The Hewlett Packard model 5525A Laser system was introduced in the 1971 catalog Supplement "Electronics for Measurement Analysis Computation".    The system is described on page 31, consisting of a laser head and display without citing specific model numbers.   The overall package style and function were very much the same as the later 5526 model.  The main difference is that the interferometer optics were built into the head, requiring only a retroreflector to complete the optics complement.  Options were limited to error plotting, recording , automatic compensator and a beam bender.   Basic linear interferometer system price: $11,500.  Please click here to view the 1971 catalog supplement page.

The very next year, 1972, HP introduced the 5525B system .  They figured out that the bulky laser head very much got in the way with the interferometer internally mounted, so it was brought outside as a separate component - the 10565A "magic cube" remote interferometer.   This also got the heat source away from the measurement path, eliminating a potential compensation problem.  However, it retained potential "dead path" error potential intrinsic with this type of interferometer.  The 5510A automatic compensator with air temperature and humidity and material temperature sensor were introduced.  A X10 resolution extender was made available.  Other options remained as before.  Basic linear interferometer system price: $13,950.  Please click here to view the 1972 catalog page.

1973 was a big year for HP with the introduction of the HP-35 handheld calculator and the 5526A Laser Interferometer, as well as the 5501A system intended to be installed into OEM equipment.  The basic configuration was the same, but angular and straightness optics options were offered.   Also, a single beam interferometer, second axis add-on and plane mirror conversion kit were made available.  A printer was available, but no computerized system yet. Basic linear interferometer system price: $12,400.  Click here to view the 1973 catalog page.

1975-1980 were the next years of significant change for the 5526A system with the succesive introduction of calculator systems based on the new 9820/9821/9825 calculators.  The options remained the same otherwise.  Basic linear interferometer 1975 system price: $14,645.  The calculator option included all displacement and geometric options for an extra $32, 215.  Click here to view the 1975 catalog pages.   Click here to view the 1976 catalog page.  Click here to view the 1980 catalog page.

1984 was the end of the line for the 5526A system with the introduction of the 5528A replacement.  The operating principles remained the same, but the packaging changed significantly.  This evolution continues, with the present day 5529A Dynamic Calibrator system.