Microwave modulation characteristics of a dual-frequency laser diode

Abnormal modulation characteristics of a DBR-type dual-frequency laser diode will be reported. Applying strong but relatively low frequency (less than 3.5GHz) microwaves on a dual-frequency LD, average output power of the short-wavelength oscillation of the LD was enhanced, and the long-wavelength oscillation line was suppressed. With increasing microwave injection frequency up to 4GHz, the situation was reversed; namely the short-wavelength oscillation was suppressed and the long-wavelength oscillation was enhanced. Much higher frequency (over 4.5GHz), the situation was reverted to the low-frequency area.