Closed-form expressions for propagation characteristics of diffused planar optical waveguides

✍ Scribed by Ashmeet Kaur Taneja; Sangeeta Srivastava; Enakshi Khular Sharma

• Publisher: John Wiley and Sons
• Year: 1997
• Tongue: English
• Weight: 195 KB
• Volume: 15
• Category: Article
• ISSN: 0895-2477
• DOI: 10.1002/(sici)1098-2760(19970805)15:5<305::aid-mop11>3.0.co;2-4

✦ Synopsis

sion line by almost 2 ⍀ and 0.5᎐0.75 cmrns, respectively. Because the SiO layer has a significantly lower dielectric 2 constant than that of GaAs, its inclusion will result in a smaller capacitance per unit length of the CPS slow-wave electrodes. This results in an increase in the phase velocity of the microwave signal and the characteristic impedance of the line. Table 1 shows the calculated phase velocities and characteristic impedances obtained from the s parameter at 20 GHz for all processing conditions. At 40 GHz, the measured losses were found to be about 5 dBrcm for all of the four conditions under study.

The simulated values for phase velocity and characteristic Ž . impedance of the CPS shown in Figure 1 for case b are 8.87 cmrns and 51.1 ⍀ at 20 GHz, respectively. The measured values for this case are 8.25 cmrns and 46.7 ⍀, at the same frequency. This difference is believed to be due to the fact that the physical dimensions of the loading fins and pads, such as L , W , and G, are very critical. If some of these p s