Sumitomo Electric Industries, Limited

Akihiro Moto

Hideo Itozaki

Keiji Tanaka

Hisao Go

Toshiaki Kihara

Eiji Tsumura

Kiyoshi Kato

Kenjiro Higaki

Tatsuoki Nagaishi

So Tanaka

Katsumi Uesaka

Yoshiyuki Sugimoto

Tomokazu Katsuyama

Tatsuya Tanabe

Nobuyuki Ikoma

A driver for an EA-DFB device includes a switching device. The EA-DFB device is put between a positive power supply and a negative power supply as connected in series to a bias current source and the switching device. The EA device is modulated by the switching device in the differential mode. The switching device includes paired transistors each having a load, one of which is a resistor connected in parallel to the EA device, while, the other is constituted by a resistive element.

Driver for laser diode integrated with external modulator

A laser diode (LD) driver to suppress the excess emission of an LD is disclosed. The LD driver has the shunt configuration with a driving transistor connected in parallel to the LD to shunt the bias current provided to the LD. The driver further provides a protection circuit to divide the bias current when the bias current is active but the driving transistor is turned off at an instant of the power on and off of the LD driver.

Optical transmitter suppressing excess emission of laser diode

A differential circuit with a function to compensate the gain enhancement due to the self-heating of the transistor is disclosed. The differential circuit includes an equalizer unit coupled with one of paired transistors. The other of the paired transistor receives the input signal to be amplified. The base level, or the base-emitter bias, is oppositely modulated by the input signal through the common emitter, which causes the modification of the base current. The equalizer unit reduces the variation of the base level only in low frequencies where the self-heating effect of the transistor appears.

Differential circuit compensating gain enhancement due to self heating of transistors

A shunt driver for driving an LD is disclosed. The shunt driver has the push-pull arrangement with the high side driver and the low side driver. The high side driver is driven by a positive phase signal superposed with a negative phase signal with a delay and a less amplitude with respect to the positive phase signal. The low side driver is driven by a negative phase signal superposed with a positive signal with a delay and a less amplitude compared to the positive phases signal. Adjusting the magnitude of the superposed signals, the driving current for the LD has the peaking in the rising and falling edges thereof.

Driver circuit for laser diode outputting pre-emphasized signal

A shunt driver for driving an LD is disclosed. The shunt driver has the push-pull architecture with the high side driver and the low side driver. The high side driver is driven by a positive phase signal superposed with a signal with a phase opposite to the negative phase signal. The low side driver is driven by a negative phase signal superposed with a signal with a phase opposite to the positive phase signal. Adjusting the magnitude of the superposed signals, the driving current for the LD has the peaking in the rising and falling edges thereof.

Shunt driver circuit for laser diode with push pull architecture

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.

Laser driver and optical transmitter implementing the same

A trans-impedance amplifier (TIA) for a light-receiving circuit is disclosed where the TIA reduces the power consumption as suppressing the degradation of the signal quality in high frequency regions. The TIA comprises a primary core, a dummy core, and a differential amplifier that receives each output of two cores in the differential mode. Two cores have an arrangement substantially same to each other except that the power consumption thereof is smaller in the dummy core. Because the output impedance of two cores becomes substantially equal, the scattering parameter of the common mode to the differential mode at the output of the primary core becomes small enough.

Light receiving circuit with differential output

A driver circuit for a semiconductor laser diode (LD) is disclosed, in which the driver circuit drives the LD in the differential mode and lowers the power consumption thereof. The driver circuit includes a differential unit to provide the modulation current to the LD, a voltage converter to provide a positive power supply to the differential unit, a detector to detect the common mode voltage of the differential outputs of the unit, and a comparing unit to control the voltage converter dynamically such that the output common mode voltage is set in a preset reference level.

Driver circuit for semiconductor laser diode driven in differential mode

A driver circuit for the laser diode is disclosed. The driver circuit has the shunt configuration with a switching transistor connected in parallel to the laser diode to shunt the current flowing in the laser diode. In the present invention, the bias for the switching transistor is varied as the operating temperature of the laser diode. In addition, the gate bias for the switching transistor is compensated for the temperature dependence of the switching transistor.

Shunt driver circuit for semiconductor laser diode

The present invention is to provide alight emitting module that improves the positional precision of a semiconductor laser diode. A light emitting module of the present invention is configured with a semiconductor laser diode having a facet which inputs, or outputs light; an integrated circuit which is electrically connected to the semiconductor laser diode; and a package which mounts the semiconductor laser diode and the integrated circuit therein. The semiconductor laser diode is mounted on the integrated circuit, and the integrated circuit has a marker. The marker is utilized in determining a position of the semiconductor laser diode with respect to the integrated circuit, and further in determining a position of the semiconductor laser diode with respect to the package.

Optical transmitting module including laser diode mounted on driver circuit

The present invention provides an optical transmitting module, in which a laser diode and a termination resistor are provided without sizing up the package thereof and degrading the thermal characteristic due to heat generation by the termination resistor. The transmitting module of the present invention includes the semiconductor laser diode, and the resistor. The laser diode is mounted on the side surface of the block extruding from the base. The resistor is mounted on the flat side portion of the end of the lead. The lead is secured in the through hole provided in the base with seal glass being filled in the gap between the through hole and the lead. In the transmitting module thus configured, the laser diode is thermally isolated from the heat generated by the resistor due to the seal glass.

Can-type optical transmitting module utilizing a laser diode with impedance matching resistors

The laser diode of the present invention is mounted on the heat sink made of insulating material such as aluminum nitride (AlN). On the heat sink, a metal film, evaporated gold film, is provided and the laser diode is mounted on the heat sink such that the anode electrode of the laser diode faces and is in contact with the metal film. The heat sink is mounted on the grounded metal member, thus the metal member, the heat sink and the metal film forms an capacitor. The bias for the laser diode is provided via the metal film, thereby stabilizing the bias supply even when the operational frequency for the laser diode is over 10 Gbps.

Light-transmitting module capable of responding a high-frequency over 10 GHz

The present invention provides an optical transmitting module capable of outputting a signal for precisely controlling bias and modulation current, and a transmitting optical sub-assembly using the same. The optical transmitting module of the invention builds a semiconductor laser diodeand a temperature sensor within a CAN type package. The CAN type package includes a base, a block provided on the base and mounting the laser diode on a side thereof, and a plurality of leads secured to the base. The laser diode is supplied current signal Sthrough one of leads, while the temperature sensor outputs a signal Sthrough the other of leads. The temperature sensor is mounted immediately close to the laser diode, accordingly, capable of monitoring the temperature of the laser diode.

Optical transmitting module having a can type package and providing a temperature sensor therein

The present invention provides an optical transmitting module or optical transmitting sub-assembly in which an inductor for de-coupling the bias circuit of the semiconductor laser diode is built. The laser diode is mounted on the side surface of the block provided on the stem, while the inductor is installed on the lead, which is secured by the stem, such that one electrode of the inductor is in contact to the lead and the other electrode of the inductor is connected to an electrode of the laser diode. The electrode of the laser diode is also connected to the other lead. Thus, the electrode of the laser diode is connected to two leads, one of which is through the inductor.

Optical transmitting module having a de-coupling inductor therein

A light-transmitting module of the present invention includes a light-emitting device such as a laser diode (LD), a transistor for shunting-drive the LD and a CAN type package with a base and an electrically conductive block. The LD and the transistor are mounted on a side of the block in side-by-side arrangement such that the LD substantially positions a center of the package. One of the current terminals of the transistor and one electrode of the LD are connected via the conductive block. The other of the current terminal of the transistor and the other of the electrodes of the LD are connected to one lead, while the control terminal of the transistor is connected to the other lead. Since the present module includes the transistor within the CAN type package, the size thereof may be miniaturized, and the quality of the optical output can be enhanced.

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Yokohama, Japan

Akihiro Moto