| 356 / | HD | OPTICS: MEASURING AND TESTING |
| 900 | | INTERFEROMETERS (GO1B 9/02) {3} |
| 901 | DD | .~> Involving fiber optics or integrated optics (GO1B 9/02F) |
| 902 | DD | .~> Involving diffraction gratings (GO1B 9/02G) |
| 903 | DD | .~> Using holographic techniques (GO1B 9/021) |