Abstract

It is now well established that the output from a diode laser or light emitting diode driven by a constant current source can be far below the standard quantum limit (SQL)[1], However, except for measurements that close-couple the laser and detector, the observed amplitude squeezing has been limited to 1.5 dB. Recently, it has also been suggested that the amplitude- squeezed light can be converted into a squeezed vacuum by phase-locking the laser to a coherent injection signal[2]. In this paper we report production of amplitude squeezed light by injection locking. 3 dB amplitude squeezing has been observed with injection-locked diode lasers (Spectra Diode Labs SDL-5410-C). Our measurements also show that injection-locking can significantly improve the level of squeezing by suppressing weak side modes that feature amplitude noise far above the SQL.

© 1993 Optical Society of America