The issue of excess14 noise is of interest with respect to the broadband optical sources commonly used in interferometric fiber optic gyroscopes because it can limit the ultimate sensitivity of the device. Excess noise has been studied in superluminescent diodes (SLD's) by Yurek, et .al. 1 and in an Erbium doped fiber by Morkel, et.al.2 . The latter group also presented a simple model for the excess noise and demonstrated a quantitative fit with the linewidth of their source. In this letter we report measurements of excess noise in three potential fiber gyroscope sources, SLD's at 0.83 pm and 1.3 .tm and a superfluorescent Nd doped fiber at 1 .06 pm. These noise measure-ments are shown to be in good agreement with the model of Ref. 2. The model for excess noise is used to calculate the random walk coefficient due to shot and excess noise in a interferometric fiber gyro to demonstrate the impact excess noise in these sources will have on such a gyroscope. We show that the gyros utilizing SLD sources are just barely impacted by excess noise due to their limited output power (1-3 mW in a single mode fiber). The fiber source at 1 .06 tim, with its higher potential output power, will likely be limited by excess noise.

Date Published: 1 February 1991
PDF: 6 pages
Proc. SPIE 1367, Fiber Optic and Laser Sensors VIII, (1 February 1991); doi: 10.1117/12.24732

Published in SPIE Proceedings Vol. 1367:
Fiber Optic and Laser Sensors VIII
Ramon P. DePaula; Eric Udd, Editor(s)