Abstract: Disclosed herein is a duplicated light source module constructed so that rays of light emitted from two light sources pass through one lens and then enter one optical fiber through a birefringent element. This module is useful when a light source in an optical transmitter is intended to be duplicated or when a high-power pumping source in an optical fiber amplifier is required.

Abstract: A ball lens assembly constructed of a lens holder formed with a press-fit hole having a circular section and a ball lens press-fitted with the press-fit hole of the lens holder. The lens holder is formed by sintering stainless steel powder. As the lens holder is formed by sintering, a force for press-fitting the ball lens into the lens holder can be suppressed to thereby effectively prevent breakage of the ball lens.

Abstract: A semiconductor laser module comprises a semiconductor laser chip for emitting a laser beam, a collimator lens for collimating the laser beam to a collimated beam, a focussing lens for focussing the collimated beam, and an optical fiber having an inclined input face to which the laser beam from the focussing lens in input. The focussing lens is arranged in such a manner that the optical axis of the collimated beam incident on the focussing lens is deviated from a center axis of the focussing lens, and the optical fiber is arranged in parallel to the collimated beam in such a manner that the laser beam is incident on an optical axis of the optical fiber.