High-Q SAW filter and submicron process technology for timing extraction in high bit rate optical communications system

A new surface acoustic wave (SAW) filter configuration that consists of 3/spl lambda//8-wide meander-type electrodes and 3/spl lambda//8-wide excitation electrodes on ST-cut quartz was designed for use in a 2.5-Gb/s optical communications system. New submicron process techniques using the phase shifting method as well as several types of resist were investigated to fabricate this filter. It had an insertion loss of less than 14 dB and a Q of about 700, and satisfied all required system specifications over a temperature range from 0 to 60/spl deg/C.