Patent ID: 7657182

Claim:
An optical transmitter system comprising: an optical receiver; and an optical transmitter which transmits an optical signal to the optical receiver through free space, the optical transmitter comprising: an electrical-to-optical converting unit for converting a first electrical signal to be transmitted into an optical signal, and emitting the optical signal; a diffusing liquid lens including a first liquid and a second liquid, the first and second liquids being separated in order in a propagation direction along an optical axis of the electrical-to-optical converting unit and forming a convex boundary surface having a curvature, the convex boundary surface being formed in the propagation direction of the optical signal, and a scattering material being mixed in the first liquid to scatter light, the curvature of the boundary surface being changed based on a control voltage being applied to the diffusing liquid lens; a controlling unit for adjusting the control voltage applied to the diffusing liquid lens, a transmitting unit for receiving a data signal, and generating the first electrical signal based on the data signal; a reflected light receiving unit for receiving a reflected optical signal, the reflected optical signal being part of the optical signal reflected from the optical receiver, and converting the reflected optical signal into a second electrical signal; and a delay time calculating unit for calculating a delay time of the second electrical signal from the first electrical signal, and outputting a delay signal representative of the delay time to the controlling unit, wherein the controlling unit adjusts the control voltage based on the delay signal, wherein the transmitting unit includes: a timing signal generating unit for outputting a predetermined timing signal; and an adding unit for adding the data signal and the predetermined timing signal together to thereby generate the first electrical signal, and the delay time calculating unit calculates the delay time based on a difference between detection times of the predetermined timing signal outputted from the timing signal generating unit and a timing signal contained in the second electrical signal, and wherein the timing signal generating unit repetitively outputs a series of timing signals that are different in amplitude level from each other and are smaller in pulse width than the data signal.