Abstract

The conventional method for a range resolved lidar is to use a high peak power, pulsed laser source, and either direct or optical heterodyne detection of the radiation scattered from aerosols in the atmosphere. Time of flight is then used to make range resolved measurements. This technique works well and has been in use for quite some time. However, if a continuous wave (cw) laser source could be used, a lighter, smaller, more reliable system would result and the use of laser diodes becomes more feasible. With a cw source, in order to achieve range resolved measurements, some form of modulation must be used. Our approach is to use a pseudo random code (PRC) modulation of the optical phase of the cw laser source.¹ The PRC modulation allows path resolved measurements through the use of a correlation-type receiver.

© 1995 Optical Society of America