[OPTICAL REVIEW Vol. 18, No. 3 (2011) 287-292]
© 2011 The Japan Society of Applied Physics

Laser Diode Beam Shaping by Optical Interference

Takehiro FUKUSHIMA, Koichiro SAKAGUCHI, and Yasunori TOKUDA

Department of Communication Engineering, Faculty of Computer Science and System Engineering, Okayama Prefectural University, Soja, Okayama 719-1197, Japan

(Received December 2, 2010; Accepted February 23, 2011)

We recently proposed a novel beam shaping technique that employs Lloyd's mirror interference. In this study, we apply this technique to three commercial laser diodes: laser diodes used for optical pumping of solid-state lasers, for laser beam printers, and for laser displays. The elliptical output beams from these laser diodes could be transformed into nearly circular beams by inserting a mirror-polished GaAs substrate below the active layer of each laser diode and adjusting its height. The experimentally observed far-field patterns were predicted fairly well by numerical calculations based on Huygens' integral. We confirmed that our beam shaping technique is applicable to laser diodes with various wavelengths and vertical beam divergence angles. We also describe the monolithic configuration of the beam shaping system, which can be fabricated by dry etching.

Key words: laser diodes, beam shaping, Lloyd's mirror interference, beam divergence angle, mirror-polished semiconductor substrate