Broadband optical coupling modulation

A KD*P internal coupling modulator has been operated in a high-power single-frequency 0.63-micron He-Ne laser similar to that described earlier by Smith. It is shown that distortion in the output due to resonant buildup of energy in the passive cavity modes when the modulation frequency is equal to
c/2L
can be reduced to an acceptable level. The modulator bandwidth was greater than 700 MHz, and the maximum optical output power was 3.6 mW. For an optical output power of 0.5 mW, the performance index was estimated to be 0.4 mW of RF driving power for each MHz of bandwidth.