A former Asian American employee is suing the Silicon Valley tech company Lumentum, alleging that a yearslong pattern of racism ended with his termination when he tried to speak out. Andre Wong, 52, filed the complaint in the Santa Clara Superior Court on June 30, seeking $20 million in damages. His suit comes amid others by tech workers who say they’re pushing against the “bamboo ceiling,” barriers that have kept Asians from advancing to high-level leadership positions. During his two decades at Lumentum, Wong alleges, he saw management ban Mandarin from being spoken informally at the office, and that he…