Characterization of a diode double-end pumped Nd:YVO4 laser for high-bit-rate free-space and intersatellite communications

S. K. Sudheer; N. Venugopalan Pillai; V. P. Mahadevan Pillai; V. Unnikrishnan Nayar

doi:10.1117/1.2790027

1 October 2007 Characterization of a diode double-end pumped Nd:YVO₄ laser for high-bit-rate free-space and intersatellite communications

S. K. Sudheer, N. Venugopalan Pillai, V. P. Mahadevan Pillai, V. Unnikrishnan Nayar

Author Affiliations +

Optical Engineering, Vol. 46, Issue 10, 104201 (October 2007). https://doi.org/10.1117/1.2790027

Abstract

Interorbit links, intersatellite links, and deep space missions are certain key applications of free-space optical communication links. For efficient and better signal propagation ensuring minimum possible bit error rate (BER) and maximize signal-to-noise ratio (SNR), the laser source used for carrying information should be one in which the laser power and beam quality do not degrade due to vibrations, shock, and thermal cycling. As part of our attempt to design an efficient and suitable laser source for optical free-space communication, a diode double-end pumped and Q-switched Nd:YVO₄laser is designed and fabricated. The thermally induced lens in the laser crystal brings the flat-convex cavity into geometric stability. A slope efficiency of 58.38% is observed in continuous wave (CW) multimode and 40.49% is observed in CW TEM₀₀ mode operation, which is sufficiently high for free-space optical communication. A minimum pulse width of 7.3 ns is observed corresponding to a peak power of 63.01 kW at 20 kHz. It can be seen that at lower Q-switch frequencies, the pulse width is short and the energy per pulse is high, whereas at higher Q-switch frequencies, the energy per pulse is low and the pulse width is long but the average power is high. The peak power increases with the absorbed pump power, similar to a lamp-pumped Nd:YAG laser. The maximum pulse energy observed is 430 μJ at 10 kHz. Below 20 kHz, no further increase in pulse energy is observed due to the lower lifetime of the upper laser level (~90 to 100 μs) of Nd:YVO₄ crystal. Changes in the laser beam profile with pump power have been studied. The major advantage of the Nd:YVO₄ crystal is the ability to retain short pulse width even at higher Q-switch frequencies like 100 kHz, which makes this laser suitable for ultrahard material processing at higher Q-switch frequencies.At full pump power, the pulse width varies from 7.3 ns at 20 kHz to 19.5 ns at 100 kHz.(partial abstract)

©(2007) Society of Photo-Optical Instrumentation Engineers (SPIE)

Citation Download Citation

S. K. Sudheer, N. Venugopalan Pillai, V. P. Mahadevan Pillai, and V. Unnikrishnan Nayar "Characterization of a diode double-end pumped Nd:YVO₄ laser for high-bit-rate free-space and intersatellite communications," Optical Engineering 46(10), 104201 (1 October 2007). https://doi.org/10.1117/1.2790027

Published: 1 October 2007

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