# US 8,571,078 B2 · Laser driver and optical transmitter implementing the same > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,571,078 B2 - Document ID: US8571078B2 - Status: Granted - Kind: B2 - Application number: 13/282,131 - Filed: 2011-10-26 - Published: 2012-05-03 - Granted: 2013-10-29 - Earliest claimed: 2010-10-28 - Assignees: Sumitomo Electric Industries, Ltd. - Applicants: Akihiro Moto; Keiji Tanaka - Inventors: Akihiro Moto; Keiji Tanaka - Web page: https://patentgrep.com/patent/US8571078B2 ## CPC - H01S 5/0428: {for applying pulses to the laser} - H03K 17/60: the devices being bipolar transistors (bipolar transistors having four or more electrodes H03K17/72) - H03K 17/6871: {the output circuit comprising more than one controlled field-effect transistor} - H01S 5/06216: {Pulse modulation or generation} - H01S 5/06226: {Modulation at ultra-high frequencies} - H01S 5/0683: by monitoring the optical output parameters - H01S: DEVICES USING THE PROCESS OF LIGHT AMPLIFICATION BY STIMULATED EMISSION OF RADIATION [LASER] TO AMPLIFY OR GENERATE LIGHT; DEVICES USING STIMULATED EMISSION OF ELECTROMAGNETIC RADIATION IN WAVE RANGES OTHER THAN OPTICAL - H03K: PULSE TECHNIQUE (measuring pulse characteristics G01R; modulating sinusoidal oscillations with pulses H03C; transmission of digital information H04L; discriminator circuits detecting phase difference between two signals by counting or integrating cycles of oscillation H03D3/04; automatic control, starting, synchronisation or stabilisation of generators of electronic oscillations or pulses where the type of generator is irrelevant or unspecified H03L; coding, decoding or code conversion, in general H03M) ## Abstract An LD-Driver with the push-pull arrangement is disclosed. The driver includes the high side driver driven by the positive phase signal and the low side driver driven by the negative phase signal. When the positive phase signal is in HIGH, the high side driver becomes ON and the LD driver provides additional current to the bias current for the LD; while, when the negative phase signal is in HIGH, the low side driver becomes ON and the LD driver extracts a portion of the bias current for the LD. ## Claims ### Claim 1 A laser diode driver to drive a semiconductor laser diode, the driver being driven with a positive phase signal and a negative phase signal complementary to each other, comprising: a high side driver including a series circuit of a first MOSFET and a second MOSFET, the first MOSFET having a conducting type different from a conducting type of the second MOSFET, the first MOSFET being driven by the positive phase signal, the high side driver providing a positive current to the semiconductor laser diode when the positive phase signal is in HIGH; and a low side driver driven by the negative phase signal, the low side driver extracting a negative current from the semiconductor laser diode. ### Claim 2 (depends on 1) The laser diode driver of claim 1, wherein the second MOSFET is fixedly biased. ### Claim 3 (depends on 1) The laser diode driver of claim 1, wherein the second MOSFET is driven by the negative phase signal. ### Claim 4 (depends on 1) The laser diode driver of claim 1, wherein the low side driver includes a third MOSFET driven by the negative phase signal. ### Claim 5 (depends on 4) The laser diode driver of claim 4, wherein the low side driver further includes an emitter follower to receive the negative phase signal, and wherein the third MOSFET is coupled with the emitter follower in DC mode. ### Claim 6 (depends on 1) The laser diode driver of claim 1, wherein the low side driver includes a bipolar transistor driven by the negative phase signal. ### Claim 7 (depends on 6) The laser diode driver of claim 6, wherein the low side driver includes an emitter follower to receive the negative phase signal, and wherein the bipolar transistor is coupled with the emitter follower in DC mode. ### Claim 8 An optical transmitter, comprising: a semiconductor laser diode; a bias current source to provide a bias current to the laser diode; a driver driven by a positive phase signal and a negative phase signal complementary to each other, the driver including, a high side driver including a series circuit of a first MOSFET and a second MOSFET, the first MOSFET having a conducting type different from a conducting type of the second MOSFET, the first MOSFET being driven by the positive phase signal to add a positive current to the bias current when the positive signal is in HIGH, and a low side driver driven by the negative phase signal to extract a negative current from the bias current when the negative signal is in HIGH. ### Claim 9 (depends on 8) The optical transmitter of claim 8, wherein the second MOSFET is fixedly biased. ### Claim 10 (depends on 8) The optical transmitter of claim 8, wherein the second MOSFET is driven by the negative phase signal. ### Claim 11 (depends on 8) The optical transmitter of claim 8, wherein the low side driver includes a third MOSFET driven by the negative phase signal. ### Claim 12 (depends on 11) The optical transmitter of claim 11, wherein the low side driver further includes an emitter follower to receive the negative phase signal, the third MOSFET being coupled with the emitter follower in DC mode. ### Claim 13 (depends on 8) The laser diode driver of claim 8, wherein the low side driver includes a bipolar transistor driven by the negative phase signal. ### Claim 14 (depends on 13) The laser diode driver of claim 13 wherein the low side driver includes an emitter follower to receive the negative phase signal, the bipolar transistor being coupled with the emitter follower in DC mode.