| 摘要 |
PURPOSE:To enable non-contact and exact detection of the temp. fluctuation in optical filters as light information by forming the two optical filters on the same substrate by using two kinds of materials having the different temp. coeffts. of refractive index. CONSTITUTION:The optical filters F1, F2 are formed by using the ring interferometers of the same shape and waveguides 5, 8, 9 (or 6, 10) are formed by using InP (or GaAs), on the substrate 7. A directional coupler 1 couples input light Pi to the filters F1, F2 and a coupler 2 bisects the output light P01 from the filter F1. Couplers 3, 4 branch the light advancing in linear waveguides 9, 10 to ring type waveguides 5, 6. The input light Pi; for example, 1.55mum light, is split to 2:1 by the coupler 1 and is branched to the filters F1, F2; further, the output light P01 is bisected by the coupler 2, when said light is inputted to this element. The respective temp. coeffts. of the refractive index of InP and GaAs move by 84MHz and 127MHz to the low-frequency side if it is assumed that the temp. of the element rises by 0.01 deg.C. The temp. fluctuation quantity is, therefore, obtd. by detecting the same. |
