An optical bus system having a start-up state and an operating state, said system comprising: a mechanical support structure; a master module mechanically attached to said mechanical support structure, said master module comprising a downstream optical communication interface comprising a master optical transmitter and a master optical receiver; a set of slave modules mechanically attached to said mechanical support structure sequentially in a row next to said master module, the set of slave modules including a first slave module arranged next to said master module and at least one subsequent slave module, each slave module including: processing circuitry, an upstream optical communication interface comprising an upstream optical receiver and an upstream optical transmitter, a downstream optical communication interface comprising a downstream optical receiver and a downstream optical transmitter, a downstream signal path from said upstream optical receiver to said downstream optical transmitter via said processing circuitry, and an upstream signal path from said downstream optical receiver to said upstream optical transmitter via said processing circuitry; wherein the upstream optical communication interface of the first slave module is in optical contact with the downstream optical communication interface of the master module, and the upstream optical communication interface of each subsequent slave module is in optical contact with a downstream optical communication interface of a preceding slave module in the row, in order to enable optical communication between adjacent modules; wherein, during said start-up state, in each slave module, said processing circuitry is configured to implement a daisy-chain topology and to perform an addressing procedure whereby said master module is configured to retrieve a position and an identity code of each slave module; characterized in that, during said operating state, in each slave module, said processing circuitry is configured to close an upstream switch such that a shunting upstream signal path is formed from said downstream optical receiver to said upstream optical transmitter, in addition to said upstream signal path, the shunting upstream signal paths of the set of slave modules together forming an upstream optical bus allowing each slave module to communicate directly with said master module using said positions and identity codes. a mechanical support structure; a master module mechanically attached to said mechanical support structure, said master module comprising a downstream optical communication interface comprising a master optical transmitter and a master optical receiver; a set of slave modules mechanically attached to said mechanical support structure sequentially in a row next to said master module, the set of slave modules including a first slave module arranged next to said master module and at least one subsequent slave module, each slave module including: processing circuitry, an upstream optical communication interface comprising an upstream optical receiver and an upstream optical transmitter, a downstream optical communication interface comprising a downstream optical receiver and a downstream optical transmitter, a downstream signal path from said upstream optical receiver to said downstream optical transmitter via said processing circuitry, and an upstream signal path from said downstream optical receiver to said upstream optical transmitter via said processing circuitry; processing circuitry, an upstream optical communication interface comprising an upstream optical receiver and an upstream optical transmitter, a downstream optical communication interface comprising a downstream optical receiver and a downstream optical transmitter, a downstream signal path from said upstream optical receiver to said downstream optical transmitter via said processing circuitry, and an upstream signal path from said downstream optical receiver to said upstream optical transmitter via said processing circuitry; wherein the upstream optical communication interface of the first slave module is in optical contact with the downstream optical communication interface of the master module, and the upstream optical communication interface of each subsequent slave module is in optical contact with a downstream optical communication interface of a preceding slave module in the row, in order to enable optical communication between adjacent modules; wherein, during said start-up state, in each slave module, said processing circuitry is configured to implement a daisy-chain topology and to perform an addressing procedure whereby said master module is configured to retrieve a position and an identity code of each slave module; characterized in that, during said operating state, in each slave module, said processing circuitry is configured to close an upstream switch such that a shunting upstream signal path is formed from said downstream optical receiver to said upstream optical transmitter, in addition to said upstream signal path, the shunting upstream signal paths of the set of slave modules together forming an upstream optical bus allowing each slave module to communicate directly with said master module using said positions and identity codes.