| 摘要 |
<p>PROBLEM TO BE SOLVED: To introduce a quantum well absorbing layer into a saturable Bragg reflector used in a mode-locked laser, by locating a quantum well within high refractive index layers having an optical thickness equal to a predetermined value of an operating wavelength, and sandwiching each high refractive index layer between low refractive index layers having a predetermined value of the operating wavelength. SOLUTION: The saturable Bragg reflector 20 has a single crystal GaAs substrate, with low refractive index layers 22 and high refractive index layers 24 epitaxially grown thereon alternately. Each layer 22 has an optical thickness equal to 1/4 of an operating wavelength, and each layer 24 excluding the two uppermost ones 26A and 26B has an optical thickness equal to 1/4 of the operating wavelength. The layers 26A and 26B have an optical thickness equal to 1/8 of the operating wavelength. Further, a quantum well 28 is a layer having a thickness of about 100Åmade of a low refractive index material, and is located near the center of the GaAs layers 26A and 26B.</p> |
