We report the experimental demonstration of tunable optical frequency division based on an efficient, one-step parametric downconversion process in a potassium titanyl phosphate (KTP) optical parametric oscillator (OPO). Our compact OPO generated two nearly degenerate subharmonic outputs that can be tuned over a 1.5 THz range in the signal-idler beat frequency by crystal angle tuning and cavity length scanning. We achieved continuous tuning of the beat frequency over a range of 0.5 GHz through the use of temperature and electro-optic tuning of the KTP crystal. A tunable optical frequency divider was realized by phase locking the signal- idler beat frequency to an external microwave frequency source, which yielded a beatnote linewidth at the sub-Hz level. The output frequencies of the phase-locked OPO were therefore precisely controlled by the tunable microwave source and the pump frequency. Characteristics of three different OPO cavity designs and their operations are discussed.

Date Published: 30 April 1993
PDF: 7 pages
Proc. SPIE 1837, Frequency-Stabilized Lasers and Their Applications, (30 April 1993); doi: 10.1117/12.143695

Published in SPIE Proceedings Vol. 1837:
Frequency-Stabilized Lasers and Their Applications
Y. C. Chung, Editor(s)