这个可以有。
这里as 是连词。这是带连词的过去分词短语作状语,相当于一个状语从句,等于As it is known to all.
而as is known to all是非限制性定语从句。此时as是关系代词代替后面句子所表达的内容。
二者意思一样,但句子结构不一样。
再如
As known to all, jurisdiction is the last way to guard social justice.
众所周知,司法是捍卫社会正义的最后一道防线。
它和 as is known to all 是相同的意思,都是“众所周知”,而用法上面略有些不同,as is known to all 只可以用在句首或句尾,用“,”隔开.而as it is known to all不仅可以放在句首,还可以后面加“that”从句.而it is known to all 是形式主语的典型,只用于如it is known to all that our teacher is beauful.
不可以省略。