Undesired mode suppression of optical millimeter wave signal generated by injection-locked Fabry-Perot laser diode

Abstract

We investigate the undesired locked-mode suppression in the sub-harmonically injection locking of the Fabry-Perot laser to generate the two-mode optical millimeter-wave signal. We achieve that more than 13dB improvement of the UDLM suppression can be achieved by optimizing the injection power and the modulation index of the master laser.

Single-Frequency Tunable Fiber Ring Laser Based on Erbium-Doped Waveguide Amplifier and Double Filters

“…Furthermore, to suppress undesired modes and stabilize the frequency, the injection locking technique is applied to the FP-LD. 8,9) As a result, a 1.11 nm tuning step is determined by the longitudinal-mode spacing of the injection-locked FP-LD. The output power spectrum is observed using an optical spectrum analyzer (OSA) and single-frequency operation is verified using a photodetector with a 3 dB bandwidth of 12 GHz and a radio-frequency (RF) spectrum analyzer.…”

“…If injected light with wavelength , which is determined by the FFP filter, is added and aligned with one longitudinal mode of the FP-LD, the locked mode grows and all the side modes could be considerably suppressed. 9) As a result, the spectral output of the injection-locked FP-LD has only one longitudinal mode at . Figure 3 indicates the output power and SMSR versus the lasing wavelength varied in 1.11 nm tuning steps.…”