| 摘要 |
PROBLEM TO BE SOLVED: To solve the problem of a conventional semiconductor optical modulator that electrode wiring tends to expand and become more complicated as the elements are developed to deal with higher speed and capacity, where the complication of electrode structures has been unavoidable even with a capacitive loading type structure that allows use of a single electrode; and the problem of optical absorption and non-linear response characteristics in optical modulation operation, where non-linear response of refractive index to drive voltage associated with the FK effect and QCSE, and light intensity imbalance between arm waveguides caused by the Kramers-Kronig relations cause degradation in the linear responsiveness and optical signal quality.SOLUTION: A semiconductor optical modulation element of the present invention includes an MZ optical modulation waveguide, having a semi-insulating core layer in a predetermined direction, formed on a (110) plane substrate. Each side face of a waveguide mesa is embedded with an n-type cladding layer and an n-type contact layer. A single electrode comprising G-S-G wiring of a simple structure is formed in the middle between MZ waveguide arms. Push-pull modulation by a coplanar MZ optical modulator is driven by changing a refraction index by means of the Pockels effect which does not accompany light absorption. |
