Characteristics of 20 year old iodine cell and compact iodine stabilized laser

Spectral quality and reliability of four kinds of¹²⁷ I ₂ cells for an wavelengtn standard were investigated. A 20 year old 10 cm long sealed off iodine cell has shown its long life and had sufficient absorption characteristics comparable to the newly made three cells in regard to spectral line width and signal-to-noise ratio of the absorption signal. A dispersion of absolute frequencies of the three cells including the 20 year old cell is in a range of 35 kHz, which is equivalent to a frequency reproducibility of 7.4X10^-11. A compact iodine stabilized 633 nm He-Ne laser with a 23 cm long resonator and 4 cm iodine cell has been developed. Its frequency stability has been estimated to be 9X10^-13 by the Allan deviation at integration time of 4000 s. The laser supplies 14 wavelength standards being locked at iodine absorption lines from a ton.