An Overview : Optical Frequency References
C2H2
C2HD
Rb
Ca
I2
CH4
H
3390
1556
1064
778
657
532
486
Well studied optical frequency references
v1+v3  combination band of acetylene
Robust and stable frequency
communication and navigation System
      - Frequency division multiplexing
    - Spectrum analyzer
Sarah L. Gilbert, W.C.S., Acetylene 12C2H2 Absorption Reference for 1510 nm to 1540 nm Wavelength
 Calibration-SRM 2517a. 2001