title: Optical phase locking with a large and tunable frequency difference based on a vertical-cavity surface-emitting laser.
abstract: We present a novel method to phase lock two lasers with a controllable frequency difference. A microwave frequency-modulated vertical-cavity surface-emitting laser is used to phase connect two diode lasers by a two-step injection locking. The phase fluctuations of the two lasers are measured to be 6.4 x 10(-4) rad2, corresponding to 99.94% phase coherence. The frequency difference of the two lasers is tunable up to tens of gigahertz. The sideband suppression of the slave laser is more than 30 dB at 30 microW seed power. A narrow linewidth spectrum of coherent population trapping in rubidium is achieved using such beams.
authors.affiliation: Institute of Quantum Electronics, School of Electronics Engineering and Computer Science, Peking University, Beijing 100871, China.
authors.forename: Wenlan
authors.initials: W
authors.lastname: Chen
authors.forename: Xianghui
authors.initials: X
authors.lastname: Qi
authors.forename: Lin
authors.initials: L
authors.lastname: Yi
authors.forename: Ke
authors.initials: K
authors.lastname: Deng
authors.forename: Zhong
authors.initials: Z
authors.lastname: Wang
authors.forename: Jingbiao
authors.initials: J
authors.lastname: Chen
authors.forename: Xuzong
authors.initials: X
authors.lastname: Chen