Surface emission laser with current narrowed layer - has narrowed layer material with forbidden band width larger than that of active region and adjacent cladding layer.

摘要

A first Bragg reflecting mirror (4) comprising a multilayer semiconducting film is formed on a semiconductor substrate (1). The active layer (6, 7, 8) lies between a second (9) and first (5) cladding layer which is formed on the mirror. The circuit narrowing layer (10) is formed on the second cladding layer and has a gap (12) into which a covering third cladding layer (13A) lies. The active region has a single or multiple quantum well structure. The current narrowing layer and both the first and third cladding layers are semiconductors of differing type. The upper surface of the third layer includes a step between the region of the circuit narrowing layer and the region of the gap. The second Bragg reflecting mirror (16) comprises another multilayer on this third layer. ADVANTAGE - Easy control of circuit narrowing region in mfr, improved injection current efficiency and improved emission efficiency.