Abstract

Reducing the spectral linewidth of laser diodes is important for fiber-optic sensors, especially optical passive ring-resonator gyroscope (OPRG).¹ For example, the laser with the linewidth narrower than several tens of kHz is required to detect the rotation rate of 10⁻⁷ rad/s.² To obtain narrow linewidh, external-cavity laser diodes are usually constructed because of their simple structure and excellent spectral purity.³⁾ A special configuration of the external-cavity laser diode, that is, a semiconductor-optica1 fiber ring (SOFR) laser, has potential advantages as follows.

© 1986 Optical Society of America