Microwave signal generation with discrete mode laser diode

Abstract

Microwave signals with low phase noise can be broadly used in communication systems, satellite communications, and radar systems. Discrete mode laser diode (DM-LD) has the capacity to generate signals that meet the above requirements. Moreover, it has the following advantages such as stable operation over a wide temperature range, very high side mode suppression ratio, low sensitivity to optical feedback, and narrow linewidth. In this paper, we proposed and experimentally demonstrated DM-LD for generating the second harmonic signal in the self-starting microwave generation system. The results show that DM-LD effectively reduces the single sideband (SSB) phase noise of the fundamental signals and its second harmonic signals better than the same designed experimental system using a distributed feedback LD, which reduces the SSB noise of the fundamental signal/its second harmonic signal by over 16/22 dB, 18/22 dB, 13/19 dB at a frequency offset of 10 kHz, 100 kHz, and 1 MHz, respectively.

Semiconductor laser and polarization modulator for W-band signal generation

“…In a previous study [18], the self-started system, such as the phase modulator, requires a large signal gain with high modulation depth to suppress the sideband carriers, which requires the involvement of more than one signal amplifier. However, the SSB phase noise increases with the presence of a signal amplifier [19], and there is also the possibility that the SSB phase noise increases nonlinearly through the serial connection of the signal amplifiers [20].…”