Laser diode optical frequency stabilisation technique on ITU-T frequency grid employing modulated sideband light

A novel optical frequency stabilisation technique on the ITU-T frequency grid employing modulated sideband light is proposed. The L-band laser diode second sideband light generated by phase-modulation is locked to a carbon monoxide ¹²C¹⁶O gas absorption line; the original carrier is placed on the ITU-T frequency grid. The square root of Allan variance of 10^-8 has been achieved for a period of 12 h.