Frank Kimpel's research while affiliated with Fibertek and other places

Publications (16)

Article
We report on the development, testing, and initial space qualification of a 1.5-μm, high-power (6 W), high wall-plug efficiency (∼15%), pulse-position-modulated (PPM), polarization-maintaining, fiber laser transmitter subsystem for deep-space laser communication links. Programmable high-order PPM modulation up to PPM-128 formats, with discrete puls...
Conference Paper
We report on the development, testing and initial space qualification of a 1.5-μm, high-power (6W), high wall-plug efficiency (~15%), pulse-position-modulated (PPM), polarization-maintaining (PM), fiber laser transmitter subsystem for deep-space laser communication links. Programmable high-order PPM modulation up to PPM-128 formats, with discrete p...
Article
A Yb LMA fiber amplifier based 1030nm laser transmitter capable of operating with high average power and peak power (∼500W, 9kW) is presented. The prototype, all-fiber, high TRL level laser transmitter is designed to meet all the single aperture requirements of a multi aperture deep space laser beacon system including operation with Nested pulse po...
Conference Paper
A 1um fiber laser outputting high energy (<1mJ) pulse-bursts with high peak powers (<15kW) and narrow linewidth (<300MHz) is an attractive pump source for tunable periodically poled crystal (PPx) based OPA’s which are used in gas sensing, imaging and communication applications. Here a turn-key 1064nm PM Yb-doped fiber amplifier capable of generatin...
Conference Paper
Fibertek has developed a space qualifiable, highly efficient, high power (<5W), fiber based 1.5um laser optical module (LOM). The transmitter achieves 6W average and <1kW peak power out of a 2m long single mode delivery fiber with 8nsec pulses and <6Ghz linewidth. Stimulated Brillouin Scattering (SBS) is managed by precise linewidth control and by...
Article
A Yb LMA fiber amplifier based laser transmitter capable of operating with high average power and high energy (~500W, 1mJ) is presented. The prototype, all-fiber, high TRL level laser transmitter is designed to meet all the single aperture requirements of an eight aperture deep space laser beacon system. The high speed FPGA controlled transmitter s...
Article
Space based laser remote-sensing for Earth observation and planetary atmospheres has traditionally relied on the mature diode-pumped solid-state laser and nonlinear frequency conversion technology. We highlight representative examples, including ongoing space mission programs at Fibertek. Key design issues are highlighted, and the lessons learned f...
Article
We demonstrate highly efficient, 1.5um-fiber-amplifier, optimized for athermal and reliable operation. High efficient operation is sustained for a wide range of pulse-position-modulation (16 to 128-ary PPM) formats with pulse widths varying from 8nsec to 0.5nsec. System achieves 6W average and ~1kW peak power with 8nsec pulses and 3Ghz linewidth. S...
Article
We present a special high spectral resolution lidar (HSRL) by using a novel tunable fiber based transmitter. The transmitter can produce 50μJ pulse energy at 1064nm and >25μJ pulse energy at 532nm with 10 kHz repetition rate, 5ns pulse width, respectively. A key advantage of the transmitter is the frequency-tunability. The laser can be tuned over t...
Article
A kW-class fiber-amplifier based laser illuminator system at 1030nm is demonstrated. At 125 kHz pulse repetition rate, 1.9mJ energy per pulse (235W average power) is achieved for 100nsec pulses with >72% optical conversion efficiency, and at 250kHz repetition, >350W average power is demonstrated, limited by the available pumps. Excellent agreement...
Article
Novel tapered Yb-doped polarization-maintaining (PM) large-mode-area (LMA) fibers were fabricated, with 25/250μm and 40/400μm core/clad at each end, and used in the last stage of a multi-stage Yb-fiber MOPA. The fiber-MOPA is controlled by high-speed FPGA for real-time control of the seed laser diode modulation, electro-optic modulator and acousto-...
Article
KW level fiber based MOPA laser system at 1018-1024nm for uplink deep space communication is developed and characterized. System achieves 5kW peak power (300W average power) with >75% optical conversion efficiency at 1024nm. Experiments with 9-ary PPM pulse format at 500 kHz are presented. Pattern dependent pulse energy variation <10% is achieved u...
Article
We report on the development of a fiber-optic pulsed coherent lidar transceiver for wind-velocity and aircraft wake-vortex hazard detection. The all-fiber 1.5mum transmitter provides up to 560 muJ energy at 25 kHz with 800 ns pulse width (pump limited). Performance simulations indicate wake-vortex hazard signature detection up to ~2.5km range with...
Conference Paper
KW level fiber based MOPA laser system at 1064nm for uplink deep space communication is developed and characterized. System achieves 11.5 kW peak power (600W average power) at 500 kHz (5% duty cycle) with >70% optical conversion efficiency. Experiments using 16-ary PPM format are presented where without pre-pulse shaping >±60% pulse energy variatio...
Article
We demonstrate a multi-channel architecture for nsec pulsed lidar transmitter, scalable to larger channel counts via wavelength- and time-multiplexing in a multi-stage Yb-fiber amplifier. This technology enables lidar systems for topographic mapping missions, requiring much greater spatial coverage and range resolution. We demonstrate prototype har...
Article
We present results on the design, development and initial testing of a fiber-optic based RF-modulated lidar transmitter operating at 532nm, for underwater imaging application in littoral waters. The design implementation is based on using state-of-the-art high-speed FPGAs, thereby producing optical waveforms with arbitrary digital-RF-modulated puls...

Citations

... The intensity modulation/direct detection (IM/DD) mode is generally used in the wireless laser communication. The typical modulation methods include on-off keying [3] (OOK), pulse position modulation [4] (PPM) and digital pulse interval modulation [5] (DPIM) etc. PPM has a higher power utilization and can be better suitable for space optical communication [6]. In 2012, Ke and other scholars compared the performance of various pulse position modulation in wireless laser communication [7]. ...
... Since the development of the 1550-nm erbium (Er)-doped optical fiber amplifier (EDFA) using an indium gallium arsenide phosphide (InGaAsP) semiconductor laser and an Er-doped optical fiber (EDF) [6], various 1550-nm EDFAs and Er-and ytterbium (Yb)-doped optical fiber amplifiers (EYDFAs) have undergone dramatic development [7]. In particular, EYDFAs are crucial for high-power applications, including long-distance optical wireless communications and light detection and ranging (LIDAR) [3], [4]. Recently, Manuscript received December 20, 2019; revised March 23, 2020; accepted April 17, 2020. ...
... TMI is widely attributed to a refractive index (RI) grating formation due to transverse mode beating and coupling between the amplified fundamental mode (FM) and high order modes (HOM). In high power operation, the RI grating has been considered to be induced by thermo-optic effects [4][5][6][7][8][9][10][11][12][13]. At low powers and high gain conditions, on the other hand, TMI has been attributed predominantly to inversion related RI changes [16,17]. ...
... The pump laser is a custom burst-mode Yb fiber laser from Fibertek Inc., based on a master oscillator power amplifier configuration. 38 The pump laser was optimized for high peak power and generated 600 μJ in a burst pulse. Each burst pulse consists of 20 individual 3 ns pulses separated by 85 ns with the individual pulse energies in the burst varying from 2 to 10 μJ. ...
... Cladding-pumped, Yb-free Er fibers look promising, but to-date there is no polarization-maintaining demonstration [10]. A fiber laser for LIDAR using polarization-maintaining, commercial, off-the-shelf ErYb fiber has been demonstrated, but the relatively small effective area of the core made peak power scaling difficult [11,12]. ...
... Ils présentent une robustesse et une simplicité dans la mise en oeuvre remarquable. Il a été largement démontré l'intérêt des fibres optiques pour des systèmes embarqués grâce à leur insensibilité aux vibrations [29]. Cependant la montée en puissance crête de ces lasers, nécessaire pour des études spatiales, est limitée par des effets non-linéaires dans les fibres optiques. ...
... Focusing on OHPAs for space missions, output power exceeding 20 W was experimentally achieved in the United States, and a 6-W class prototype based on the experiments was developed for a planetary exploration mission [3]. In addition, OHPAs for satellites operating in geostationary orbit (GEO) or low Earth orbit (LEO) were also reported [4,5]. ...
... These may ultimately achieve higher wall-plug efficiency. 3,4 However, the OPA clearly provides a convenient light source for the measurement of numerous gases. ...
... The high speed FPGA controlled transmitter supports number of high bandwidth laser transmitter control capabilities including interoperability with JPL's PPM modem, distributed PPM-slot position dependent pre-pulse (arbitrary) shaping at three different points in the amplifier chain (directly modulated DFB laser and two acousto-optic modulators), linewidth (x10GHz) control and depolarization bandwidth control. FPGA based pre-pulse shaping capability is compatible with the open loop PPM pattern dependent pulse amplitude variation reduction algorithm 5,6 . Further more ultra-fast high power pump diode drivers for the final two stages are used for generating the outer nested PPM modulation with (65.536usec slot size) as well as for implementing ultra-fast (<3usec) LOS protection for power stages. ...
... A great number of studies have been conducted from different perspectives to illustrate the characteristics of vortices in various applications. On one hand, many researchers have focused on the development of strategies to avoid the hazard of vortices in past decades [2,[13][14][15][16][17][18][19][20]. On a large scale, tornadoes have been studied experimentally to help improve risk management [1,13]. ...