An optical arrangement for a light detecting system, the optical arrangement being configured: - to steer an illumination beam along an illumination optical path from a laser source to a target to be sensed, in a transmitting direction, and - to transmit a reflected beam along a return optical path from the target to an optical detector, in a receiving direction, wherein the reflected beam comprises a reflection of the illumination beam on the target, the optical arrangement comprising: - a transceiver arrangement comprising a dichroic beamsplitter, the transceiver arrangement being configured for: * transmitting a source beam from the laser source to a first end of an optical fiber arrangement, in one way selected among: through or by reflection on the dichroic beamsplitter, and * transmitting the reflected beam from said first end of the optical fiber arrangement to the optical detector in the other way selected among: through or by reflection on the dichroic beamsplitter, - the optical fiber arrangement comprising a multi-clad optical fiber which comprises a core, at least one inner cladding, and an outer cladding; wherein said core is arranged to receive the source beam having a first wavelength, such that the source beam propagates in the core in said transmitting direction, and the core is further configured to generate a scanning beam from the source beam propagating in the core, wherein the scanning beam comprises at least a second wavelength which is different from the first wavelength, and said at least one inner cladding is configured to receive the reflected beam, comprising the at least second wavelength, such that the reflected beam propagates in the inner cladding in said receiving direction, - a scanning unit optically coupled to a second end of the optical fiber arrangement, the scanning unit being configured to steer the scanning beam to said target, and to receive the reflected beam from the target. - to steer an illumination beam along an illumination optical path from a laser source to a target to be sensed, in a transmitting direction, and - to transmit a reflected beam along a return optical path from the target to an optical detector, in a receiving direction, wherein the reflected beam comprises a reflection of the illumination beam on the target, - a transceiver arrangement comprising a dichroic beamsplitter, the transceiver arrangement being configured for: * transmitting a source beam from the laser source to a first end of an optical fiber arrangement, in one way selected among: through or by reflection on the dichroic beamsplitter, and * transmitting the reflected beam from said first end of the optical fiber arrangement to the optical detector in the other way selected among: through or by reflection on the dichroic beamsplitter, * transmitting a source beam from the laser source to a first end of an optical fiber arrangement, in one way selected among: through or by reflection on the dichroic beamsplitter, and * transmitting the reflected beam from said first end of the optical fiber arrangement to the optical detector in the other way selected among: through or by reflection on the dichroic beamsplitter, - the optical fiber arrangement comprising a multi-clad optical fiber which comprises a core, at least one inner cladding, and an outer cladding; wherein said core is arranged to receive the source beam having a first wavelength, such that the source beam propagates in the core in said transmitting direction, and the core is further configured to generate a scanning beam from the source beam propagating in the core, wherein the scanning beam comprises at least a second wavelength which is different from the first wavelength, and said at least one inner cladding is configured to receive the reflected beam, comprising the at least second wavelength, such that the reflected beam propagates in the inner cladding in said receiving direction, said core is arranged to receive the source beam having a first wavelength, such that the source beam propagates in the core in said transmitting direction, and the core is further configured to generate a scanning beam from the source beam propagating in the core, wherein the scanning beam comprises at least a second wavelength which is different from the first wavelength, and said at least one inner cladding is configured to receive the reflected beam, comprising the at least second wavelength, such that the reflected beam propagates in the inner cladding in said receiving direction, - a scanning unit optically coupled to a second end of the optical fiber arrangement, the scanning unit being configured to steer the scanning beam to said target, and to receive the reflected beam from the target.