A connector assembly couples signal lines for an optical catheter by providing a guided releasable latching mechanism that ensures optimal alignment with only a single vertical dimension under control. A receptacle carrying a first signal line defines a channel for receiving a plug carrying a second signal line. A spring-loaded pawl on the receptacle locks to a retaining bracket on the plug when the plug slides into the channel, imparting a retaining force on the plug, the force having a first component normal to channel and a second component parallel to the channel to maintain the first and second signal lines in optimal alignment. The retaining bracket may include a sloped edge to allow for easy release of the pawl in the presence of a release force. The release force may be set to allow disconnection of the assembly without affecting catheter installation or causing patient discomfort.