Share Email Print
cover

Optical Engineering

Characterization of a diode double-end pumped Nd:YVO4 laser for high-bit-rate free-space and intersatellite communications
Author(s): S. K. Sudheer; N. Venugopalan Pillai; V. P. Mahadevan Pillai; V. Unnikrishnan Nayar
Format Member Price Non-Member Price
PDF $20.00 $25.00

Paper 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:YVO4 laser 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)

Paper Details

Date Published: 1 October 2007
PDF: 8 pages
Opt. Eng. 46(10) 104201 doi: 10.1117/1.2790027
Published in: Optical Engineering Volume 46, Issue 10
Show Author Affiliations
S. K. Sudheer, Vellore Institute of Technology (India)
N. Venugopalan Pillai, Kerala Univ. (India)
V. P. Mahadevan Pillai, Kerala Univ. (India)
V. Unnikrishnan Nayar, Kerala Univ. (India)


© SPIE. Terms of Use
Back to Top