Abstract

At the present time active homodyne compensation using piezoelectric cylinders appears to be the only detection scheme usable In fully packaged fiber-optic interferometer systems.¹ However, the piezoelectric (P/Z) cylinder introduces a number of problems, namely, (1) an upper frequency response limited by the circumferential resonance of the P/Z cylinder, (2) the weight and size of the P/Z cylinder, (3) problems associated with the reset of the compensator. In this paper we give details of a simple method of keeping the interferometer in quadrature by tuning the emission frequency of the laser diode source by changing the drive current of the laser, thus eliminating the P/Z cylinder. The device can be operated in both the high- and low-gain modes and should allow a flat response (±1 dB) in the high-gain mode from dc to 100 kHz.

© 1982 Optical Society of America