Device for Monitoring
Provided is a device for monitoring that realizes monitoring of an influence of thermal stress on a phase of an optical circuit on a surface where an optical circuit is formed. The device for monitoring according to the present disclosure is a device for monitoring for monitoring an influence of thermal stress on a phase of an optical circuit during mounting or actual operation on an optical module manufactured by a bare chip mounting method, wherein the device for monitoring includes a substrate and a plurality of stress sensitive circuits formed on the substrate, and wherein the device for monitoring is arranged on a surface of the optical module on which the optical circuit is formed, and monitors the influence of thermal stress on a phase of the optical circuit on the basis of either signal light propagating through the optical circuit or external light input from the outside.
1 . A device for monitoring for monitoring an influence of thermal stress on a phase of an optical circuit during mounting or actual operation on an optical module manufactured by a bare chip mounting method, wherein the device for monitoring comprises:
a substrate; and
a plurality of stress sensitive circuits formed on the substrate, and wherein
the device for monitoring is arranged on a surface of the optical module that the optical circuit is formed, and monitors the influence of thermal stress on a phase of the optical circuit on the basis of either signal light propagating through the optical circuit or external light input from the outside.
2 . The device for monitoring according to claim 1 , wherein the stress sensitive circuits each also include an optical interferometer, and the device for monitoring monitors the influence of the thermal stress on the phase of the optical circuit on the basis of a change in light transmission spectrum output by the optical interferometer.
3 . The device for monitoring according to claim 1 , wherein the stress sensitive circuits each also include a Ge photodiode, and the device for monitoring monitors the influence of the thermal stress on the phase of the optical circuit on the basis of a change in absorption spectrum of Ge output by the Ge photodiode.
4 . The device for monitoring according to claim 1 , wherein the stress sensitive circuits each also include:
an optical input port that the signal light or the external light is input;
a phase adjustment optical circuit that adjusts a phase of the signal light or the external light input from the optical input port; and
a detector that detects power of the signal light or the external light output from the phase adjustment optical circuit, and wherein
the device for monitoring monitors the influence of the thermal stress on the phase of the optical circuit on the basis of an amount of phase adjustment in the phase adjustment optical circuit obtained when the power of the signal light or the external light detected by the detector becomes maximum.
5 . The device for monitoring according to claim 4 , wherein a light source of the external light is integrated on the substrate.
6 . The device for monitoring according to claim 4 , wherein the stress sensitive circuits are connected in series in a plane that the optical circuit is formed.
7 . The device for monitoring according to claim 4 , wherein resonance wavelengths of the respective stress sensitive circuits are set in advance so as to vary.