diff --git a/libraries/AP_SerialManager/AP_SerialManager.cpp b/libraries/AP_SerialManager/AP_SerialManager.cpp
index a606ecac06..09663e5180 100644
--- a/libraries/AP_SerialManager/AP_SerialManager.cpp
+++ b/libraries/AP_SerialManager/AP_SerialManager.cpp
@@ -66,7 +66,7 @@ const AP_Param::GroupInfo AP_SerialManager::var_info[] = {
     // @Param: 1_PROTOCOL
     // @DisplayName: Telem1 protocol selection
     // @Description: Control what protocol to use on the Telem1 port. Note that the Frsky options require external converter hardware. See the wiki for details.
-    // @Values: -1:None, 1:MAVLink1, 2:MAVLink2, 3:Frsky D, 4:Frsky SPort, 5:GPS, 7:Alexmos Gimbal Serial, 8:SToRM32 Gimbal Serial, 9:Rangefinder, 10:FrSky SPort Passthrough (OpenTX), 11:Lidar360, 13:Beacon, 14:Volz servo out, 15:SBus servo out, 16:ESC Telemetry, 17:Devo Telemetry
+    // @Values: -1:None, 1:MAVLink1, 2:MAVLink2, 3:Frsky D, 4:Frsky SPort, 5:GPS, 7:Alexmos Gimbal Serial, 8:SToRM32 Gimbal Serial, 9:Rangefinder, 10:FrSky SPort Passthrough (OpenTX), 11:Lidar360, 13:Beacon, 14:Volz servo out, 15:SBus servo out, 16:ESC Telemetry, 17:Devo Telemetry, 18:OpticalFlow
     // @User: Standard
     // @RebootRequired: True
     AP_GROUPINFO("1_PROTOCOL",  1, AP_SerialManager, state[1].protocol, SerialProtocol_MAVLink),
@@ -81,7 +81,7 @@ const AP_Param::GroupInfo AP_SerialManager::var_info[] = {
     // @Param: 2_PROTOCOL
     // @DisplayName: Telemetry 2 protocol selection
     // @Description: Control what protocol to use on the Telem2 port. Note that the Frsky options require external converter hardware. See the wiki for details.
-    // @Values: -1:None, 1:MAVLink1, 2:MAVLink2, 3:Frsky D, 4:Frsky SPort, 5:GPS, 7:Alexmos Gimbal Serial, 8:SToRM32 Gimbal Serial, 9:Rangefinder, 10:FrSky SPort Passthrough (OpenTX), 11:Lidar360, 13:Beacon, 14:Volz servo out, 15:SBus servo out, 16:ESC Telemetry, 17:Devo Telemetry
+    // @Values: -1:None, 1:MAVLink1, 2:MAVLink2, 3:Frsky D, 4:Frsky SPort, 5:GPS, 7:Alexmos Gimbal Serial, 8:SToRM32 Gimbal Serial, 9:Rangefinder, 10:FrSky SPort Passthrough (OpenTX), 11:Lidar360, 13:Beacon, 14:Volz servo out, 15:SBus servo out, 16:ESC Telemetry, 17:Devo Telemetry, 18:OpticalFlow
     // @User: Standard
     // @RebootRequired: True
     AP_GROUPINFO("2_PROTOCOL",  3, AP_SerialManager, state[2].protocol, SERIAL2_PROTOCOL_DEFAULT),
@@ -96,7 +96,7 @@ const AP_Param::GroupInfo AP_SerialManager::var_info[] = {
     // @Param: 3_PROTOCOL
     // @DisplayName: Serial 3 (GPS) protocol selection
     // @Description: Control what protocol Serial 3 (GPS) should be used for. Note that the Frsky options require external converter hardware. See the wiki for details.
-    // @Values: -1:None, 1:MAVLink1, 2:MAVLink2, 3:Frsky D, 4:Frsky SPort, 5:GPS, 7:Alexmos Gimbal Serial, 8:SToRM32 Gimbal Serial, 9:Rangefinder, 10:FrSky SPort Passthrough (OpenTX), 11:Lidar360, 13:Beacon, 14:Volz servo out, 15:SBus servo out, 16:ESC Telemetry, 17:Devo Telemetry
+    // @Values: -1:None, 1:MAVLink1, 2:MAVLink2, 3:Frsky D, 4:Frsky SPort, 5:GPS, 7:Alexmos Gimbal Serial, 8:SToRM32 Gimbal Serial, 9:Rangefinder, 10:FrSky SPort Passthrough (OpenTX), 11:Lidar360, 13:Beacon, 14:Volz servo out, 15:SBus servo out, 16:ESC Telemetry, 17:Devo Telemetry, 18:OpticalFlow
     // @User: Standard
     // @RebootRequired: True
     AP_GROUPINFO("3_PROTOCOL",  5, AP_SerialManager, state[3].protocol, SerialProtocol_GPS),
@@ -111,7 +111,7 @@ const AP_Param::GroupInfo AP_SerialManager::var_info[] = {
     // @Param: 4_PROTOCOL
     // @DisplayName: Serial4 protocol selection
     // @Description: Control what protocol Serial4 port should be used for. Note that the Frsky options require external converter hardware. See the wiki for details.
-    // @Values: -1:None, 1:MAVLink1, 2:MAVLink2, 3:Frsky D, 4:Frsky SPort, 5:GPS, 7:Alexmos Gimbal Serial, 8:SToRM32 Gimbal Serial, 9:Rangefinder, 10:FrSky SPort Passthrough (OpenTX), 11:Lidar360, 13:Beacon, 14:Volz servo out, 15:SBus servo out, 16:ESC Telemetry, 17:Devo Telemetry
+    // @Values: -1:None, 1:MAVLink1, 2:MAVLink2, 3:Frsky D, 4:Frsky SPort, 5:GPS, 7:Alexmos Gimbal Serial, 8:SToRM32 Gimbal Serial, 9:Rangefinder, 10:FrSky SPort Passthrough (OpenTX), 11:Lidar360, 13:Beacon, 14:Volz servo out, 15:SBus servo out, 16:ESC Telemetry, 17:Devo Telemetry, 18:OpticalFlow
     // @User: Standard
     // @RebootRequired: True
     AP_GROUPINFO("4_PROTOCOL",  7, AP_SerialManager, state[4].protocol, SerialProtocol_GPS),
@@ -126,7 +126,7 @@ const AP_Param::GroupInfo AP_SerialManager::var_info[] = {
     // @Param: 5_PROTOCOL
     // @DisplayName: Serial5 protocol selection
     // @Description: Control what protocol Serial5 port should be used for. Note that the Frsky options require external converter hardware. See the wiki for details.
-    // @Values: -1:None, 1:MAVLink1, 2:MAVLink2, 3:Frsky D, 4:Frsky SPort, 5:GPS, 7:Alexmos Gimbal Serial, 8:SToRM32 Gimbal Serial, 9:Rangefinder, 10:FrSky SPort Passthrough (OpenTX), 11:Lidar360, 13:Beacon, 14:Volz servo out, 15:SBus servo out, 16:ESC Telemetry, 17:Devo Telemetry
+    // @Values: -1:None, 1:MAVLink1, 2:MAVLink2, 3:Frsky D, 4:Frsky SPort, 5:GPS, 7:Alexmos Gimbal Serial, 8:SToRM32 Gimbal Serial, 9:Rangefinder, 10:FrSky SPort Passthrough (OpenTX), 11:Lidar360, 13:Beacon, 14:Volz servo out, 15:SBus servo out, 16:ESC Telemetry, 17:Devo Telemetry, 18:OpticalFlow
     // @User: Standard
     // @RebootRequired: True
     AP_GROUPINFO("5_PROTOCOL",  9, AP_SerialManager, state[5].protocol, SERIAL5_PROTOCOL),
@@ -143,7 +143,7 @@ const AP_Param::GroupInfo AP_SerialManager::var_info[] = {
     // @Param: 6_PROTOCOL
     // @DisplayName: Serial6 protocol selection
     // @Description: Control what protocol Serial6 port should be used for. Note that the Frsky options require external converter hardware. See the wiki for details.
-    // @Values: -1:None, 1:MAVLink1, 2:MAVLink2, 3:Frsky D, 4:Frsky SPort, 5:GPS, 7:Alexmos Gimbal Serial, 8:SToRM32 Gimbal Serial, 9:Rangefinder, 10:FrSky SPort Passthrough (OpenTX), 11:Lidar360, 13:Beacon, 14:Volz servo out, 15:SBus servo out, 16:ESC Telemetry, 17:Devo Telemetry
+    // @Values: -1:None, 1:MAVLink1, 2:MAVLink2, 3:Frsky D, 4:Frsky SPort, 5:GPS, 7:Alexmos Gimbal Serial, 8:SToRM32 Gimbal Serial, 9:Rangefinder, 10:FrSky SPort Passthrough (OpenTX), 11:Lidar360, 13:Beacon, 14:Volz servo out, 15:SBus servo out, 16:ESC Telemetry, 17:Devo Telemetry, 18:OpticalFlow
     // @User: Standard
     // @RebootRequired: True
     AP_GROUPINFO("6_PROTOCOL",  12, AP_SerialManager, state[6].protocol, SERIAL6_PROTOCOL),
diff --git a/libraries/AP_SerialManager/AP_SerialManager.h b/libraries/AP_SerialManager/AP_SerialManager.h
index 9df1a9fc93..ab0ce12f9a 100644
--- a/libraries/AP_SerialManager/AP_SerialManager.h
+++ b/libraries/AP_SerialManager/AP_SerialManager.h
@@ -101,6 +101,7 @@ public:
         SerialProtocol_Sbus1 = 15,
         SerialProtocol_ESCTelemetry = 16,
         SerialProtocol_Devo_Telem = 17,
+        SerialProtocol_OpticalFlow = 18,
     };
 
     // get singleton instance