Comparative study of the performance of semiconductor laser based coherent Doppler Lidars
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Comparative study of the performance of semiconductor laser based coherent Doppler Lidars
- Author:
Peter John Rodrigo and Christian Pedersen
In this work, we demonstrate that two SL sources, namely (1) a 1550-nm monolithic master-oscillator-power-amplifier (MOPA) SL and (2) a 1470-nm external-cavity tapered diode laser (ECTDL), have great potential in competing with expensive FLFA sources used in today’s commercial CDLs. In the following section, we show that the MOPA-SL and the ECTDL are capable of achieving high output power up to 0.6 W and 0.5 W, respectively – the power levels required in most wind Lidar applications. We also show in section 3 the measured spectral characteristics of both SL sources depicting single-frequency operation and high side-mode suppression ratio (SMSR > 40 dB), i.e. performance at par with that of a Fiber Laser. In section 4, we present our measurements that quantitatively compare the relative intensity noise (RIN) properties of the MOPA-SL and the ECTDL versus that of a FL. Among the two SL sources, the monolithic MOPA-SL is found to be more reliable and even better in terms of RIN characteristics when compared to the FL. Furthermore, we present in section 5 the delayed self-homodyne measurement of the MOPA-SL’s linewidth to deduce the potential range capability of a CDL based on this light source. Finally, in section 6, we summarize the comparative study performed in this work and discuss some future extensions we plan to undertake.
