JP3196791B2 - Tunable semiconductor light emitting device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wavelength tunable semiconductor light emitting device in a semiconductor light source used for systems such as optical communication, optical information processing, and optical measurement.

[0002]

2. Description of the Related Art A wavelength tunable semiconductor light emitting device in which a mirror provided in a system for optical communication, optical information processing, optical measurement, etc. is directly operated to change a cavity length employs a surface emitting semiconductor laser and an external mirror. Stuff already proposed
(N. Yokouchi et al. IEEE Photonics Tochnology Letter
s, vol. 4, no. 7, 701 (1992)). FIG. 5 is a schematic perspective view of a conventional wavelength variable semiconductor light emitting device.

As shown in FIG. 5, a surface emitting semiconductor laser 102 is formed on
An external mirror 104 is formed on a plastic plate 103 attached to the semiconductor laser 10.
A resonator is formed by one of the two surfaces and the external mirror 104, and the plastic plate 103 is pressed by the tuning rod 105 to displace the external mirror 104 in the direction of the optical axis, thereby changing the resonator length, thereby increasing the longitudinal mode. Control can be performed.

[0004]

In such a conventional wavelength tunable semiconductor light emitting device, the external mirror 104 is constituted by a bulk component, and its adjustment is performed by the tuning rod 1.
This is performed externally by a piezo or the like via the external device 05. Therefore, an external drive mechanism for adjusting the external mirror 104 is required, which causes a problem that the structure becomes complicated and the device itself becomes large.

[0005] Further, since all of the wavelength tunable semiconductor light emitting devices are composed of individual components, there is a problem that the assembly impairs mass productivity and lacks economy. Further, the entire modulator including the external drive mechanism for adjusting the external mirror 104 described above becomes large, resulting in poor space efficiency.
There was also a limitation on the frequency increase due to the actuator size of the drive mechanism.

The present invention solves the above-mentioned problems, and solves the problems such as mass productivity, economic efficiency, and restrictions on the use of higher frequencies due to the external drive mechanism and individual components of a conventional wavelength-variable semiconductor laser. It is an object of the present invention to provide a tunable semiconductor light emitting device as a small, inexpensive, and high-performance tunable light source.

[0007]

According to a first aspect of the present invention, there is provided a wavelength tunable semiconductor light emitting device, comprising: a semiconductor laser; an external mirror; and a microactuator for driving the external mirror in an optical axis direction of the semiconductor laser. Wherein the external mirror and the microactuator are formed on a substrate on which the semiconductor laser is mounted.

Further, the wavelength tunable semiconductor light emitting device of the present invention is a wavelength tunable semiconductor light emitting device comprising a semiconductor laser, an external mirror, and a microactuator for driving the external mirror in the optical axis direction of the semiconductor laser. The laser, the external mirror, and the microactuator are formed on the same substrate.

[0009]

The external mirror and its driving mechanism are integrally formed on the same substrate by the micro-machining technology, so that the external mirror and the driving mechanism and the substrate or the semiconductor laser can be collectively produced in the same manner as in the photolithography technology LSI process. In addition, the number of assembling steps is remarkably reduced as compared with the conventional one, so that the mass productivity and the economical efficiency of the element can be greatly improved, and the frequency can be increased by miniaturizing the actuator.

[0010]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a schematic perspective view of a wavelength tunable semiconductor light emitting device according to an embodiment of the present invention, and FIG. 2 is a schematic view showing a process of manufacturing the wavelength tunable semiconductor light emitting device.

As shown in FIG. 1, the wavelength tunable semiconductor light emitting device of the present embodiment is of a hybrid type, and a semiconductor laser 12 is bonded on a Si substrate 11 of about 500 μm × 500 μm for heat sink. A movable doubly supported beam 14 forming an external mirror 13 is formed in the vicinity of one of the resonator surfaces. This doubly supported beam 14 is a partially formed insulating film 15.
It has an anchor 16 on the top, one side of which is vertical and forms an external mirror 13. The other side surface has at least one uneven comb-shaped portion 17, and a fixed uneven comb-shaped portion 18 is formed on the insulating film 15 so as to face the comb-shaped portion 17. Thus, the microactuator 19 is configured.

Accordingly, the electrode pad 2 is provided on the semiconductor laser 12.
In addition, electrode pads 21 and 22 are attached to the movable doubly supported beam 14 and the fixed comb-shaped portion 18, respectively, and a voltage is applied between the two. Is driven, the external mirror 13 that reflects the laser light is displaced in the optical axis direction, and the longitudinal mode can be controlled.

Such a wavelength tunable semiconductor laser device is
For example, it is manufactured by the following method. FIG. 2 (a)
(G), first, an insulating film 1 is formed on a Si substrate 11.
After forming 5, a step 23 for bonding the semiconductor laser 12 is formed by, for example, different direction wet etching. Next, a sacrificial layer 23 is formed at a position where the movable doubly supported beam 14 is to be formed. Actuator layers 25, 2
6 is deposited and the movable and fixed portions are patterned.
Then, the sacrificial layer 24 is etched, and
Is a movable shape. Here, after dicing the Si substrate 11 into a chip shape, the semiconductor laser 12 having an antireflection coating 27 on one end face is bonded.

FIG. 3 is a schematic perspective view of a wavelength variable semiconductor light emitting device according to another embodiment of the present invention.

As shown in FIG. 3, the wavelength tunable semiconductor light emitting device of this embodiment is of a monolithic type and has a semiconductor insulating substrate (GaAs, InP) for forming a laser layer.
A movable laser beam 34 and a fixed electrode 35 on which a semiconductor laser 32, an external mirror 33 constituting a microactuator 49 are formed, are monolithically formed on 31, and have a size of about 500 μm × 500 μm.

Such a wavelength tunable semiconductor laser device is
For example, it is manufactured as follows. First, after a layer serving as the lower conductive layer 36 of the semiconductor laser 32 is grown on the semiconductor insulating substrate 31, a normal semiconductor laser layer 37 is crystal-grown. Next, the movable cantilever 34 and the fixed comb-shaped portion (electrode) 35 constituting the actuator portion 49 and the semiconductor laser 3
The second etched mirror 38 is patterned, and is etched by reactive dry etching to a depth reaching the semiconductor insulating substrate 31. And the etched mirror 3
After the surface 8 is coated with an anti-reflection film by an oblique deposition method or the like, the surface for forming the lower electrode of the semiconductor laser 32 is exposed by etching. Further, upper and lower electrode (P, N) pads 39, 40 of the semiconductor laser 32
And after forming the actuator electrode pads 41 and 42,
The lower sacrificial layer of the doubly supported beam 34 is etched to cover the portion of the semiconductor laser 32, and finally the chip is divided by cleavage. The wavelength tunable semiconductor light emitting device of this embodiment has an advantage that the assembly process of the laser and the external mirror can be performed collectively as compared with the above-described device.

FIG. 4 is a plan view showing various patterns of the microactuator. FIG. 4A shows the simplest shape, in which a concave portion is formed on the movable beam 42 side of the substrate 41 and a convex portion that enters the concave portion is formed on the fixed portion 43 side. It is. Reference numeral 44 denotes a semiconductor laser. As shown in FIG. 4B, the movable beam 45 side and the fixed portion 46 side are each formed in a comb shape as described above in order to reduce the applied voltage.

FIG. 4 (c) shows a structure in which fixed portions 48, 49 are formed on both sides of a movable beam 47 and drive electrodes 50, 49 so that the movement of the movable beam can be further finely adjusted.
The movable beam 47 can be driven back and forth and a slight inclination can be adjusted. Note that the shape of the driving unit is not limited to the above.

[0020]

As described above in detail with the embodiments, according to the wavelength tunable semiconductor light emitting device of the present invention, whether the external mirror and the microactuator are formed on the substrate on which the semiconductor laser is mounted, In addition, since the semiconductor laser, the external mirror, and the microactuator are formed on the same substrate, there is no need to assemble the individual components of the device,
The mass production and economic efficiency of the element can be greatly improved, and the actuator is very small, so that high-speed driving is possible and the frequency of the element can be increased, and the driving power of the actuator is small. Labor saving of the whole apparatus can be achieved.

[Brief description of the drawings]

FIG. 1 is a schematic perspective view of a wavelength tunable semiconductor light emitting device according to one embodiment of the present invention.

FIG. 2 is a schematic view of a forming process showing a method of manufacturing a wavelength-tunable semiconductor light emitting device.

FIG. 3 is a schematic perspective view of a wavelength variable semiconductor light emitting device according to another embodiment of the present invention.

FIG. 4 is a plan view showing various patterns of the microactuator.

FIG. 5 is a schematic perspective view of a conventional wavelength variable semiconductor light emitting device.

[Explanation of symbols]

11, 31 Substrate 12, 32 Semiconductor laser 13, 33 External mirror 14, 34 Movable beam 15 Insulating film 18, 35 Fixed comb 19, 49 Microactuator 20, 21, 22, 39, 40, 41, 42 Electrode pad

Continuation of the front page (56) References JP-A-5-37082 (JP, A) JP-A-2-106854 (JP, U) Tables JP-A-8-500468 (JP, A) (58) Fields investigated (Int) .Cl. ⁷ , DB name) H01S 5/00-5/347

Claims (2)

(57) [Claims] 1. A wavelength tunable semiconductor light emitting device comprising: a semiconductor laser; an external mirror; and a microactuator for driving the external mirror in an optical axis direction of the semiconductor laser, wherein the external mirror and the microactuator are the semiconductor laser. A wavelength tunable semiconductor light emitting device, which is formed on a substrate on which is mounted. 2. A wavelength tunable semiconductor light emitting device comprising a semiconductor laser, an external mirror, and a microactuator for driving the external mirror in the optical axis direction of the semiconductor laser, wherein the semiconductor laser, the external mirror, and the microactuator Are formed on the same substrate.