Abstract: WDMs have been used to separate a plurality of signals spatially by the difference of wavelengths in prior bidirectional multiwavelength optical communication network. For excluding WDMs, linear PD/LD modules adopt eigen-wavelength photodiodes sensing only the light of an eigen wavelength but allowing all the wavelengths longer than the eigen wavelength. An n-member PD/LD module aligns (n-1) eigen wavelength photodiodes, PD1, PD2, PD3, . . . , PDn-1 of .lambda.1, .lambda.2, .lambda.3, . . . ,.lambda.n-1 and an LD of .lambda. n which satisfy inequalities .lambda.1<.lambda.2<.lambda.3 <. . . <.lambda. n in series on a beam line in the order of increasing the eigen wavelengths. Otherwise, an n-member PD/LED module aligns k eigen wavelength PDs of .lambda.1, .lambda.2, .lambda.3, . . . , .lambda.k and (n-k) LEDs emitting light of different wavelengths of .lambda.k+1, .lambda.k+2, .lambda.k+3, . . . .lambda. n on the beam line in the same order. On the contrary, an n-member LD/PD module aligns a .

Abstract: In a light emitting element module of the present invention, a lens as an optical system for coupling an optical fiber with light emitted from a light emitting element mounted on a substrate is provided for the light emitting element, and the distance between the light emitting element and the lens is defined by a spacer inserted between the substrate and a holder for the lens mounted on the substrate. When this light emitting element module is manufactured, the distance between the light emitting element and the lens is desirably adjusted by properly selecting the thickness of the spacer to be used at that time.

Abstract: A card-shaped optical data link device is utilized for transmitting and receiving data in optical communications using an existing card slot of a computer, electronic devices etc. The card-shaped optical data link device of the present invention comprises an electric connector, electric signal processor electrically connected to the electric connector, an optical transmission module, an optical reception module electrically connected to the electric signal processor, an optical connector for supporting the optical transmission module and the optical reception module, a frame for supporting the electric connector and the optical connector at a position opposing to the electric connector, and a pair of panels for sandwiching the frame and constituting an envelope with the frame. The electric connector, the electric signal processor, the optical transmission module, the optical reception module and the optical connector are located within the envelope.

Abstract: A semiconductor laser device in which a housing with an optical fiber inserted in is secured to a header with a semiconductor laser chip mounted on is integrated, the light emitting surface of the semiconductor laser chip and the end surface of the optical fiber are opposed to each other, and there is provided a photodiode chip for detecting the signal light emitted from the backside (rear end surface) of the light emitting surface of the semiconductor laser chip, in the top incidence type photodiode chip having a pn junction area of the structure as a photo-sensing region, the first region is surrounded by a second region of the second conductivity type formed at a portion of the semiconductor layer. The second region has the same or larger depth as or than that of the first region. Thus, even if a light is directed to the outside of the photo-sensing region, extra charges into the photo-sensing region is prevented.

Abstract: A semiconductor laser module is used for transmitting signals by optical fiber in optoelectronic communication. The module comprises a semiconductor laser, a lens, a receptacle and a lens holder. Reflection beams at an end of a fiber must not return to the semiconductor laser. To deviate the reflection beams from the semiconductor, a key-shaped glass block is mounted in the receptacle in tight contact with the end of a fiber. Repetition of putting on and taking off ferrules contaminates the glass block. Adhesion of dust deteriorates the performance against noise induced in the laser by the return of the beam. To avoid the adhesion of dust to the surface of the transparent block, a key-shaped transparent block is inserted into an axial hole of the receptacle, separating from the block. A gap between the block and fiber prohibits dust from cohering to the block. The deviation of axes of the receptacle and lens holder is small enough. The assembly is easy.

Abstract: A disc player for playing compact audio discs includes a plurality of horizontally spaced disc compartments each including a disc tray for holding a disc horizontally and a disc playback module horizontally movable between and alignable with the disc compartments for playing the discs held in the disc trays. Each disc tray is independently extendable from or retractable into its respective disc compartment for loading and unloading discs in the disc compartment.