Abstract: An optical module includes a driver that generates an electric signal and an optical modulator that has a notch in which at least a portion of the driver is accommodated and performs optical modulation using an electric signal generated by the driver. The optical module also includes a first connector electrically connected to the driver in the notch of the optical modulator. The optical module further includes a second connector provided on a surface of the notch of the optical modulator, the surface being opposed to the first connector. The second connector is electrically connected to the optical modulator. Furthermore, the optical module includes a coaxial pin that is connected to the first connector and the second connector and transmits the electric signal generated by the driver to the optical modulator.

Abstract: An optical module includes a driver that generates an electric signal and an optical modulator that has a notch in which at least a portion of the driver is accommodated and performs optical modulation using an electric signal generated by the driver. The optical module also includes a first connector electrically connected to the driver in the notch of the optical modulator. The optical module further includes a second connector provided on a surface of the notch of the optical modulator, the surface being opposed to the first connector. The second connector is electrically connected to the optical modulator. Furthermore, the optical module includes a coaxial pin that is connected to the first connector and the second connector and transmits the electric signal generated by the driver to the optical modulator.

Abstract: A high-output optical transmitter including a rare earth-doped fiber. The optical transmitter includes a signal light source for outputting signal light having a first predetermined plane of polarization and a pumping light source for outputting pumping light having a second predetermined plane of polarization. The plane of polarization of the signal light from the signal light source is rotated 45 degrees by a Faraday rotator such that the plane of polarization of the signal light output from the Faraday rotator and the pumping light are perpendicular to each other. The signal light from the Faraday rotator and the pumping light from the pumping light source are polarization-coupled by a polarization coupler and the combined light is introduced into the rare earth-doped fiber.

Abstract: An optical fiber amplifier in which light generated within an Er doped optical fiber by spontaneous emission is eliminated or suppressed. By inserting a wavelength demultiplexer in the Er doped optical fiber, the light generated within the optical fiber by spontaneous emission can be effectively eliminated. As an alternative, the Er doped optical fiber is arranged in a coil form with a predetermined radius of curvature to thereby effectively eliminate light due to spontaneous emission on the longer wavelength side than the signal light. Further, by doping the center portion of the core of an optical fiber with aluminum and the whole body of the core uniformly with erbium, it is made possible to suppress the generation of light by spontaneous emission without causing an adverse effect on the amplification performance of the signal light.