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 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 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: An LED lighting device with a replaceable driver-control module interface is described. The LED lighting device may include a driver-less LED lighting device, a driver-control module with driver function, and a housing interface on the driver-less LED lighting device to house and connect the driver-control module. The driver-less LED lighting device receives AC from an external AC source and passes the AC to the driver-control module. The driver-control module receives AC from the driver-less LED lighting device and provides DC to the driver-less lighting device to drive LED diodes in the driver-less LED lighting device. The housing interface on the lighting device houses the driver-control module such that, when the driver-control module is fastened to the driver-less lighting device through the housing interface, the driver-control becomes an integral part of the lighting device.

Abstract: A linear light-emitting diode (LED)-based solid-state universal lamp using an all-in-one LED driving circuit with a power factor correction (PFC) and control device operates normally for a regulated power and current from either electronic ballast or AC mains. The all-in-one LED driving circuit is configured to operate in a wide range of input voltages and frequencies, especially for various high voltages and high frequencies associated with various electronic ballasts. 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 the ballast. When two shock protection switches are used in two lamp bases in the lamp, the universal lamp fully protects a person from possible electric shock during initial installation and re-lamping.

Abstract: A linear light-emitting diode (LED)-based solid-state universal lamp using a frequency sensing and control mechanism operates normally with both an electronic ballast and the AC mains. The frequency sensing and control mechanism automatically detects voltage types associated with output voltages from the ballast and the AC mains in a single-ended or a double-ended lamp fixture and makes proper management so that the universal lamp works for either case and in either fixture without operational uncertainty. When two shock protection switches are used in two lamp bases, the universal lamp fully protects a person from possible electric shock during initial installation and re-lamping.

Abstract: A linear light-emitting diode (LED)-based solid-state lamp using an AC current control scheme and shock protection switches operates normally with an electronic ballast. Due to the use of shock protection switches in the two lamp bases at two opposite ends, the ballast-compatible LED lamp fully protects a person from possible electric shock during initial installation, maintenance, and re-lamping no matter what the rated power and the brand of the LLT lamp are and no matter whether the electronic ballast is existing used ones that may be incompatible with the lamp or faulty, leading to an unacceptable leakage current.

Abstract: Embodiments of an optical assembly for use in polarization rotation applications are disclosed. In one aspect, an optical assembly includes a polarization beam splitter a rotational element and a path exchange mirror. The temperature, wavelength and manufacturing dependencies of polarization rotation of this optical assembly are minimal to nonexistent compared to conventional Faraday rotation assemblies as the optical fiber accepts only the desired rotation. As such these optical assemblies have no temperature and wavelength dependencies of the polarization rotation angle over broad temperature and wavelength ranges with minimal additional losses. In another aspect, the polarization dependence of reflection from the path exchange mirror is managed so as to minimize the polarization effect associated with oblique incidence.

Abstract: Embodiments of an end-cap for an LED tube are described. In one aspect, an end-cap for an LED tube may include an end-cap housing, at least one elastic component, and a connecting assembly. The end-cap housing may include at least one power pin thereon and configured to connect to an external power source. The elastic component may reside inside the end-cap housing. The end-cap housing may connect to a first end of the connecting assembly via an extendable connection and a second end of the connecting assembly opposite to the first end thereof connects to a body of the LED tube through at least one power connector. The power connector may connect to the at least one power pin when the elastic component is pressed. The power connector may remain separate from the at least one power pin when the elastic component is not pressed.

Abstract: Embodiments of an end-cap with retractable and rotatable pin for an LED tube are described. In one aspect, an end-cap for an LED tube may include an end-cap housing, an end-cap base assembly, a power-pin assembly, and at least one elastic component. The power-pin assembly may include at least one power pin thereon and configured to connect to an external power source. The power-pin assembly may protrude out of a center opening of the end-cap housing. The end-cap base assembly may have at least one power connector one end of which is connected to the body of the LED tube to receive electric power. The at least one elastic components may reside inside the end-cap housing and is placed between the power-pin assembly and the end-cap base assembly. The power connector may connect to the at least one power pin when the at least one elastic component is pressed.

Abstract: A linear light-emitting diode (LED)-based solid-state universal lamp using a degenerate voltage sensing and control mechanism operates normally in both single-ended and double-ended linear tube lamp fixtures. The degenerate voltage sensing and control mechanism automatically detects power source configuration in the fixture and makes proper management so that the universal lamp works in any fixtures without operational uncertainty or risk of fire. When used with shock protection switches in the two lamp bases at two opposite ends, the universal lamp fully protects a person from possible electric shock during initial installation and re-lamping.

Abstract: A dimming and CCT tuning system comprises a controller and multiple LED-based lighting devices. Each lighting device comprises a control circuit, at least two LED driving circuits, and at least two types of LED-based light sources. When the controller receives the dimming and CCT tuning signals from its inputs, it generates a modulated dimming and CCT tuning signal portion in the AC voltage delivered to the multiple lighting devices. Afterwards, a regular AC power is delivered. In receiving, each lighting device demodulates such signal portion and generates at least two control signals to the at least two LED driving circuits which then individually power the at least two types of LED-based light sources to emit desired light levels and CCTs. The system eliminates extra wires required in 0-10 V dimming control and maintains an undistorted AC waveform in most of operating time, not like a TRIAC dimming.

Abstract: A dimming and CCT tuning system comprises a controller and multiple LED-based lighting devices. Each lighting device comprises a control circuit, at least two LED driving circuits, and at least two types of LED-based light sources. When the controller receives the dimming and CCT tuning signals from its inputs, it generates a modulated dimming and CCT tuning signal portion in the AC voltage delivered to the multiple lighting devices. Afterwards, a regular AC power is delivered. In receiving, each lighting device demodulates such signal portion and generates at least two control signals to the at least two LED driving circuits which then individually power the at least two types of LED-based light sources to emit desired light levels and CCTs. The system eliminates extra wires required in 0-10 V dimming control and maintains an undistorted AC waveform in most of operating time, not like a TRIAC dimming.

Abstract: An add-on smart controller for an LED lighting device includes a power input port, a power output port, a housing, a control unit in the housing, and at least one control signal receiver in the control unit. A power input of the control unit is connected to the power input port. A power output of the control unit is connected to the power output port. The control signal receiver is configured to receive external control signals. The control unit is configured to activate the power output port to supply output voltage responsive to the control unit receiving an ON signal. The control unit is configured to deactivate the power output port responsive to the control unit receiving an OFF signal.

Abstract: Embodiments of a magneto-optic crystal assembly for use in polarization rotation applications are disclosed. In one aspect, a magneto-optic crystal assembly includes two or more magneto-optic crystals. The temperature and wavelength dependencies of Faraday rotation of these crystals are compensated so that the crystal assembly has both reduced temperature and wavelength dependencies of the polarization rotation angle over broad temperature and wavelength ranges.