Opnext Japan Inc. | Date: 2012-02-23
A differential transmission circuit includes a pair of transmission line conductors and a ground conductor layer, wherein the pair of transmission line conductors include a first straight line region where both the pair of transmission line conductors extend in parallel to each other in a first direction with a first width in a first layer, a first cross region where one of the pair of transmission line conductors is formed in the first layer, the other thereof is formed in a second layer, and the pair of transmission line conductors cross the each other in a three-dimensional manner, the first cross region being disposed on the front side of the first straight line region, and wherein each of the widths of the pair of transmission line conductors in the first cross region is smaller than the first width.
Opnext Japan Inc. | Date: 2012-05-14
The I phase modulator modulates a phase based on the bias voltage in which a first modulation signal and a first pilot signal are inherent and the Q phase modulator modulates a phase based on the bias voltage in which a second pilot signal different from the first pilot signal and a second modulation signal are inherent. A time-average power synchronous detection unit detects an optical power at a timing at which the positivity and negativity of the voltages of both pilot signals become the same, and an optical power when the positivity and negativity of the voltages of both pilot signals are opposite. The bias voltage control unit controls the bias voltage so that the difference between both the optical powers becomes small based on the detection result of the time-average power synchronous detection unit.
Opnext Japan Inc. | Date: 2012-06-05
An optical device includes a ridge-like optical waveguide portion, a mesa protector portion that is arranged in parallel to the optical waveguide portion, a resin portion that covers upper parts of the mesa protector portion and is disposed at both sides of the mesa protector portion, an electrode that is disposed on the optical waveguide portion, an electrode pad that is disposed on the resin portion located at an opposite side to the optical waveguide portion with respect to the mesa protector portion, and a connection portion that is disposed on the resin portion and electrically connects the electrode to the electrode pad.
Opnext Japan Inc. | Date: 2012-05-07
A light-receiving device array includes a photodiode array that is provided with plural light-receiving sections each of which includes a first conductivity type electrode and a second conductivity type electrode, and a carrier, wherein the carrier includes plural pair of electric lines each of which is formed from a first electric line connected to the first conductivity type electrode of each light-receiving section, and a second electric line connected to the second conductivity type electrode of the light-receiving section, a first ground electrode that extends between one pair of electric lines of the plural pair of electric lines and a pair of electric lines adjacent to the one pair of electric lines, and a second ground electrode that is formed on a part of the rear surface and is electrically connected to the first ground electrode.
Opnext Japan Inc. | Date: 2012-05-11
A wavelength tunable filter and a wavelength tunable laser module are a codirectional coupler type whose characteristics do not vary significantly with a process error. They are structured so as to include a semiconductor substrate which has a first optical waveguide and a second optical waveguide. The first and the second optical waveguides are extended from a first side of the semiconductor substrate to an opposing second side thereof. The first optical waveguide includes a first core layer, which has a planar layout having periodic convexes and concaves, and a pair of electrodes, which vertically sandwich the first core layer. The second optical waveguide includes a second core layer, which has a lower refractive index than the first core layer. Further, a layer having the same composition and film thickness as the second core layer is placed under the first core layer.