| 摘要 |
PROBLEM TO BE SOLVED: To suppress the optical crosstalk due to two-photon absorption of the output light from a light emitting element of the transmitter-receiver integrated circuit device in its photodetector having an optical guide coupled directly with that of the emitting element. SOLUTION: This device has coupled waveguides of a light emitting element 3 and photodetector 4. The spot size of the output light of the emitting element 3 is set at 8 μm or more in the photodetector 4, thereby reducing the proportion of occurrence of the two-photon absorption of the emitting element 3 in the photodetector. Thus the optical crosstalk is lessened to improve the reception sensitivity of the photodetector 4 and the transmission power is increased to improve the transmission characteristics. Such an optical integrated circuit is used to constitute a low-cost system capable of performing good transmission and reception. |
