Phase locking of optical sources and impact on system
Example 1 - Phase difference between lasers
Two free-running lasers, each with linewidth 250 kHz, are used as the signal laser and the LO in a coherent optical transmission system. What is the rms increase in the phase difference between the laser over a time interval of 1 µs?
Example 2 - OPLL with delay
A prototype first-order OPLL is constructed from optical components with fibre pigtails. The total length of fibre in the loop is 2 m. What is the maximum loop bandwidth if the propagation delay through the fibre is the dominant delay?