Fiber laser systems for space lasercom and remote sensing

Abstract

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 from a multi-disciplinary design process addressing the space-qualification requirements.Fiber laser/amplifier system provides an agile optical platform for space based laser applicationsspace lasercom, space-based Earth (or planetary) remote sensing, and space-based imaging. In particular we discuss ongoing efforts at Fibertek on a space-qualifiable, high-performance 1.5-m Er-doped fiber laser transmitter for inter-planetary lasercom. Design and performance for space qualification is emphasized. As an example of an agile laser platform, use of above fiber laser/amplifier hardware platform for space based sensing of atmospheric CO 2 is also highlighted. Downloaded From: http://proceedings.spiedigitallibrary.org/ on 05/19/2015 Terms of Use: http://spiedl.org/terms Proc. of SPIE Vol. 8876 88760E-2 Downloaded From: http://proceedings.spiedigitallibrary.org/ on 05/19/2015 Terms of Use: http://spiedl.org/terms Radiation pattern Gamma-Radiation Test Proc. of SPIE Vol. 8876 88760E-7 Downloaded From: http://proceedings.spiedigitallibrary.org/ on 05/19/2015 Terms of Use: http://spiedl.org/terms radiation dose 26,27 . However, newer material compositions of rare-earth-doped glass fibers are being developed, that have largely eliminated this radiation susceptibility 28,29 . Ongoing work at Fibertek is focused on such fiber-MOPA systems, that are targeted for initial space qualification tests of up to 10W of average power, for space laser communication and space-missions for Earth atmospheric sensing. CONCLUSIONSignificant advances in high-reliability fiber-optic telecom component technology, coupled with high-power performance spurred by the demands from high-power industrial fiber laser markets, is enabling the design, development and qualification of fiber laser/amplifier based transmitters for multiple space based remote-sensing and optical communication missions. A common fiber-MOPA architecture helps in the development cost for a space qualified laser transmitter. Such laser transmitters are scalable to higher average powers, need no special thermal management, and are inherently robust and alignment free compared to the currently qualified diode-pumped solid-state laser technology. Ongoing work at Fibertek has produced promising results, and space qualified fiber laser/amplifier systems are expected to mature within the next 2-3 years. Fibertek acknowledges support from various NASA programs, for the results highlighted in this paper.

Heat treatment to regulate bismuth valence toward enhanced radiation resistance in barium gallo‐germanate glass

“…Fiber laser has good beam quality, high laser efficiency, good heat dissipation, stability, and high reliability, which has been widely used in the fields of photocommunication, remote sensing, laser surgery, highresolution spectroscopy, coherent laser radar systems, and so on. [1][2][3][4] However, when fiber lasers are used in a high-energy ray irradiation environment, such as space exploration, [5][6][7] laser sensing, 8 and nuclear industry, 9 the darkening of the glass fibers appears, which is commonly referred to as radiation-induce darkening (RD) phenomenon. RD has been recognized as a serious issue for the utility of laser devices in the radiation environment, which not only gives rise to optical excess loss from ultraviolet to visible even down to near-infrared spectral region 10,11 but also causes continuous decrease in the output power, efficiency, lifetime, and reliability of these fiber laser systems.…”

High-power ns-pulse fiber laser sources for remote sensors

“…Higher PRF/average-power operation in bulk SSLs is typically hindered by beam quality (BQ) degradation induced by thermo-optic effects. On the other hand, photon counting sensors operating at high PRF of 10 s to 100 s of kHz can benefit from low-SWaP optical sources emitting pulse energy in the 0.1-1 mJ range, corresponding to average powers of 10 s to 100 s of watt [14][15][16][17][18].…”

Raman shifting in gas filled hollow core fiber amplifiers

“…[6][7][8][9][10][11][12][13][14][15][16][17] Industry applications have been identified for improved 1.5 µm laser sources. 18 Mature 1.06 µm laser sources can be Raman shifted in a methane or deuterium filled HCF to ∼1.55 µm utilizing the vibrational Raman shift corresponding to a symmetric molecular stretch. Direct analysis of prior deuterium based experiments is difficult due to the variations in pump wavelengths, pump configurations, and Raman shifts utilized.…”