| 摘要 |
PROBLEM TO BE SOLVED: To easily drastically improve the temperature coefficient of an etalon, and thereby greatly improve optical frequency accuracy. SOLUTION: The etalon 13 functioning as a Fabry-Perot resonator is formed by bonding a quartz crystal bulk A1 to a compensation bulk A2 to form reflection films A3, A4 respectively to opposed faces of both the bulks including the Z-cut surface of the quartz crystal bulk A1. The compensation bulk employs an LiCAF having a characteristic in which a value of (1/n)*(δn/δT)+αbecomes negative (wherein round dindicates the symbol of partial differentiation), wherein n is the refractive index, T is the temperature andαis the linear expansion coefficient, and a ratio of the optical length of the quartz crystal bulk to that of the compensation bulk is approximately set to absolute value ((1/n)*(δn/δT)+α):3×10<SP>-6</SP>. Thus, the temperature characteristics of the etalon 13 are compensated, the temperature coefficient of the etalon 13 can easily and rapidly be improved, and the optical frequency of a semiconductor laser can be stabilized with high accuracy by using the etalon 13 to measure the radiation beam of the semiconductor laser and controlling the optical frequency of the semiconductor laser on the basis of a result of the measurement. COPYRIGHT: (C)2006,JPO&NCIPI
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