Laser data transmitter with wide frequency bandwidth

Claim 2

A laser transmitter for transmitting information signals from an information signal source comprising a carrier wave laser for providing a laser beam of intensity proportional to the electrical energizing current passed through said laser, modulator means responsive to said information signal and coupled with said laser for amplitude modulating said energizing current in accordance with said information signal thereby amplitude modulating said laser beam in accordance with said information signal, said laser exhibiting a high frequency rolloff in its frequency versus percent amplitude modulation characteristic of said beam with regard to said energizing current, and pre-emphasis means coupled with said modulator means for providing high frequency pre-emphasis with respect to said information signal, said high frequency pre-emphasis having an inverse characteristic to that of said high frequency rolloff for providing a wide frequency bandwidth laser information signal transmitter with a substantially flat frequency response over said wide frequency bandwidth.

Claim 3

The transmitter of claim 1 in which said modulator means comprises a current modulator connected in series circuit with said laser.

Claim 4

The transmitter of claim 2 in which said current modulator comprises a high frequency, high gain triode including cathode, anode and control grid electrodes, said cathode and anode electrodes being connected in series circuit with said laser for passage of said energizing current therebetween and said control grid electrode being coupled to receive said information signal for amplitude modulation of said energizing current in accordance therewith, and said pre-emphasis means comprises a high pass shaping filter coupled to receive said information signal for shaping said information signal in accordance with said inverse characteristic and coupled to provide said shaped signal to said cathode electrode thereby providing said high frequency pre-emphasis.

Claim 5

The transmitter of claim 2 in which said current modulator comprises a high frequency, high gain triode including cathode, anode and control grid electrodes, said cathode and anode electrodes being connected in series circuit with said laser for passage of said energizing current therebetween and said control grid electrode being coupled to receive said information signal for amplitude modulation of said energizing current in accordance therewith, and said pre-emphasis means comprises a bypass capacitor in series circuit with said cathode of such impedance that bypassing is incomplete at the lower frequencies thereby providing said high frequency pre-emphasis.

Claim 6

A laser transmitter for transmitting information signals from an information signal source comprising a carrier wave gas laser including a gas tube for providing a laser beam of intensity proportional to the electrical energizing current passed through said gas tube, a high frequency, high gain triode current modulator including cathode, anode and control grid electrodes, said cathode and anode electrodes being connected in series circuit with said gas tube for passage of said energizing current therebetween and said control grid electrode being coupled to receive said information signal for amplitude modulating said energizing current in accordance with said information signal thereby amplitude modulating said laser beam in accordance with said information signal, said laser exhibiting a high frequency rolloff in its frequency versus percent amplitude modulation characteristic of said beam with regard to said energizing current, and pre-emphasis means comprising a high pass shaping filter coupled to receive said information signal for shaping said information signal in accordance with a characteristic inverse to that of said high frequency rolloff and coupled to provide said shaped signal to said cathode electrode for providing high frequency pre-emphasis with respect to said information signal to provide a wide frequency bandwidth laser information signal transmitter with a substantially flat frequency response over said wide frequency bandwidth.

Claim 7

A laser transmitter for transmitting information signals from an information signal source comprising a carrier wave gas laser including a gas tube for providing a laser beam of intensity proportional to the electrical energizing current passed through said gas tube, a high frequency, high gain triode current modulator including cathode, anode and control grid electrodes, said cathode and anode electrodes being connected in series circuit with said gas tube for passage of said energizing current therebetween and said control grid electrode being coupled to receive said information signal for amplitude modulating said energizing current in accordance with said information signal thereby amplitude modulating said laser beam in accordance with said information signal, said laser exhibiting a high frequency rolloff in its frequency versus percent amplitude modulation characteristic of said beam with regard to said energizing current, and pre-emphasis means comprising a high pass shaping filter coupled to receive said information signal for shaping said information signal in accordance with a characteristic inverse to that of said high frequency rolloff and coupled to provide said shaped signal to said cathode electrode for providing high frequency pre-emphasis with respect to said information signal to provide a wide frequency bandwidth laser information signal transmitter with a substantially flat frequency response over said wide frequency bandwidth.