Yes you can apply.. you need to Give TOEFL/GRE... TWE/TSE is also recommened to be taken..

http://www.gradoffice.caltech.edu/documents/Appinstructions.pdf 

Admission is highly competitive, and applicants are evaluated on the basis of a number of criteria including transcripts, letters of recommendation from former teachers, standardized test scores (including, when appropriate, TOEFL scores), written statements of purpose, appropriateness of research interests, and research experience and promise