Variation in waveguides fabricated by immersion of LiNbO3in AgNO3and TlNO3: The role of hydrogen

摘要

Optical waveguides fabricated in LiNbO3by what has previously been described as silverhyphen;lithium or thalliumhyphen;lithium ion exchange in the molten nitrates AgNO3or TlNO3have not generally been reproducible. We show that the large increases of the extraordinary index (Dgr;ne= 0.12), which are observed intermittently, result not from introduction of the heavy ions, Ag+or Tl+, but from hydrogenhyphen;lithium exchange, which occurs when hydrogen is present as an impurity in the melts.