JPH0223734A - Optical communication system - Google Patents

Abstract

PURPOSE:To reduce cost and power consumption in an optical communication system by inputting an output from a second optical output modulation means to a secondary higher harmonic generation means, setting the optical wavelength to 1/2 and adding the output of a first optical output modulation means and the output of the secondary higher harmonic generation means to an optical wavelength multiplex means. CONSTITUTION:The optical output of an LED element 10 is added to an optical distributor 15, and the output is divided into two wavelengths, which are respectively given to optical switches 35 and 45. Respective data (1) and (2) are given to optical switch circuits 30 and 40 and the switches 35 and 45 are on/off- controlled. A higher harmonic generation crystal 90 is connected to the output of the switch 45, and second higher harmonic optical signal data of an input frequency is generated here. Data on the output of the crystal 90, lambda2 (0.8mum), for example, and data on the output lambda1 (1.6mum) of the optical switch 35 are transmitted to a wave synthesizer 50, whereby lambda1 and lambda2 are multiplexed. On the other hand, a wave-synthesizer 60 on a reception side separates data, which are respectively added to PIN diodes 70 and 80, changes them into data of electric signals for reception.

Description

[Detailed Description of the Invention] [Summary] The purpose of the present invention is to provide an optical wavelength multiplexing communication system that achieves low cost and low power consumption. In an optical transmission system having an optical wavelength multiplexing means for wavelength multiplexing optical inputs of wavelengths, a light emitting element that emits light at a predetermined wavelength;
a light distribution means connected to the light emitting element and distributing the light output of the light emitting element; first and second light output modulation means respectively connected to the light distribution means and performing predetermined modulation on the optical input based on data; , a second harmonic generating means connected to the second optical output modulating means and outputting the input optical wavelength at 172, the output of the first optical output modulating means and the output of the second harmonic generating means are provided. In addition to the optical wavelength multiplexing means, the optical wavelength multiplexing means is configured to perform optical wavelength multiplexing, and (2) has an optical wavelength multiplexing means for wavelength multiplexing optical inputs of a plurality of wavelengths each modulated by independent data. In an optical transmission system, a laser diode that emits light at a predetermined wavelength and has two output lights, and a first laser diode that inputs each of the two output lights of the laser diode and performs predetermined modulation on the optical input using data. and second-order harmonic generation means connected to the second optical output modulating means and outputting a halved input optical wavelength; The output and the output of the second harmonic generation means are added to the optical wavelength multiplexing means to perform optical wavelength multiplexing.

[Industrial application field]

The present invention relates to improvements in optical wavelength multiplexing communication systems.

At this time, there is a demand for an optical communication system that is low in cost and low in power consumption.

[Conventional technology]

FIG. 5 is a block diagram showing the configuration of a conventional example.

In the optical communication system multiplexing two wavelengths (λ1, λ2) shown in FIG. 1). Similarly, data ■ is added to the drive circuit 4, and the wavelength λ2 is
(eg 0.8 μm) to modulate the light output of the LED 2 emitting light.

The output of the LEII 1.2 is added to a multiplexer (hereinafter referred to as Sogo) 5, and multiplexed optical signal data of wavelengths λ3 and λ2 is sent out to an optical fiber.

On the other hand, on the receiving side, the input multiplexed optical signal data of wavelengths λ1 and λ2 is separated in a demultiplexer (hereinafter referred to as a demultiplexer) 6, and is sent to a light receiving element (for example, a PIN diode) 7. Convert it to a signal and receive it. In this way, optical signal data was transmitted and received.

[Problem to be solved by the invention]

However, in the above configuration, two light emitting elements are required for multiplexing two wavelengths, and since the light emitting elements are modulated by turning on and off the current, power consumption is large.Furthermore, the light emitting elements are expensive and require many adjustment steps. There were problems such as this.

Therefore, it is an object of the present invention to provide an optical communication system with lower cost and lower power consumption.

[Means to solve the problem]

The above problem is solved by the circuit configuration shown in FIG.

That is, in FIG. 1 (Part 1), in an optical transmission system including an optical wavelength multiplexing means 500 that wavelength-multiplexes optical inputs of a plurality of wavelengths modulated by independent data, 1
00 is a light emitting element that emits light at a predetermined wavelength. 150 is a light distribution means connected to the light emitting element and distributing the light output of the light emitting element.

300 and 400 are respectively connected to the optical distribution means and perform predetermined modulation on the optical input according to data.
This is an optical output modulation means.

Reference numeral 900 is a second harmonic generation means connected to the second optical output modulation means, which converts the input optical wavelength to 172 and outputs it. The output of the first optical output modulating means and the output of the second harmonic generating means are added to the optical wavelength multiplexing means to perform optical wavelength multiplexing.

Further, in FIG. 1 (part 2), in an optical transmission system having an optical wavelength multiplexing means 510 for wavelength multiplexing optical inputs of a plurality of wavelengths modulated by independent data, 11
0 is a laser diode that emits light at a predetermined wavelength and has two output lights.

Reference numerals 310 and 410 denote first and second optical output modulating means that input each of the two output lights of the laser diode and perform predetermined modulation on the optical input based on data.

Reference numeral 910 is a second harmonic generation means connected to the second optical output modulation means, which converts the input light wavelength to 172 and outputs it. The output of the first optical output modulating means and the output of the second harmonic generating means are added to the optical wavelength multiplexing means to perform optical wavelength multiplexing.

[For production]

In FIG. 1 (Part 1), a second harmonic generation means 900
At this point, the output of the second optical output modulating means 400 is inputted, and the optical wavelength is set to 172 and outputted.

Then, the output of the first optical output modulation means 300 and the output of the second harmonic generation means 900 are applied to the optical wavelength multiplexing means to perform optical wavelength multiplexing.

As a result, two wavelengths can be multiplexed using one light emitting element.

In the case of FIG. 1 (Part 2), the two output lights of one laser diode are divided into the first and second output lights without using the light distribution means 150 as in the case of FIG. This is the same as in the case of FIG. 1 (Part 1) above, except that the optical output modulating means 310 and 410 of No. 2 are added.

〔Example〕

FIG. 2 is a block diagram showing the configuration of an optical communication system according to an embodiment of the present invention.

FIG. 3 is a block diagram showing the configuration of an optical communication system according to an embodiment of the second invention.

FIG. 4 is a diagram explaining the operation of the SHG crystal used in the example.

The same reference numerals refer to the same objects throughout the design.

The present invention differs from the conventional example in that 5econd t(ar
Using a monic generator crystal (hereinafter referred to as SHG crystal), two wavelengths, the original wavelength and the converted wavelength, are extracted from one light emitting element, modulated using an optical switch, etc., and wavelength multiplexed.

This will be explained in more detail below.

In the first embodiment of the first invention shown in FIG. 2 (part 1), the optical output of the LEDIO is added to the optical splitter 15 and is divided into two outputs with a wavelength λ (for example, 1.6 μm). The above outputs are respectively applied to known optical switches 35,45.

On the other hand, data ■ and ■ are added to the optical switch drive circuits 30 and 40, respectively, and the outputs drive the optical switches 35 and 4.
Turn 5 on/off.

For example, by connecting an SHG crystal 90 to the output of the optical switch 45, the second harmonic of the input frequency (
For example, optical signal data having a wavelength λ = 0.8 μm) is output. 31 (the output λ of the G crystal 90 and the output λ1 of the optical switch 35 are added to the WDM 50 to perform wavelength multiplexing, and the multiplexed output of λ1 and λ2 is sent to the optical fiber.

On the other hand, on the receiving side, the WDM 60 separates the input optical signal data into λ1 and λ2 data, and inputs them to the PIN diodes 70 and 80, respectively, to convert them into electrical signal data and receive the data.

Next, a second embodiment of the first invention will be described.

In Fig. 2 (part 2), the optical output of the LEDIO is added to the optical splitter 15 and the wavelength λ, (for example, 1.6 μm) is
into two outputs. One of the above outputs is applied to the optical switch 35, and the other is applied to the 5t (G crystal 91). As in the case of the first embodiment, data (2) is applied to the optical switch drive circuit 30, and the output causes the optical switch 35 to Turn on/off.

Further, the SHG crystal 91 outputs light of the second harmonic of the input frequency (for example, wavelength λ, =0.8 μm). Adding the optical output λ2 of this SHG crystal 91 to the optical distributor 16,
Branches into two optical outputs. The above two optical outputs are applied to optical switches 46 and 47, respectively, and are turned on and off by data 1 and 2 via optical switch drive circuits 42 and 43, respectively.

Then, the output of the optical switch 47 is applied to the SHG crystal 92, and as in the case of the SHG crystal 91 described above, light of the second harmonic of the input frequency (for example, wavelength λ, =0.4 μm) is output.

Output of the optical switch 35 (wavelength λ, = 1.0 μm),
The output of the optical switch 46 (wavelength λ2 = 0.8 μm) and the output of the SHG crystal 92 (wavelength λ3 = 0.4 μm) are −0.
In addition to M52, optical wavelength multiplexing of three wavelengths is performed.

On the receiving side, -DM 62 separates the multiplexed data of the wavelengths λ1, λ2, and λ3, and assigns each PIN.
In addition to the diodes 71, 72 and 73, the signal is converted into an electrical signal and received.

Next, an embodiment of the second invention will be described.

In FIG. 3, output light from both end faces of a laser diode (hereinafter referred to as LD) 11 (for example, wavelength
Add m)) to light switch 36.37. The following is the same as the case of the first embodiment (FIG. 2 (part 1)) of the first invention. In this case, by using LDII, high-power wavelength multiplexing can be performed, and an optical splitter is not required.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to realize an optical communication system with lower cost and lower power consumption.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the principle of the present invention. FIG. 2 is a block diagram showing the configuration of an optical communication system according to an embodiment of the invention. FIG. 3 is a block diagram showing the configuration of an optical communication system according to an embodiment of the second invention. 4 is a diagram explaining the operation of the SHG crystal used in the embodiment, and FIG. 5 is a block diagram showing the configuration of a conventional example. In the figure, 100 is a light emitting element, 110 is a laser diode, and 150 is a light emitting element.
is a light distribution means, 300.310 is a first light output modulation means, 400.41
0 indicates the second optical output modulation means, and 900.910 indicates the second harmonic generation means.

Claims (2)

[Claims] (1) Optical wavelength multiplexing means (500
), a light-emitting element (100) that emits light at a predetermined wavelength; a light distribution means (150) connected to the light-emitting element and distributing the light output of the light-emitting element; First and second optical output modulation means (300, 400) are connected to each other and perform predetermined modulation on the optical input using data; A second harmonic generation means (900) for outputting a 1/2 signal is provided, and the output of the first optical output modulation means and the output of the second harmonic generation means are added to the optical wavelength multiplexing means. , an optical communication system characterized by optical wavelength multiplexing. (2) Optical wavelength multiplexing means (510
), which emits light at a predetermined wavelength and has 2
a laser diode (110) having two output lights, and first and second optical output modulation means that input each of the two output lights of the laser diode and perform predetermined modulation on the optical input based on data. (310, 410), which is connected to the second optical output modulation means and which modulates the input optical wavelength by 1/
A second harmonic generation means (910) for outputting a second harmonic with a wavelength of An optical communication system characterized by wavelength multiplexing.