MEMS Tunable nanostructured photodetector

This thesis was prepared at the department of Photonics Engineering, the Technical University of Denmark in fulfilment of the requirements for acquiring a Philosophiae doctor (Ph.D.) in Photonics Engineering. The thesis deals with the design and fabrication of tunable resonant-cavity-enhanced photodetector using dielectric subwavelength gratings as reflectors operating at 1550 nm optical communication wavelength. The main work in this thesis divided equally into device design and process development. The properties of dielectric subwavelength grating are described. The main result of the thesis is the new resonant cavity structure using dielectric subwavelength gratings as ultra high reflective broadband reflectors and process development to realize the design. The tuning characteristics are reported for different types of cavities and compared with the conventional distributed Bragg reflector (DBR) structure. Results from the fabricated devices are reported along with an investigation of the design parameters which influence the performance deviation from the design.