substrate top surface along at least part of one side of the fixing region in a direction substantially parallel to the optical axis. The invention also relates with an optical bench comprising: a single baseplate having a device region and a fixing region; a welding platform mounted directly on said fixing region; a heat sink mounted directly on said device region; and an optoelectronic device directly mounted on said heat sink.

Abstract: A method of making an all-fiber Mach-Zehnder interferometer comprising at least two optical fibers comprises the steps of bringing the fibers in a reciprocal contact relationship for a contact section thereof; fusing together and tapering the fibers in at least a first portion of said contact section; forming at least two optical couplers between the fibers in a second and a third portions of said contact section, located at opposite sides of said first portion.

Abstract: A conversion method for converting a unipolar voltage data stream into a carrier-suppressed return-to-zero (CSRZ) optical data stream includes modulating a continuous optical wave with an encoded nonreturn-to-zero (NRZ) voltage data stream for providing a CSRZ optical data stream of full-width at half-maximum (FWHM) pulse width less than one-half of the transition time of the encoded nonreturn-to-zero (NRZ) voltage data stream between logical states for a reduced pulse width. The modulating circuit is either a duobinary modulator driven with a swing of ±2V? or an optical time domain multiplexed plurality of nonreturn-to-zero (NRZ) modulators with phase shifting and differential encoding.

Abstract: An optically active fiber (30) is disclosed for making a fiber laser (18) or an amplifier (16). This double-clad structured active fiber (30) has a core (34), doped with an optically excitable ion having a three-level transition. The core (34) has a core refractive index and a core cross-sectional area. An inner cladding (32) surrounds the core (34). The inner cladding (32) has an inner cladding refractive index less than the core refractive index, an inner cladding cross-sectional area between 2 and 25 times greater than that of the core cross-sectional area, and an aspect ratio greater than 1.5:1. An outer cladding (36) surrounds the inner cladding (32) and has an outer cladding refractive index less than the inner cladding refractive index.

Abstract: A modulator formed with a solid state electro-optic material having a pixellated structure interconnected to a circuit on a semiconductor substrate. Silicon CMOS integrated circuit that can include random access memories (RAMs) are used as a substrate and interfaced to solid state electro-optic materials coated thereon. In particular, the electro-optic modulators are controlled by RAM cells to produce a modulation of reflected light. SRAMs can be used with connection to the SRAM cell flip-flop. DRAMs can be used with the modulator replacing the DRAM storage capacitor. The SLM thus formed can be connected to a digital computer and controlled as if were a being written to as a memory, but other IC structures can also be used. In order to enhance the modulation effects, the electro-optic material is used as the spacer for a Fabry-Perot etalon structure that is also deposited on the semiconductor substrate. PLZT is a suitable electro-optic material.

Abstract: An avalanche photodiode (APD) includes an absorption layer above the multiplication layer, where the thickness of the multiplication layer is defined through a growth process. The APD can also have a third-terminal, or peripheral ring terminal, for collecting charge carriers generated outside the optically-active region of the device. Undesirable dark current can thus be better managed during the life of the device. The three-terminal design may also be utilized in other photodetectors, including PIN diodes.

Abstract: A multiple spectral line Raman laser having adjustable relative power output between different spectral lines is provided. The laser includes a lasing cavity, first and second reflectors optically coupled to a back end of the cavity that reflects substantially all light having wavelengths of &lgr;1 and &lgr;2, respectively, and a tunable reflector assembly optically coupled to a front end of the cavity that reflects a selected proportion of said light having wavelengths of &lgr;1 and &lgr;2 in response to a single source of strain to control relative power output of light at these wavelengths. The lasing cavity may be a linear length of gain fiber, and the tunable reflector may include a single fiber Bragg grating (FBG) having a trapezoidal reflection profile, or a pair of fiber Bragg gratings mounted on either side of a flexible substrate such that when the substrate is bent, one FBG stretches while the other is compressed.

Abstract: A mode transformer (10) includes a passive waveguide (120) having a first composition co-existing with a second composition to provide a guided optical wave (250). A p-doped re-growth layer (130) having the first composition is disposed on top of the passive waveguide (120). A compensated n-doped buffer (110) is disposed underneath the passive waveguide (120). The compensated n-doped buffer (110) has the first composition and a sufficient concentration of a third composition such that the compensated n-doped buffer layer has a reduced index difference between the p-doped re-growth layer (130) and the compensated n-doped buffer layer (110) to compensate the index difference between the p-doped re-growth layer (130) and the originally un-compensated n-doped buffer in order to preserve the symmetry of the guided optical wave (250).

Abstract: An optically active waveguide laser (30) includes a multimode portion (126) for carrying more than one spatial mode at a predetermined wavelength chosen from a bandwidth including a pump wavelength (64) and the lasing wavelength (66). The multimode portion (126) has a first refractive index. A cladding portion (386) is proximate the multimode portion (126). A multimode grating (60, 56, or 62) is written on at least one section (26) of the multimode portion for reflecting the predetermined wavelength.

Abstract: A broadband interconnection device (10) used for interconnection between a first transmission line (100) and a second transmission line (200), has a substrate (300) with the first transmission line (100) defined at a first side (310) on a first surface (320), the first transmission line (100) including a signal conductor (120) and at least one ground conductor (121 or 122), a signal conductor (220) of the second transmission line (200) defined on an opposite side (340) of the first surface (310), and a ground plane (260) of the second transmission line (200) on an opposed surface (360), the signal conductor (120) of the first transmission line (100) being electrically connected to the signal conductor (220) of the second transmission line (200) on the first surface (320). On the opposed surface (360), the ground plane (260) of the second transmission line (200), has at least one protrusion (261) aligned with the signal conductor (120) of the first transmission line (100).

Abstract: A device (16) in a system (10) modulates an optical signal (13) and tunes the duty cycle of the optical signal (13) for optimizing system performance as a response of the duty cycle. The device (16) includes a tunable duty-cycle Mach-Zehnder interferometer (MZI) acting as a pulse-width shaper (160) for modulating the optical signal (13) and tuning the duty cycle of the optical signal (13). The MZI (160) has a transmittance transfer function of the interferometer (160). At least one electrode structure (163) generates a DC voltage and an AC voltage for biasing and controlling the swing of the Mach-Zehnder interferometer (160) with the respective amplitudes of the DC and AC voltages such that the maximum power transmittance point on the transfer function is less than 100% for tuning the duty cycle of the optical signal (13) such that system performance is optimized.