Wavelength tuning mechanism in three-electrode DFB lasers

The wavelength tuning mechanism is investigated for three-electrode distributed feedback (DFB) InGaAs-InGaAsP lasers. It is shown that the side and center sections play different roles in wavelength tuning: the former determines the effective Bragg wavelength and the latter contributes through the round-trip phase condition. The lasing wavelength is expressed in a simple form that renders the wavelength shift behavior exceedingly understandable. The indispensability of the thermal contribution to continuous broad range tuning is also clarified both theoretically and experimentally.<
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