Semiconductor laser module driven in shunt-driving configuration

Abstract

The present invention is to provide a laser module stably operable with less jitter in high frequencies. The laser module of the invention provides a semiconductor laser diode and a current-shunting device that shunts the current flowing in the LD by responding the input modulation signal. A path where the current flows puts a serial circuit comprised of an inductor and a compensation circuit to compensate a ripple in the frequency response of the module. The resonance frequency of the compensation circuit corresponds to a frequency of a dip or a peak in the frequency spectrum of the module.

Description

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a perspective view of a laser module according to an embodiment of the present invention;

FIG. 2 is an equivalent circuit diagram of the laser module shown in FIG. 1;

FIG. 3 is a frequency response, S21, of a laser module without a compensation circuit;

FIG. 4 is an impedance characteristic of the compensation circuit;

FIG. 5 is a frequency response, S21, of a laser module with the compensation circuit according to an embodiment of the present invention; and

FIGS. from 6A to 6D show various eye-diagrams.

Claims

1. A semiconductor laser module with a shunt-driving configuration, comprising: a semiconductor laser diode;an electronic device connected in parallel to the laser diode, the electronic device switching a current to be supplied to the laser diode by responding to a modulation signal;a first inductor put on a path for supplying the current to the laser diode; anda compensation circuit connected in serial to the inductor, the compensation circuit compensating a frequency response of the current with respect to the modulation signal input to the electronic device,wherein the compensation circuit is serially connected to the inductor and a composite circuit of the compensation circuit with the inductor is connected in serial to the laser diode and to the electronic device.

2. The laser module according to claim 1, further comprising a CAN package including a stem for mounting the laser diode, the electronic device, the first inductor and the compensation circuit thereon, and first and second lead pins each passing through the stem,wherein the first lead pin is connected to the path to supply the current and the second lead is connected to the electronic device to supply the modulation signal thereto.

3. The laser module according to claim 2, wherein the first inductor is mounted on the first lead pin.

4. The laser module according to claim 2, wherein the stem includes a mount and the laser module further includes a heat sink, andwherein the laser diode is mounted on a side wall of the mount through the heat sink.

5. The laser module according to claim 4, wherein the compensation circuit is mounted on the heat sink.

6. The laser module according to claim 4wherein the electronic device is directly mounted on a side wall of the mount.

7. The laser module according to claim 1, wherein the compensation circuit has impedance to compensate the frequency response of the current.

8. The laser module according to claim 7, wherein the compensation circuit includes second inductor, a capacitor, and two resistors, one of which is connected in serial to the capacitor, the other of which is connected in parallel to the second inductor and to the serial circuit of the capacitor and one of the resistors.

9. The laser module according to claim 1, wherein the compensation circuit is integrated in the electronic device.