Nec Corporation

Hiroaki Chida

Yoshiyasu Ueno

To provide a low-cost and fine-property bidirectional optical transmitting/receiving module and the like, which include a de-multiplexing device that uses a V-letter shaped optical waveguide and a dielectric multilayer filter. Formation of an end face where the dielectric multilayer film is formed and separation of optical modules are performed in separate steps, and the end face at the intersection of the V-letter shaped optical waveguide, on which the dielectric multilayer filter is formed, is formed by dry etching to achieve high smoothness. Further, a cutting face of the optical module is set at a position that is isolated from the end face at least by 3 &#x3bc;m. Through the above, the smooth end face is protected from roughness of the cutting face caused by a light emitting element separating step, and the dielectric multilayer filter is formed on that end face.

Bidirectional, optical transmitting/receiving module, optical transmitting/receiving device, and bidirectional optical transmitting/receiving module manufacturing method

An edge emitting semiconductor laser suppresses the 'beam steering' to raise its maximum output with a simple configuration. An optical waveguide serving as a resonator includes an active layer and a cladding layer. A first edge, to which one end of the waveguide is connected, serves as an emission edge. A second edge, to which the other end of the waveguide is connected, is located at an opposite side to the first edge. The waveguide includes at least two parts having different widths, one of the at least two parts being a fundamental mode section. Current injection suppressing means is provided for suppressing or controlling current injection into the active layer in at least part of the fundamental mode section. The current injection suppressing means is preferably made by a current blocking layer, a current-limiting masking layer, or a passive wave-guiding region.

Edge emitting semiconductor laser and semiconductor laser module

A semiconductor laser capable of producing a high optical output has a coating film applied to an exit end. The coating film has a refractive index (n,) which is large compared with the refractive index (n,) of a semiconductor waveguide. The refractive index (n,) and the refractive index (n,) satisfy the relationship: n,>n,.

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Tokyo, Japan

Hiroaki Chida