WAVEGUIDE TYPE OPTICAL INTERFEROMETER CIRCUIT

摘要

PURPOSE:To obtain a circuit which has a superior quenching ratio and small excessive loss by using a directional coupler of what is called (3X3) constitution which have coupling optical waveguides arranged nearby both ends of input/ output optical waveguides as an optical coupler. CONSTITUTION:The coupling optical waveguides 2a and 2b are arranged closely about an input/output optical waveguide 3a to specific length (l). The coupling waveguides 2a and 2b in the optical coupling part 22 of length (l) are arranged symmetrically about the center axis 23 of the optical waveguide 3a. When signal light which is guided in the optical waveguide 3a reaches the optical coupling part 22, evanescent coupling from the center optical waveguide to both-side optical waveguides is generated and when the length (l) is set properly (complete coupling length), the signal light of the center optical waveguide all travels to both-side optical waveguides before reaching the exit of the optical coupling part 22, thereby performing desired optical coupler operation. Consequently, the waveguide type optical interferometer circuit whose loss characteristics and quenching characteristics are both excellent is obtained.