Glass waveguides made using low melting point nitrate mixtures

Silver-sodium ion exchange is a commonly used method for making waveguides in glass. This paper discusses two exchange media, KNO(3):AgNO(3) and AgNO(3) in NaNO(3):KNO(3) which increase the flexibility of the process and decrease its cost. Exchange in the KNO(3):AgNO(3) can be performed at temperatures as low as 150 degrees C, which is particularly useful for field assisted exchange. When exchange is performed in a NaNO(3):KNO(3) eutectic with small (</=5 mole %) added quantities of AgNO(3), it is possible to control the guide's surface index within the range deltan </= 0.01-0.09 and simultaneously allow the exchange to take place at temperatures as low as 220 degrees C. Because the latter process requires very little of the relatively expensive AgNO(3), it can reduce the cost of the process.