| In this work we investigated the structure and performance of vertical cavity surface emitting lasers (VCSEL) which will be used in building an optical quantizer. In any p-i-n structure, capacitance is the most important factor in deciding the highest modulation speed. Therefore, components with smaller capacitance would show higher switching speed. A novel electrical quantizer was constructed using two identical 850 nm Finisar VCSELs, which could manifest electrical switching up to 1.4 MHz. Also, a new electrical quantizer was built with two Eudyna PIN photodiodes (PD-PD), which works at higher frequencies up to 8 MHz, comparing to previous works. The switching photocurrent produced by the PD-PD device was used to modulate a VCSEL. The output of the VCSEL showed the signal with bistable characteristics, however, the amplitude of the optical signal was not large, which was due to the small amplitude of the modulating photocurrent produced by the photodiodes. |
