Abstract: An all-fiber laser oscillator comprises a laser cavity, an amplification fiber, a plurality of diode lasers, and at least one side-pump signal-and-pump combiner (combiner). The combiner comprises a double-clad fiber (DCF) and four or more multimode fibers (MMFs). DCF comprises a first taper portion, whereas each of MMFs comprises a second taper portion fused around DCF. MMFs are configured to carry a portion of combined optical energy (COE) and to couple to DCF. The first taper portion can partially compensate a beam divergence created by the second taper portion, thereby increasing a coupling efficiency of COE coupled from MMFs to DCF with improved thermal performance. In a coupling portion, a refractive index difference between MMFs and DCF is configured to form a backward coupling barrier to suppress an optical energy in DCF from coupling into MMFs, thereby protecting the plurality of diode lasers from damage.

Abstract: A compact tunable optical true time delay consists of an optical subassembly to apply dispersion-free time delay to the input optical signal, and a mechanical subassembly to facilitate tuning the delay using a linear actuator. The deployment of a precision optical ferrule sliding in a precision split sleeve offers a self-contained and inexpensive method to minimize optical misalignment during the tuning process, which releases the burden of the mechanical subassembly and is also advantageous in keeping the device compact. The exterior dimension remains unchanged at any moment despite the interior motion. Both reflection-type and transmission-type optical time delays are introduced, driven either manually or electrically.

Abstract: An optical fiber combiner comprises a double-clad fiber (DCF) and one or more multimode fibers (MMFs). DCF comprises a transition portion, a DCF taper portion, and an output section coupling to the DCF taper portion, whereas each of MMFs comprises an MMF taper configured to be fused around DCF in the transition portion. MMFs are configured to carry a combined optical energy (COE) and to couple to DCF. COE passes through the MMF taper with larger divergence of higher-order modes generated and coupled into DCF, whereas the DCF taper portion can partially offset the larger divergence. COE coupled, when traced through the output section, emerges in the air with a smaller output beam divergence of the higher-order modes, thereby preserving some of the higher-order modes in the output section and increasing a coupling efficiency of COE coupled from MMFs to DCF with improved thermal performance.

Abstract: An optical isolator device with minimized polarization mode dispersion includes a first polarization splitter/combiner, a non-reciprocal polarization rotator and a second polarization splitter/combiner. Only forward propagation of light is allowed to propagate in the device, with backward optical signal blocked due to non-reciprocal polarization rotation. The optical paths of o-ray and e-ray are arranged to achieve equal optical path lengths, which makes polarization mode dispersion minimal to nonexistent. When symmetrically configured, both polarization mode dispersion (PMD) and polarization dependent loss (PDL) become zero in principle.

Abstract: A simple, compact and low-cost passive optical transceiver device with four terminals may be used in an optical transmission system with polarization-diversity coherent detection scheme. The transceiver is composed of a first polarization splitter/combiner, a non-reciprocal polarization rotator and a second polarization splitter/combiner. The device simultaneously operates as a transmitter and a receiver with optical signals propagating along opposite directions wherein non-reciprocal polarization rotation leads to distinct effects. The received optical signal is thus split into two orthogonal polarization components directed towards two separate ports.

Abstract: An optical fiber combiner comprises a double-clad fiber (DCF) and one or more multimode fibers (MMFs). DCF comprises a transition portion, a first taper portion, and an output section coupling to the first taper portion, whereas each of MMFs comprises a second taper configured to be fused around DCF in the transition portion. MMFs are configured to carry a combined optical energy (COE) and to couple to DCF. COE passes through the second taper with larger divergence of higher-order modes generated and coupled into DCF, whereas the first taper portion can partially offset the larger divergence. COE coupled, when traced through the output section, emerges in air with a smaller output beam divergence of the higher-order modes, thereby preserving some of the higher-order modes in the output section and increasing a coupling efficiency of COE coupled from MMFs to DCF with improved thermal performance.

Abstract: A water-cooled package of a fiber-optic transport head comprising a delivery optical fiber (DOF), an interface optics, an end plug, an optically transparent tube, a tube holder comprising multiple broken cuts, and a housing operates for delivering a high-power laser light from DOF to free space. The interface optics is fusion-spiced with a section of DOF with a cladding exposed whereas the section of DOF with the cladding exposed is enclosed in a bore of the optically transparent tube, working together as a cladding mode stripper. The multiple broken cuts allow optical energy from the cladding mode stripper to randomly launch the housing in a way that the optical energy is uniformly distributed, thereby no localized hot spots possibly existed. The housing comprises a set of internal threads comprising a helix angle and a tooth height. The set of internal threads facilitates thermal dispersion, effectively reducing temperature on the housing.

Abstract: An adapter for converting the field of view (FOV) of a connector endface inspector includes a housing with a front end for connecting with a fitting tip for interfacing with a fiber-optic connector, a rear end for connecting to a front portion of the inspector, and an internal light passage. A relay lens system including a front lens group and a rear lens group is embedded inside the housing across the light passage. To achieve a converted FOV, the optical working distance of the relay lens system is made the same as the optical working distance of the connector inspector's microscope objective, and the front focal length is made larger or smaller than the rear focal length of the relay lens system. The rear lens group may be embedded in a portion of the housing that may be detached and replaced to vary the size of the converted FOV.

Abstract: A water-cooled package of a fiber-optic transport head comprising a delivery optical fiber (DOF), an interface optics, an end plug, a waterproof tube, and a housing operates for delivering a high-power laser light from DOF to free space. The interface optics is fusion-spiced with a section of DOF with a cladding exposed whereas the section of DOF is enclosed in a bore of the waterproof tube. In one embodiment, the waterproof tube comprises a first set of internal threads comprising a first helix angle and a first tooth height. In another embodiment, the housing comprises a second set of internal threads comprising a second helix angle and a second tooth height. Either one of the first set and the second set of internal threads facilitates thermal dispersion, effectively reducing temperature on the housing.

Abstract: An optical fiber coating stripper includes a pair of electrodes, each of which having a discharge head portion and an electrode portion, and a gliding plasma (GP) head housing the electrodes therein. The GP head includes internal airflow channels. The pair of electrodes are disposed at a front end of the GP head and form an air gap therebetween. Each of the discharge head portion includes a curved portion with a rib-shaped protrusion extending in a longitudinal direction of the discharge head portion. In operation, the electrodes are connected to non-alternating electrically positive and negative polarities. When a gas flows through the internal airflow channels in a direction a back end of the GP head toward the front end, a tongue-shaped GP flow is formed in the air gap between the rib-shaped protrusions of the discharge head portions.

Abstract: A fiber optic connector endface inspection probe includes a microscope system, a camera module, and an image processing system. While the objective lens of the microscope system is being moved towards and past the focused position for the endface of a mated connector, either by manually turning a focusing knob in one direction or via an automatic transmission mechanism, the camera module continuously takes and sends endface images to the image processing system, wherein a microprocessor continuously monitors the sharpness of the endface images to acquire a focused image and analyze it to make an endface inspection pass/fail judgment, without using an external display to monitor the endface images. The microprocessor further comprises an embedded web server for converting endface images and inspection report into web pages to be transmitted by a wireless transmitter of the image processing system to external devices for optional monitoring or manual inspection.

Abstract: A connector inspector includes a microscope assembly, a supporting tray, a main frame, and a fitting tip. The microscope assembly is placed within the supporting tray with a bottom cylindrical protrusion inserted into a base plate of the supporting tray, and the supporting tray is coupled with the main frame with a pair of pivoting joints. The microscope assembly is horizontally biased by a spring and an adjusting knob, set between the main frame and the microscope assembly. The microscope assembly is vertically biased by a spring and an adjusting knob, set between the main frame and the microscope assembly. Thus, the microscope assembly may be swung to shift the imaging axis in two dimensions. The design of enables the inspector to be used with just one hand. See-through windows are formed on the sides of the fitting tip for monitoring the shifting of the imaging axis.

Abstract: A water-cooled package of an optical fiber combiner (OFC) comprising an OFC assembly, a front end cap (EC), a rear EC, and a housing operates for long term reliability. The OFC assembly comprises two submounts and an OFC. Each of the two submounts comprises a U-groove in a lengthwise direction and two flat portions symmetrically connected to the U-groove in a widthwise direction. The two flat portions of each of the two submounts are mechanically coincident in a way to form a cavity between the two U-grooves of the two submounts, in which the OFC is fixed. When the OFC assembly is concentrically mated and sealed with the front EC and the rear EC, cooling water in the water-cooled package is prevented from immersing the OFC. The configurations can minimize varying stress-induced optical degradations and maintain beam quality of a laser light exiting the OFC.

Abstract: A water-cooled package of an optical fiber head comprising a delivery optical fiber (DOF), a front optical end cap (OEC), a rear OEC, a glass ferrule, and a housing operates for delivering the laser light from DOF to free space. The rear OEC is fusion-spiced with a section of DOF with a cladding exposed whereas the section of DOF is enclosed in a bore of the glass ferrule. When the glass ferrule is connected and sealed between the front OEC and the rear OEC, cooling water in the water-cooled package is prevented from immersing the section of DOF to maintain reliability of DOF. It is, therefore, not needed to bond the section of DOF in a bore of the front OEC to be waterproof, minimizing varying stress-induced speckle patterns and ultimately maintaining beam quality of the laser light exiting from DOF to free space.

Abstract: A heat-sinking package of an optical fiber combiner comprising an optical fiber combiner assembly and a case operates for a uniform temperature gradient inside the case. The optical fiber combiner assembly, fixed inside the case, comprises an overlay structure and an optical fiber combiner. The overlay structure comprises a long shallow receptacle divided by three compartments on upper side of the overlay structure, in which the optical fiber combiner is fixed with three epoxies respectively applied in the three compartments. The three epoxies with different refractive indices accommodated in the three compartments of the long shallow receptacle not only fix the optical fiber combiner in place but also serve thermal contacts to effectively disperse the heat generated in the optical fiber combiner to the overlay structure, further dispersing to surroundings of the case. The overlay structure further comprises one or more thermally conductive sheaths to more efficiently disperse the heat.

Abstract: A connector inspector includes a microscope assembly, a supporting tray, and a main frame. The microscope assembly is placed within the supporting tray with a bottom cylindrical protrusion inserted into a base plate of the supporting tray, and the supporting tray is coupled with the main frame with a pair of pivoting joints. The microscope assembly is horizontally biased by a spring and an adjusting knob, both set between the main frame and the microscope assembly. The microscope assembly is vertically biased by a spring and an adjusting knob, both set between the main frame and the microscope assembly. Thus, the microscope assembly is able to swing to shift the imaging axis of the microscope assembly in two dimensions using the two adjusting knobs respectively. Because the biasing means for the imaging axis are built inside the inspector, the inspector may be used with just one hand.

Abstract: A heat-reduced package of an optical fiber head comprising a delivery optical fiber (DOF), a cladding mode stripper, an optical end cap, a beam shaper, a window, and a housing operates for delivering the laser light from DOF to free space with a uniform temperature gradient inside the housing while maintaining beam quality. The cladding mode stripper comprising a section of cladding-exposed DOF inside bore of the glass ferrule fused together is effective to remove cladding modes from DOF. The optical end cap comprising a corrugated structure is configured to deflect the cladding modes, reduce optical feedback, and facilitate optical and thermal dispersion. The housing comprises another corrugated structure on an inner wall to absorb undesired optical energy. The housing may further comprise a cooling slot to disperse the heat accumulated in the housing to its surroundings.

Abstract: A compact configuration of a multiport fiber array and a multi-surface optical lens constitutes a low modal noise multimode fiber optical power splitter. In a digital optical system, modal noise manifests itself in modal dependent intensity noise and modal dependent timing jitter. A compact two-part end coupling design improves both properties and is more cost effective, making it a suitable solution for future high bit rate optical system applications.

Abstract: A light-emitting diode (LED)-based solid-state lamp using an LED driving circuit with an electric current control operates normally for a regulated power from either a compact fluorescent (CFL) electronic ballast or AC mains. The LED driving circuit together with a matching circuit is configured to optimize resonant characteristics of the CFL electronic ballast used and enhance lamp compatibility without flickering, which in turn reduces possibility of overheating and fires due to incompatibility. With a cycle-by-cycle current control and power switching at a constant on-time and varied off-time, an over-rated surge current is limited, preventing occasional fire hazards occurred in both the CFL electronic ballast and the LED lamp.