| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical module using a graded-index rod lens reduced in insertion loss and reflected return light even if the distance between the rod lens and an optical element is long. SOLUTION: A rod lens having both end surfaces perpendicular to an optical axis C is used as the rod lens 33 having a lens length Z of an optimum pitch with respect to a distance L between the rod lens 33 and a mirror 34 when L is longer than 0.4 mm. The lens length Z is set within a range from 0.21 to 0.1P. Even if L is longer than 0.4 mm, the astigmatisms and comatic aberrations due to slopes are decreased by using the rod lens having both the end surfaces perpendicular to the optical axis C, and then the insertion loss is reduced. The spacing WD between optical fibers 31 and 32 and the rod lens 33 increases, since L is prolonged, and even if the rod lens having both the end surfaces perpendicular to the optical axis is used, the reflected return light is negligible. COPYRIGHT: (C)2004,JPO |
