Title :
An absolute frequency reference at 192.6 THz (1556 nm) based on a two-photon absorption line of rubidium at 778 nm for WDM communication systems
Author :
Poulin, M. ; Latrasse, C. ; Cyr, N. ; Tetu, M.
Author_Institution :
Dept. de Genie Electr. et de Genie Inf., Laval Univ., Que., Canada
Abstract :
A 192.6-THz (1556 nm) distributed-feedback (DFB) laser is frequency-locked on a two-photon transition of rubidium at 385.3 THz (778 nm) using second-harmonic (SH) generation. With 43 mW at 1556 nm, we obtain a SH power of 15 μW using a KNbO3 crystal placed in a ring cavity. Optical feedback from this cavity is used to reduce the DFB laser linewidth to the 10-kHz level and control its frequency. The SH signal is used to injection-lock a 778-nm Fabry-Perot laser in order to increase the interrogation power. With this scheme, we observe two-photon transitions in rubidium and lock the 1556-nm laser frequency.
Keywords :
distributed feedback lasers; laser feedback; laser frequency stability; laser transitions; measurement standards; optical communication equipment; optical harmonic generation; rubidium; semiconductor lasers; spectral line breadth; two-photon processes; wavelength division multiplexing; 15 muW; 1556 nm; 43 mW; 778 nm; DFB laser; DFB laser linewidth reduction; Fabry-Perot laser; KNbO/sub 3/; KNbO/sub 3/ crystal; Rb; SH power; WDM communication systems; absolute frequency reference; distributed-feedback laser; frequency standards; frequency-locked; injection-lock; interrogation power; laser frequency locking; optical feedback; ring cavity; rubidium; second-harmonic generation; two-photon absorption line; two-photon transition; two-photon transitions; Distributed feedback devices; Distributed power generation; Fabry-Perot; Frequency; Laser feedback; Laser transitions; Optical control; Optical feedback; Power lasers; Ring lasers;
Journal_Title :
Photonics Technology Letters, IEEE
