Microwaving Avocados does not actually ripen the Avocados but only makes it seem like the Avocado is ripened.
What actually happens when you Microwave the Avocado is the flesh softens which makes it seem like the Avocado has ripened.
But there's no way to actually ripen an Avocado faster such as in the oven or microwave.
You can however put a cut Avocado into the refrigerator after wrapping the Avocado in some cling wrap and let it sit in the refrigerator for a few hours to a all day depending on how unripe the Avocado is.
I've tried the microwaving the Avocados to ripen them before as well as putting them in the oven and it doesn't really work but only makes it seem like the Avocados are ripe which they are not.