International comparisons of He-Ne lasers stabilized with¹²⁷I₂at   = 633 nm (July 1993 to September 1995). Part V: Comparison of Asian-Pacific and South African lasers at   = 633 nm

Abstract

This paper reports the fifth set of results of a series of grouped laser comparisons from national laboratories undertaken by the Bureau International des Poids et Mesures (BIPM) at the request of the Comité Consultatif pour la Définition du Mètre (CCDM, now the Consultative Committee for Length, CCL), during the period July 1993 to September 1995. The results of this comparison, involving six lasers from five countries and the BIPM, meet the goals set by the CCDM in 1992 and adopted by the Comité International des Poids et Mesures (CIPM) the same year. The standard uncertainty (1 ) of the frequency of the He-Ne laser stabilized on the saturated absorption of 127 I 2 at λ 633 nm is reduced to a level of 12 kHz (2.5 parts in 10 11 ) when the lasers compared meet the recommended values of the parameters.The lasers were first compared with the BIPMP3 or the CSIRO1 lasers, with all the lasers set to the parameter values normally used in each laboratory; the results ranged from -48.3 kHz to 13.8 kHz. After checking and readjusting the values of all the parameters, the range was reduced to -14.7 kHz to 10.4 kHz. Under the latter conditions, the average frequency difference of the group of lasers with respect to the BIPM4 laser was -0.5 kHz with a standard uncertainty (1 ) of 8.5 kHz. The best relative frequency stabilities, with Allan standard deviations of about 3.5 parts in 10 12 and 3.5 parts in 10 13 , were observed with sampling times of 8 s and 2048 s, respectively.

International comparisons of He-Ne lasers stabilized with127I2at 633 nm (July 2000). Part X: Comparison of INMETRO (Brazil), INTI (Argentina), NRC-INMS (Canada), CENAM (Mexico), and BIPM lasers at 633 nm

“…This is the tenth in a series of reports describing the results obtained during an extensive programme of laser comparisons carried out over the period July 1993 to March 2001 [1][2][3][4][5][6][7][8][9][10].…”

Effect of frequency modulation amplitude on Iodine stabilized He-Ne Laser, at λ ≈ 633nm

“…The effect of modulation amplitude on the d, e, f, g components of transition 11-5, R(127) of 127 I 2 was determined by (9,10,11) and tabulated in tables (2, 3 and 4). Where ∆f/fω is the modulation width factor, L is the slope of a linear fit to the data points and s the estimated standard uncertainty of one measurement.…”

“…The absolute accuracy of iodine stabilized laser is limited by normally controlled in iodine stabilized laser and can influence the determination of the correct center frequency of the hyperfine components is the frequency modulation amplitude. The effect of modulation amplitude on the d,e, f, g components of transition 11-s, R(127) of 127 I 2 : ∆f / f ω is the modulation width factor, L is the slope of a linear fit to the data points and s the estimated standard uncertainty of one measurement as found by (9,10,11) was tabulated in tables (2, 3, and 4).…”

International comparisons of He-Ne lasers stabilized with127I2at = 633 nm (July 1997). Part VIII: Comparison of NIM (China), NRLM (Japan), KRISS (Republic of Korea) and BIPM lasers at = 633 nm

“…comparisons carried out during the periods July 1993 to September 1995 and March 1997 to July 1997 [1][2][3][4][5][6][7][8].…”

“…Earlier bilateral comparisons 2.0 1.3 0.5 0.9 0.9 Radius of curvature/cm have been carried out between each of these national laboratories and the BIPM; their results have been reported elsewhere by the NIM [10], the NRLM [11] and the KRISS [12]. An Asia-Pacific comparison was carried out at the CSIRO in July 1995 [5], but for different reasons the NIM and the NRLM were unable to participate.…”