WAVELENGTH TUNING MECHANISM IN 3-ELECTRODE DFB LASERS

The wavelength tuning mechanism is investigated for three-electrode DF B lasers. The side and center sections play different roles in wavelen gth tuning; specifically, the former determines the effective Bragg wa velength, while the latter contributes through the round-trip phase co ndition. The lasing wavelength is expressed in a simple form that rend ers the wavelength shift behavior exceedingly understandable. The indi spensability of the thermal contribution to continuous broad range tun ing is also clarified both theoretically and experimentally.