A 633 nm iodine-stabilized diode-laser frequency standard

An extended-cavity diode laser has been stabilized to hyperfine components of the 6-3, P(33) transition of the B-X system of I-127(2) at 633 nm, and i ts performance evaluated by comparison with an iodine-stabilized He-Ne lase r. The Allan standard deviation follows a slope of 3.8 x 10(-11) tau(-1/2), reaching a minimum of 1.7 x 10(-12) at 500 s, and the reproducibility of t he diode laser locked to component b(21) has been determined to be 7 kHz (s tandard uncertainty) corresponding to a fractional uncertainty of 1.5 x 10( -11). In addition, the influence of modulation depth, iodine pressure and a xial power density on laser frequency has been investigated. Complete hyper fine interval sets and absolute frequency determinations of component b(21) are presented for modulation depths of 2 MHz and 6 MHz.