Abstract: A method for arranging a high power fiber laser system includes spiraling an active fiber in a housing with a diameter of spiral gradually decreasing towards the center of the housing. The method further includes coupling the opposite free ends of the spiraled active fiber to respective passive fibers providing optical communication between the active fiber and discrete components. Thereafter, the passive fibers with the discrete components are arranged next to inner spirals of the active fiber.

Abstract: A method and apparatus are operative to control the desired level of population inversion in a gain medium having an amplified spontaneous emission (ASE) spectrum which is characterized by distinct short- and long-wavelength regions. The control is realized by the apparatus configured to determine a relationship between the regions of the ASE spectrum represented by respective frequencies which are filtered by respective frequency discriminators. The apparatus includes a controller operative to process the filtered frequencies by determining a relationship between amplitudes of the respective filtered frequencies which represents a measured level of population inversion. Upon mismatch between the measured level and desired level of the population inversion, a control signal is coupled into a pulse generator or pump or both. In response, the pulse generator may output a pulse, or/and the pump may he completely shut down to lower the level of the measured inversion.

Abstract: A high power fiber laser system emitting a substantially diffraction limited beam with a Gaussian intensity profile includes a single mode (“SM”) neodymium fiber pump source outputting a SM pump light; a seed laser operative to emit a SM signal light at a wavelength greater than that of the pump light; a SM DWM receiving and multiplexing the SM pump and signal lights. The disclosed system further includes a booster fiber amplifier which is configured with a frustoconically-shaped ytterbium (“Yb”) doped core receiving the pump and signal lights and configured with a small diameter input end which supports only a SM and a large diameter output end which is capable of supporting the SM and high order modes (:HOM”). The booster further has a cladding surrounding and coextending with the core, the core being configured for having intensity profiles of respective SMs of pump and signal lights overlap one another so that an overlap integral substantially equals to one (1) along an entire length of the core.

Abstract: A method for arranging a high power fiber laser system includes spiraling an active fiber in a housing with a diameter of spiral gradually decreasing towards the center of th housing. The method further includes coupling the opposite free ends of the spiraled active fiber to respective passive fibers providing optical communication between the active fiber and discrete components. Thereafter, the passive fibers with the discrete components are arranged next to inner spirals of the active fiber.

Abstract: A method for contactless laser welding of a plurality of sheets of material stacked upon one another includes simultaneously delivering a laser beam and a stream of fluid through a laser head and further through an end cap which is removably mounted to the laser head. The end cap is configured with a stationary cylinder, which is coupled to the laser head, and a piston movable relative the cylinder. The piston moves in response to a pressure differential generated by the fluid in chambers above and below the piston. Once the pressure equilibrium is reached between the chambers, the pressure in the chamber below the piston is sufficient to reliably press the sheets of material against one another during a laser welding operation.

Abstract: An ultra-long fiber-optic transmission system is configured in accordance with the current telecom standards and particularly advantageous for transmission data at a long distance which may exceed 400 km between adjacent nodes. The disclosed system has at least one intermediate amplifying node provided with a supervisory optical channel (SOC) which carries information between spaced nodes about the multi-wavelength optical signal as well as remote conditions at the optical terminal or regeneration site. The SOC comprises a transponder operative to select the direction in which an optical supervisory signal OSS, carrying information about the fiber break and malfunction of WDM channels, is transmitted along the SOC. The transponder further includes a receiver operative to measure the power of incoming OSS signal, which is indicative of the power of the transmitted and amplified WDM signal, and a Raman controller.

Abstract: A WDM fiber optic communication system is operative to transmit WDM signals between multiple nodes. Each node has a booster EDFA, and in-band and out-of-band supervisory channels monitoring the integrity of a link by generating and detecting respective in-band and out-of-band control signals. The booster EDFA receives the multiplexed WDM and IB signals and generates an output signal carried by fibers between the nodes. The booster EDFA switches from an automatic gain control regime upon detecting of at least one of the IB and OB control signals to an automatic power control regime upon loss of both IB and OB control signals. The output signal of the EDFA in the AGC regime has a high power sufficient for transmitting the WDM and IB signals, and has a low power in the APC regime sufficient for transmitting only the IB control signal.

Abstract: An ultra-long fiber-optic transmission system is configured in accordance with the current telecom standards and particularly advantageous for transmission data at a long distance which may exceed 400 km between adjacent nodes. The disclosed system has at least one intermediary amplifying node provided with a supervisory optical channel (SOC) which comprises a transponder operative to select the direction in which a supervisory channel signal (SCS), carrying information about the fiber break and malfunction of WDM channels, is transmitted along the SOC. The transponder further includes a receiver operative to measure the power of incoming and a Raman controller coupled to the receiver and to either turn or turn off a pump of Raman amplifier based on determination of whether the measured power of the SCS is lower than or at least equal to a reference value. The transponder is further configured with a transmitter configured as a fiber laser which operates in at least two modes.

Abstract: A wavelength division multiplexing (WDM) fiber optic communication system is operative to transmit WDM signals between multiple nodes. Each of the nodes has a booster EDFA, and in-band (IB) and out-of-band (OB) supervisory channels operative to monitor the integrity of a transmission link by generating and detecting respective in-band and out-of-band control signals. The booster EDFA is operative to receive the multiplexed WDM and IB signals and generate an output signal carried by a plurality of fiber-optic cables between the nodes. The booster EDFA is operative to switch from an automatic gain control regime upon detecting of at least one of the IB and OB signals to an automatic power control regime upon loss of both IB and OB signals. The output signal of the EDFA in the AGC regime has a high power sufficient for being transmitted the WDM and IB signals, and has a low power in the APC regime sufficient for transmitting only the IB signal between the nodes.

Abstract: Apparatus and method for equalizing a multiplicity of amplifier optical output signals comprised of a combined broadcast optical signal and a narrowcast optical signal having different bands of wavelengths of light by adjusting the power output level of at least one the signals in response to an amplified sample of the signal. A light switch or attenuator and a sensor for determining whether a transmission fiber is in place is connected to each of the multiplicity of optical output signals to allow the optical output signals to be turned on and off for maintenance and repair.

Abstract: Apparatus and method for equalizing a multiplicity of amplifier optical output signals comprised of a combined broadcast optical signal and a narrowcast optical signal having different bands of wavelengths of light by adjusting the power output level of at least one the signals in response to an amplified sample of the signal. A light switch or attenuator and a sensor for determining whether a transmission fiber is in place is connected to each of the multiplicity of optical output signals to allow the optical output signals to be turned on and off for maintenance and repair.