Intracavity Biosensor Based On V-coupled Cavity Laser

With The Internet of Things proposed and developed, "Instrument the world's systems; Interconnect them; Make them intelligent" becomes the main direction of internet of things. Bio-sensing technology as an interdisciplinary high-tech "aware" technology, widely used in clinical medicine, biological sciences, military science, drug analysis, environmental monitoring and many other disciplines. Research and development momentum continues to increase in the field of bio-sensing, and is also accelerating the pace of commercialization. As a direct detection method, as well as its non-destructive mode of operation, fast rate of signal generation and reading, optical biosensors has received great interest. In recent years, with the rapid development of integrated optoelectronic devices, the optical bio-sensing becomes another important application area after optical fiber communication.In the thesis we propose a novel integrated optical intracavity laser biosensor, which includes a V-coupled cavity laser and a 2×2 multimode interference coupler. The optical cavity length of one of the resonator is about twice of the other. As a result, when the lasing mode of the fixed cavity shifts from one mode to the next because of the effective refractive index variation in the sensing cavity caused by the sample index variation, the phase difference between the input port of the MMI coupler will experience aπphase change. By simply detecting the power ratio of two output ports, a refractive index sensitivity in the order of 10"8 RIU can be achieved.To investigate the biosensor in detail, we used Rsoft to design the structure of the device, including the waveguide design, and the coupling of active and passive waveguide. By using laser threshold condition and multi-mode rate equation, the sensitivity of the sensor were analyzed. Compared with the other integrated optical biosensors, the main innovations of this thesis include, the integration of the active semiconductor laser source and photodetector with passive sensor; the double Vernier effect with MMI coupler to realize intensity interrogation without the need for any spectral measurement; the intracavity mechanism and a Vernier amplification effect to greatly increase the sensitivity.