Multi-Beam Read-Verifying Optical Head for Parallel Recording
- 1 November 1993
- journal article
- Published by IOP Publishing in Japanese Journal of Applied Physics
- Vol. 32 (11S)
- https://doi.org/10.1143/jjap.32.5406
Abstract
A five-beam read-only optical head using a holographic beam splitter has been developed for instantaneous read-verification of parallel data recording. The holographic grating made of photo-resist film splits a 680-nm laser beam into five diffracted beams and an interval angle of 4 mrad. The average diffraction efficiency of the beams is about 13% and their spot diameters are 1.05±0.03 µm within a 70-µm image circle. A newly designed objective lens system composed of an aspherical lens and a chromatic lens can compensate 680 nm to 780 nm of chromatic aberration of wavelength to less than 0.4 µm. The carrier to noise (C/N) ratio of a 1.53-µm-pitch voltage-controlled frequency oscillation (VFO) signal is 49 dB, which is sufficient for magneto optical (MO) disk data retrieval.Keywords
This publication has 1 reference indexed in Scilit:
- High-Speed Magneto-Optic Disk Drive with Overwriting and Read-Verifying FunctionsJapanese Journal of Applied Physics, 1992