| 摘要 |
<p>A tunable laser system (10) comprises an external-cavity laser diode (15) in combination with an optically coupled waveguide (20) having a Bragg grating (25) formed therein. The laser diode (15) provides a gain medium characterized by a first band of wavelengths. A portion of the fiber (20) and the grating (25) help define an external resonant cavity. The grating (25) limits the wavelengths exciting the external cavity to a second band that is typically much narrower than the first band. The grating region of the waveguide is thermally coupled to a heating element (30) having an associated temperature controller (32) for controllably varying the temperature of the grating (25) region and thus changing the optical pitch of the grating (25) and thus the second band. The grating region of the waveguide (20) can alternatively, or additionally, be subjected to acoustic energy (45) to change the optical pitch of the grating (25).</p> |
