| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical device capable of executing astigmatic correction, without increasing the number of part items and without changing left and right balance of a wave front in the direction parallel to the active layer of a laser diode. SOLUTION: This optical device has a constitution provided with a base 11, at least one of light receiving elements 15a, 15b, a light emitting element 14 provided on the base, and a spectroscopic means 16 which is arranged at a prescribed distance from the light emitting element on the base, for transmitting emitting light L from the light emitting element, and reflecting return light from the transmission direction to converge it on the light receiving elements. The spectroscopic means 16 has a first refractive index members 16b, 16f and a second refractive index member 16d arranged in a region held between two planes 16c, 16e parallel to each other in the first refractive index member and having a lower refractive index than the first refractive index member. The two planes 16c, 16e parallel to each other, which are boundary faces between the first refractive index member and the second refractive index member, are arranged at an inclined angle with respect to the emitting light L from the light emitting element. |
