| 摘要 |
<p>PURPOSE:To provide a light modulator capable of high speed operation used for optical communication, etc., in which modulator a greater light modulation effect is demonstratable with low drive voltage and a sufficient extinction ratio is achievable. CONSTITUTION:A quantum well structure unit comprises a first quantum well layer W1, a first barrier layer B1 which makes contact with the first quantum well layer W1 and in which electron energy at a point or L is lower than a point GAMMA, and a second quantum well layer W2 which makes contact with the first barrier layer B1 and which possesses its thickness thicker than that of the first quantum well layer W1 or possesses its electron affinity smaller than that of the former but with greater band gap energy then the former. A title light modulator is constructed with a multiple quantum well structure which is yielded by forming in a plurality of periods the foregoing quantum well structure units via a second barrier layer B2 of a thickness enough to prohibit the coupling between adjacent quantum well structure units.</p> |
