Frequency stabilization of 1.55 mu m DFB laser diode using vibrational-rotational absorption of /sup 13/C/sub 2/H/sub 2/ molecules

The vibrational-rotational absorption of /sup 13/C/sub 2/H/sub 2/ molecules (VRAMs) in the 1.52-1.55 mu m region was investigated in detail. On the basis of this investigation, frequency stabilization of 1.55- mu m distributed-feedback (DFB) laser diodes was demonstrated. Frequency stability to within 2 MHz peak/peak fluctuation was achieved at the 1.54949- mu m wavelength. In addition, frequency stabilizations in the wavelength regions of 1.53 mu m and 1.54 mu m were also carried out by using the strong absorption lines of /sup 13/C/sub 2/H/sub 2/ VRAM in these wavelength regions. The spectral width of the frequency-stabilized DFB laser diode was found to be 25 MHz. The absolute frequency was found to be stabilized at least to within 25 MHz by the measurement of beat spectrum.<
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