Simultaneous Measurements for Tunable Laser Source Linewidth with Homodyne Detection

Abstract

The linewidth characteristics of a commercial tunable laser source (TLS) are measured experimentally employing self-homodyne detection method. Three linewidths are obtained at different operating wavelengths with two optical fiber delay lengths. It is found that a slightly higher values are obtained with a longer length of the delay fiber. The long of (50 km and 25 km) of single mode fiber SMF is enough to provide delay for the self-homodyne linewidth measurement.

Linewidth Measurement of a Narrow-Linewidth Laser: Principles, Methods, and Systems

“…Additional optical transmission losses and 1/ f noise are inevitable for excessively long delay optical fibers, resulting in spectrum broadening and phase noise jitter. Therefore, researchers have proposed MI-type structures [ 34 , 35 , 36 , 37 ] and gain-compensated cyclic structures [ 38 , 39 ] based on MZI-type structures.…”

Laser Linewidth Measurements Using Self-Heterodyne Detection with Total-Reflected Delay Line

“…With the development of the optical communication technology, more and more tunable laser source (TLS) has been developed used in the measurement system [1][2][3]. Many applications require laser sources that offer a narrow linewidth [4]. The linewidth has become the bottleneck of limit the development in such applications as coherent optical communication, optical precision metrology, and other aspect.…”