Optical add-drop multiplexer (oadm) market was valued at USD 1,116 million in 2026 and is projected to reach USD 3,057 million by 2036, recording a CAGR of 10.6% during 2027–2036. Asia-Pacific was the largest region in 2026 at an estimated ~38% share. The market centers on passive fixed wavelength filters and photonic wavelength-selective switch modules integrated into ROADM nodes for DWDM channel add, drop and express switching.