JPH01183180A - Semiconductor light emitting device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Summary] Regarding a semiconductor light emitting device suitable for use as a light source in optical multiplex communication, it is possible to convert the wavelength of an optical signal to another wavelength, and the wavelength is variable. The electrode to which the bias current is applied is divided into two, and an active region that starts oscillating at a specific wavelength when an input optical signal of a certain wavelength is incident, and an active region that is connected to the active region. A phase adjustment region that controls the oscillation wavelength by changing the bias current,
It is configured to have three regions, including a Bragg reflection region which is provided in series with the phase adjustment region and shifts the oscillation wavelength by changing the bias current.

[Industrial application field]

The present invention relates to a semiconductor light emitting device suitable for use as a light source in optical multiplex communication.

[Prior Art 7] Generally, in order to implement optical multiplex communication, it is necessary to convert an optical signal of a certain wavelength to another wavelength, and that the wavelength must be variable and controllable. Must be.

Conventionally, in order to achieve this, an input optical signal is first converted into an electrical signal, and the electrical signal is used to drive a semiconductor laser whose wavelength is variable and can be controlled. A method is used to convert the signal back into an optical signal and output it.

[Problem to be solved by the invention]

Currently, in order to embody the above-mentioned means, it is necessary to use individual parts, and therefore, the structure thereof becomes extremely complicated, and it is difficult to put it to general use.

If it were possible to obtain a semiconductor light-emitting device that can perform wavelength conversion on an optical signal or control the conversion wavelength to change, optical multiplex communication would make great progress toward its practical application.

The present invention aims to provide a semiconductor light emitting device that can convert the wavelength of an optical signal to another wavelength and can control the wavelength to be variable.

[Means to solve the problem]

In order to realize the desired semiconductor light emitting device, it is first necessary to provide the device with a function of converting the wavelength of an optical signal to another wavelength.

FIG. 2 is a cross-sectional side view of a main part for explaining a conventional example of a semiconductor laser in which the electrode to which a bias current is supplied is divided.

In the figure, 1 is an n-type InP cladding/substrate, 2 is an I
nGaAs P active layer, 3 is p-type InP cladding/contact layer, 4A is p-side first electrode, 4B is p-side second electrode,
5 is the n-side electrode, Ll is the length of the first electrode portion, and L2 is the first
A groove for separating the electrode part and the second electrode part, L3 is the length of the second electrode part, LIN is the input optical signal, I-out is the output optical signal, 11 and I2 are the bias currents, respectively. .

This semiconductor laser is known as a bistable laser diode (see 1985 IEICE General National Conference, Manuscript No. 886).

For this semiconductor laser, the bias currents 1+ and I2 are set to the values immediately before oscillation starts, and when an input optical signal LIN of a certain wavelength is applied in that state, oscillation starts at a specific wavelength and wavelength conversion is performed. output optical signal. It was confirmed through experiments that UT could be obtained.

In the present invention, wavelength conversion is performed by operating a semiconductor light emitting device having the structure shown in FIG. 2 under the above conditions.

Next, it is necessary to make the oscillation wavelength specific to the semiconductor laser variable and to control it.

FIG. 3 shows a cut-away, oblique view of the essential parts of a three-region semiconductor laser developed by the applicant and capable of variable and controllable wavelength.

In the figure, 11 is an n-type 1nP substrate, 12 is a grating, 13 is an n-type nGaASP guide layer, 14 is an n-type 1nP cladding layer, 15 is an InGaAsP active layer, 1
6 is an InGaAsP melt-back resistant layer, 17 is a p-type I
nP buried layer, 18 is an n-type InP buried layer, 19 is a p-type InP cladding layer, 20 is a p-type 1nP contact layer, 21 is an active region electrode, 22 is a phase adjustment region electrode, 23
is DBR (distributed Bragg).
reflector) iJl area electrode The electrode is active area, P
indicates a phase adjustment area, and D indicates a DBR area, respectively.

As can be seen from the figure, this semiconductor laser consists of three regions: a normal active region A, a phase adjustment region P, and a DBR region, and the light emitting region A has a light emission output similar to a normal semiconductor laser. In the phase adjustment region P, phase control is performed to obtain stable single wavelength oscillation.
In the D B RfJ region, the Bragg wavelength is controlled.

Now, when a constant current is applied to the active region electrode 21 to cause the light emitting region A to oscillate, the resulting output light is sent out from the end face in the D B Rfii region via the phase adjustment region P. However, in this state, if the current flowing through the phase adjustment region electrode 22 is kept constant and the current flowing through the DBR region electrode 23 is changed, the oscillation wavelength shifts to the shorter wavelength side. This is because the refractive index decreases due to carrier injection and the Bragg wavelength shifts. Furthermore, when the current flowing through the active region electrode 21 and the DBR region electrode 23 is maintained at a predetermined value, and the current flowing through the phase adjustment region electrode 22 is changed,
Since the phase conditions change, the wavelength can be continuously controlled.

In the present invention, the structure of a semiconductor light emitting device having the structure shown in FIG. 3 is adopted to make the oscillation wavelength variable and to control it.

Therefore, in the semiconductor light emitting device according to the present invention, the electrodes (for example, first electrodes 36A and 36C) to which bias currents (for example, bias currents □ and IA2) are applied are divided into two, and There is an active region (e.g. active region A) that starts oscillating at a specific wavelength when a ray (e.g. LIN) is incident, and a bias current (e.g. bias current IF) connected to the active region that can be changed to change the oscillation wavelength. A phase adjustment area that performs control (for example, a phase adjustment area P
), a Bragg reflection region (for example, a DBR region, a color region), and a Bragg reflection region (for example, a DBR region, a color region) that is provided in series with the phase adjustment region and shifts the oscillation wavelength by changing a bias current (for example, a bias current ID).

[Effect]

By adopting the above method, it is possible to convert the wavelength of the input optical signal, and also to make the wavelength variable and controllable, so it is effective as a light source for realizing optical multiplex communication. Moreover, since the entire device can be constructed monolithically, it is much smaller than conventional devices.

〔Example〕

FIG. 1 shows a cutaway side view of essential parts of one embodiment of the present invention, and FIG.
The same symbols as those used in the figures and FIG. 3 indicate the same parts or have the same meanings.

In the figure, 31 is an n-type 1nP cladding/substrate, 32 is a grating, 33 is an n-type InGaAsP waveguide layer,
34 is an InGaAsP active layer, 35 is a p-type InP cladding/contact layer, 36A is an active region first electrode, 3
6B is a separation groove, 36C is an active region second electrode, 37 is a phase adjustment region electrode, 38 is a DBR region electrode, LA is the length of active region A, LP is the length of phase adjustment region P, LD is DBR
The length of the area, IAI is the bias current supplied to the first electrode 36A, ■1 is the bias current supplied to the second electrode 36C, ■2 is the bias current supplied to the electrode 37, and In is the bias supplied to the electrode 38. Each shows the current.

Examples of various data related to the main parts in this embodiment are as follows.

tal Length LA for active area A: 300 (,17m) Thickness: 0.21
(μm) Composition λPL (wavelength conversion): 1.54 Cμm) (b
l Length LP of phase adjustment region P = 172 Cμm] Thickness: 0.23Cμm] Composition λPL: 1. , 29 C'll m) (CI
Length of DBR region: 290 Cμm] Thickness: 0.23 (μm) Composition λPL: 1.29 Cμm) In such a semiconductor light emitting device, bias current 1a+: 51, 5 (mA) bias Current I A2: 2,05 (mA) Bias current IF: 0.1 (mA) Bias current In: 0.1 (mA), input optical signal LIN, Wavelength: 1.531 (μm) Waveform :Pulse peak value: 0.66 (mW) When input, the output optical signal is obtained. As LIT, wavelength: 1.534Cμm] Waveform: Pulse peak value: 2.7 (mW) Rise and fall: 1. 5 (ns).In addition, the output wavelength was 1.530 (μm
] to 1.534 Cμm].

〔Effect of the invention〕

The semiconductor light emitting device according to the present invention includes an active region that starts oscillating at a specific wavelength when an input optical signal of a certain wavelength is incident, a phase adjustment region that controls the oscillation wavelength, and a phase adjustment region that shifts the oscillation wavelength. It has a Bragg reflection region.

By adopting the above configuration, it is possible to convert the wavelength of an input optical signal, and also to make the wavelength variable and controllable, so it is effective as a light source for realizing optical multiplex communication. Moreover, since the entire device can be constructed monolithically, it is much smaller than conventional devices.

[Brief explanation of the drawing]

FIG. 1 is a cutaway side view of the main part of an embodiment of the present invention, FIG. 2 is a cutaway side view of the main part of a semiconductor laser with two divided electrodes, and FIG. 3 is a cutaway side view of the main part of a semiconductor laser with three regions. each represents. In the figure, 31 is an n-type InP cladding/substrate, 32 is a grating, 33 is an n-type 1nGaAsP waveguide layer, 3
4 is an InGaAsP active layer, 35 is a p-type 1nP cladding/contact layer, 36A is an active region first electrode, 36
B is a separation groove, 36C is an active region second electrode, 37 is a phase adjustment region electrode, 38 is a DBR region electrode, LA is an active region A
Length, L. is the length of the phase adjustment area P, Lo is the length of the DBR area,
IAI is the bias current supplied to the first electrode 36A, IA
II indicates the bias current supplied to the second electrode 36C, ■ indicates the bias current supplied to the electrode 37, and 1 indicates the bias current supplied to the electrode 38. Patent applicant: Fujitsu Ltd. Representative Patent Attorney Shoji Aitani Representative Patent Attorney Hiroshi Watanabe −

Claims (1)

[Claims] An electrode for applying a bias current is divided into two parts, and includes an active region that starts oscillating at a specific wavelength when an input optical signal of a certain wavelength is input, and an active region that is connected to the active region and that applies a bias current. A semiconductor light emitting device comprising three regions: a phase adjustment region that controls the oscillation wavelength by changing the phase adjustment region, and a Bragg reflection region that is provided in series with the phase adjustment region and shifts the oscillation wavelength by changing the bias current.