Abstract

In the recent years, the industrial use and production of semiconductor lasers have increased drastically, and for many applications the laser linewidth is a crucial performance and cost determining parameter. As originally purposed by Mercer [1], due to the presence 1/f frequency noise, the laser linewidth determined using a self-heterodyne measurement is dependent on the delay length used in the setup. However, many laser manufacturers still specify laser linewidth without indicating the corresponding delay length, resulting in incomplete information for the potential users/buyers of these products. In this presentation, we will demonstrate, experimentally, that the linewidth of a laser diode (LD) dominated by 1/f frequency noise increases with the self-heterodyne delay length (see setup in Fig. 1), and compare it with predictions derived from the theoretical model provided by Mercer [1]. Furthermore, we will relate our results to remote sensing applications, where laser linewidth is a crucial laser parameter that determines both the price and the performance of the instrument.

© 2015 IEEE