SIMULATION OF AN ASTIGMATIC FOCUS ERROR SIGNAL SYSTEM TO ANALIZE DESIGN PARAMETERS

AGUILAR, ANDRÉS DANIEL; TORGA, JORGE ROMÁN

Pucon

Congreso; IX Reunión Iberoamericana de Óptica y XII Reunión Iberoamericana de Óptica, Láseres y Aplicaciones; 2016

Red Iberoamericana de Òptica

The Focus Error Signal technique (FES) has been extensivelyused by the consumer electronics industry inoptical media drives which allowed for an impressivesize and cost optimization since the 1970s [1].Later on this technique proved to be an interesting alternativefor vibration, displacement and topographymeasurements [2][3][4], offering high spatial resolutionand ample bandwidth, combined with contact freecapability. Most experimental setups found on literatureare based on the astigmatic method, composed of acollimating lens, objective, astigmatic lenses and a fourquadrant segmented sensor. While this configuration isrelatively simple, there is little information available onthe relationship between the system?s response and itscomponent?s characteristics [5].Here we present a simulation of the FES based on thesetup shown in Figure 1, with the objective of analysingits working and how the characteristics of the variousoptical components influence the system?s range andspatial resolution. An analysis of the FES properties isalso made regarding its shape, amplitude, symmetryand linearity within the interval of interest.To achieve this, a software tool was developed to calculatethe focus signal for different configurations andsystem parameters. Fig. 2.