Waveguide Laser for High Data Rate Deep Space Communications

Deep space optical communications requires a laser source and modulation technique for high data bandwidth with low power consumption, diffraction-limited beam quality, and the absolute minimal size/weight. Optical fibers are compact and can efficiently amplify high data rate diode lasers, but do not provide the peak power required for detection over deep space transmit distances. Bulk diode-pumped solid-state lasers can produce the required Q-switched pulse energies, but are not as efficient or robust as guided-wave lasers. Furthermore, bulk lasers require a high voltage Q-switch to accurately time the laser pulses for pulse-position modulation (PPM) formats. Coherent Technologies, Inc. has recently discovered a new waveguide laser geometry that allows TEM00 operation in a multi-transverse mode waveguide capable of high power operation. This geometry is exceptionally compact/lightweight and capable of high conversion efficiency as is typically achieved in fiber lasers. Furthermore, this same technology can be applied to create low voltage ( 15 V) Q-switches or phase modulators resulting in a nearly monolithic optical communications transmitter. The waveguide laser transmitter is compatible with a variety of data encoding formats, could be used with direct or coherent detection receivers, and will be capable of data rates in excess of 10 Mbps.