WO2015160073A1

WO2015160073A1 - Bidirectional communication optical transceiver

Info

Publication number: WO2015160073A1
Application number: PCT/KR2015/000219
Authority: WO
Inventors: 김동민
Original assignee: 김동민
Priority date: 2014-04-14
Filing date: 2015-01-09
Publication date: 2015-10-22

Abstract

An optical module device is disclosed. That is, an optical module device is formed in which two bidirectional integrated optical elements for transmitting and receiving optical signals by using two wavelength bands are integrated into one module, thereby forming a bidirectional communication optical module for simultaneously transmitting and receiving optical signals of four wavelength bands through one optical fiber, and thus provided is a bidirectional communication optical transceiver which simultaneously transmits four optical signals and simultaneously receives four optical signals through two optical fibers by integrating two bidirectional communication optical modules into one transceiver.

Description

Optical transceiver for bidirectional communication

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical communication module, and more particularly, to an optical transceiver for bidirectional communication, which performs transmission and reception through four wavelength bands, and performs two-way communication using four transmission wavelengths and four reception wavelengths using two optical fibers. will be.

In recent years, optical communication using light as a medium for information transmission has become common for high-capacity information transmission and high-speed information communication. Therefore, an optical signal can be easily converted into laser light using an optical transmission device, and conversely, optical reception device is used. Therefore, the optical signal transmitted through the optical fiber can be easily converted into an electrical signal.

Light has very low coherence with each other, and optical communication of two-way communication method that transmits and receives a signal through one optical fiber by using the characteristics of light is preferred.

As described above, in order to achieve the bidirectional optical communication, an optical receiving element that receives an optical signal transmitted downward through an optical fiber and converts it into an electrical signal and an optical transmission element that converts the electric signal into an optical signal and transmits the optical signal through the optical fiber are integrated. Therefore, there is a need for a bidirectional integrated optical device manufactured such that optical coupling with one optical fiber occurs.

In the case of such a bidirectional integrated optical device, it is common to perform bidirectional communication using optical signals of two wavelength bands. Thus, bidirectional communication using only optical signals of two wavelength bands is limited in communication capacity. .

Accordingly, in order to accommodate the increasing data traffic volume, wavelength band multiplexing is required to multiplex the wavelength band of an optical signal transmitted through one optical fiber. Thus, a bidirectional integrated optical device using only two existing wavelength bands is required. There is a need for new ways to use more than four wavelength bands.

In particular, in the data center where a large amount of information is transmitted and received through optical fibers, an optical module of a duplexer structure is used. The duplexer optical module performs two-way communication by using two optical fibers, and an optical element for transmission is optically coupled to one of the two optical fibers, and an optical element for reception is optically coupled to one of the two optical fibers and transmitted to one optical module. Receive bidirectional communication. However, the explosive amount of data information needs to make the communication more large. For this purpose, an optical communication module of a quadplexer small form factor pluggable (QSFP) method has been used. The optical communication optical module of QSFP (Quadplexer Small Form factor Pluggable) has four light emitting elements and four light receiving elements in one optical communication module, and uses a method of combining each optical element with each optical fiber. . In general, four light emitting devices can be manufactured in an array form so that the distance between the four light emitting devices can be set very densely, and four light receiving devices can also be manufactured in a single chip in an array form. Thus, the distance between the light receiving elements can be set very densely. However, since the light emitting device and the light receiving device have different structures from each other, it is impossible to manufacture a single chip, so an appropriate distance is required between the two types of devices. Therefore, the optical fiber connecting the QSFP typically uses a 12-core optical fiber, but a 12-core optical fiber is manufactured in a form in which four unused optical fibers are further attached between the optical fiber for the light emitting device and the optical fiber for the light receiving device.

1 shows a process of transmitting an optical signal in an optical fiber manufactured in such a form. However, the conventional QSFP uses four transmitting laser diode chips and four receiving photodiode chips, and there is a serious problem of wasting optical fibers because optical communication is performed by using each optical fiber to transmit or receive signals. .

[Preceding technical literature]

[Patent Documents]

(Patent Document 1) Patent Registration No. 10-1041570 (2011.06.08)

The present invention was created in view of the above circumstances, and an object of the present invention is to provide a bidirectional integrated bidirectional integrated optical module device that transmits and receives an optical signal using four wavelength bands in one bidirectional transceiver. By constructing a communication transceiver and connecting one optical fiber to a bidirectional integrated optical module device, the directional communication transceiver provides an optical transceiver for bidirectional communication that enables transmission and reception of optical signals in four wavelength bands simultaneously through two optical fibers. There is.

An optical module device according to a first aspect of the present invention for achieving the above object comprises: a first optical element for transmitting, receiving or simultaneously transmitting and receiving an optical signal based on a first optical axis; A second optical element configured to transmit, receive, or simultaneously transmit and receive an optical signal based on a second optical axis formed to be orthogonal to the first optical axis; And a wavelength selective filter for determining an optical signal transmission / reception path at an intersection point at which the first optical axis and the second optical axis intersect so that both the first optical element and the second optical element transmit and receive an optical signal through one optical fiber. Characterized in that it comprises a.

More specifically, the transmission and reception path of the optical signal is characterized by being determined by the transmission and reflection of the optical signal made by the wavelength selective filter.

More specifically, the optical signal transmitted and received through the one optical fiber includes a first wavelength band, and the second wavelength band having a difference by the predetermined wavelength band from the first wavelength band, the wavelength selective filter The optical signal transmitted and received by any one of the first optical device and the second optical device is transmitted, and the optical signal transmitted and received by the other is reflected to transmit and receive the optical signal of the first wavelength band in the first optical device. The second optical device may include a wavelength selective filter to transmit and receive an optical signal of the second wavelength band.

More specifically, each of the optical signals of the first wavelength band and the second wavelength band includes a reception wavelength band having a difference between the transmission wavelength band and the transmission wavelength band by a predetermined wavelength band, and the first optical band. Each of the device and the second optical device transmits an optical signal of the transmission wavelength band and receives an optical signal of the reception wavelength band.

More specifically, the wavelength selective filter includes an inclined surface having a predetermined inclination angle based on a vertical plane with respect to each of the first optical axis and the second optical axis at an intersection where the first optical axis and the second optical axis intersect each other. On the inclined surface, any one of the optical signal of the first wavelength band and the optical signal of the second wavelength band is reflected, and the remaining non-reflected optical signal is transmitted along the first optical axis or the second optical axis. It is characterized by.

In the second aspect of the present invention, by simultaneously embedding the two bidirectional integrated optical module devices in one transceiver device, two bidirectional communication optical module devices are provided in one bidirectional communication transceiver device, and each optical module device for bidirectional communication is provided. By combining one optical fiber, the optical transceiver for bidirectional communication transmits four different optical signals through two optical fibers and simultaneously receives four different optical signals.

According to the present invention, by integrating two bidirectional integrated optical modules that transmit and receive optical signals using four wavelength bands as one bidirectional transceiver, an optical signal of four wavelength bands can be efficiently transmitted through two optical fibers simultaneously. And simultaneously receive optical signals in four wavelength bands. This function is characterized in that the conventional QSFP optical module optically couples the light emitting elements to the four transmitting optical fibers and couples the receiving light receiving elements to the four receiving optical fibers in the four light emitting elements using only two optical fibers. The optical fiber is saved by transmitting the emitted signal and receiving the optical signal using four light receiving elements. This saving of fiber enables the use of the existing duplexer type fiber as it is, so it is very economical way to reduce the cost of replacing the fiber to increase the communication capacity.

1 is a view illustrating a state in which four transmission signals and four reception signals are transmitted through a 12-core optical fiber in a conventional QSFP optical communication method;

2 is a schematic block diagram of an optical communication system configured based on an optical module for bidirectional communication according to an embodiment of the present invention;

3 and 4 are views for explaining the transmission / reflectance according to the wavelength band of the light incident on the wavelength selective filter according to an embodiment of the present invention,

5 is a view for explaining a transmission loss according to a wavelength band in an optical fiber according to an embodiment of the present invention;

6 is a schematic structural diagram of an optical module device according to an embodiment of the present invention;

7 is a schematic structural diagram of a first optical device according to an embodiment of the present invention;

8 is a view for explaining the structure of a submount for mounting a wavelength selective filter according to an embodiment of the present invention;

9 and 10 are views for explaining the optical response according to the wavelength band in the optical receiving device (photodiode chip) according to an embodiment of the present invention,

FIG. 11 shows that two optical modules for bidirectional communication are integrated into one transceiver to transmit two wavelengths through each optical fiber and receive two wavelengths, thereby transmitting four optical signals to two optical fibers. And a view for explaining a function of receiving four optical signals simultaneously with two optical fibers,

12 is an optical device having a structure in which a laser diode chip emitting a first wavelength and a laser diode chip emitting a second wavelength are embedded in one optical device according to another embodiment of the present invention;

13 is an optical module for bidirectional communication including two laser diode chips in a first optical element and two photodiode chips in a second optical element;

14 is an optical module for bidirectional communication in which four laser diode chips are all disposed in one optical module, and four photodiodes are disposed in another optical module;

15 is an example of the external appearance of a conventional QSFP-type transceiver case,

16 is an example of the external appearance of the QSFP transceiver case in which the optical module for bidirectional communication according to an embodiment of the present invention,

17 is an example of a dual fiber collimator applied to the present invention,

18 is an example of an optical module for optical communication at four wavelengths using the dual optical fiber collimation apparatus of FIG. 17 and two optical devices for bidirectional communication;

FIG. 19 illustrates an example of a QSFP transceiver fabricated to mount two optical modules of FIG. 18 to one transceiver to transmit optical signals of four wavelengths and receive optical signals of four wavelengths.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

2 illustrates an optical communication system according to an embodiment of the present invention.

As shown in FIG. 2, an optical communication system according to an exemplary embodiment of the present invention receives an optical signal transmitted from a transmitting optical module device 1000 and an transmitting optical module device 1000. The optical module 3000 includes a receiving optical module device 2000 and an optical fiber 3000 which is a transmission medium for transmitting an optical signal between the transmitting optical module device 1000 and the receiving optical module device 1000.

The transmitter-side optical module device 1000 and the receiver-side optical module device 2000 both refer to bidirectional integrated optical devices having the same configuration capable of bidirectional communication. In such bidirectional integrated optical devices, transmission and reception of optical signals may be performed together. have.

Therefore, the transmitting side optical module apparatus 1000 may receive the optical signal transmitted through the optical fiber 3000 as well as transmit the optical signal through the optical fiber 3000. Similarly, in the receiving optical module apparatus 2000, In addition to receiving the optical signal transmitted through the optical fiber 3000, it is also possible to transmit the optical signal through the optical fiber 3000.

As described above, the transmitting side optical module apparatus 1000 and the receiving side optical module apparatus 2000 have the same configuration and operation characteristics. For convenience of description, only one transmitting side optical module apparatus 1000 will be described as an example. Let's do it.

The optical fiber 3000 refers to a multi-mode optical fiber that can be applied to both transmission and reception of an optical signal, and is not limited thereto, but also a single mode optical fiber capable of transmitting an optical signal. Applicable

On the other hand, according to an embodiment of the present invention, the optical module device 1000 transmits and receives an optical signal using four wavelength bands.

As such, in order to transmit and receive an optical signal using four wavelength bands, the optical module apparatus 1000 includes two optical transmitters (eg, semiconductor laser diode chips) for transmitting optical signals using two wavelength bands. In addition, two optical receiving elements (eg, photodiode chips) for receiving an optical signal input from an optical fiber must be arranged in one apparatus.

Here, in the case of a photodiode applied as a photoreceiving element, a transimpedance amplifier (TIA) and a capacitor for removing noise of an electrical signal input to the preamplifier are simultaneously used for the purpose of minimizing the noise of the signal. Often installed.

As such, in order to perform optical communication using four wavelength bands, two optical transmitters, two optical receivers, and two preamplifiers must be arranged in a single device, but the manufacturing difficulty and product characteristics according to the arrangement method. Will occur.

As a result, in order to optimize the difficulty of manufacturing the product and the change of product characteristics, a concrete plan for disposing two optical transmitters, two optical receivers, and two preamplifiers in the optical module device 1000 is required. will be.

On the other hand, as an optical fiber currently applied for short-range communication, it is common to use an optical fiber optimized for an optical signal of 850 nm wavelength band, for example.

In the optical signal of 1550nm wavelength band in such an optical fiber, the dispersion of the optical fiber is too large, which makes it difficult to transmit data.

Therefore, the wavelength band selected for short-range communication should be selected as the wavelength band as close as possible to 850 nm. However, in the short wavelength of 780 nm or less, optical loss is too large and optical communication is difficult. The difficult situation must be solved.

In such a situation, in order to increase the capacity of bidirectional communication using four wavelength bands, it is important to select and arrange wavelength bands that match the characteristics of the optical fiber.

In the case of a laser diode chip applied as an optical transmitting element in a bidirectional integrated optical device, laser light is emitted with a constant divergence angle around the laser diode optical axis.

Typically, if the divergence angle of the laser light emitted from the laser diode chip, and the radiating over respective (1 / e ²⁾ is 40 ° if the edge emitting type laser diode chipil, in the case of the surface emission type laser, the divergence angle ( 1 / e ² ) reaches about 16-30 degrees.

In this regard, referring to FIGS. 3 and 4, the transmission / reflectance according to the wavelength band of the light incident on the wavelength selective filter may be confirmed.

Here, the wavelength selective filter transmits or reflects the light emitted from the laser diode chip in the bidirectional integrated optical device to be transmitted to the optical fiber as an optical signal, or transmits or reflects the light transmitted downward from the optical fiber to be a photodiode as a light receiving device. Refers to a configuration required to transmit as an optical signal.

In the case of FIG. 3, the laser light incident on the wavelength selective filter disposed at 45 ° with respect to the optical axis of the laser diode chip has an angle of 30 °, 45 °, due to the divergent light characteristics of the laser light. When changing to 60 ° The transmission / reflection of the laser light is shown.

In addition, in the case of Figure 4, when the incident angle to the wavelength selective filter changes to 40 °, 45 °, 50 ° The transmission / reflection of the laser light is shown.

First, as can be seen from FIG. 3, when the divergence angle of the laser diode chip is +/- 15 ° about the optical axis, the transmission wavelength band of the wavelength selective filter is changed by about 150 nm.

On the other hand, in FIG. 4, it can be seen that the transmission wavelength band of the wavelength selective filter changes by about 60 nm when the divergence angle is +/- 5 ° about the optical axis.

As described above, since the transmission / reflection wavelength band of the wavelength selective filter varies depending on the incident angle of the wavelength selective filter, in order to perform optical communication using the four wavelength bands, very precise wavelength distribution of four wavelength bands is required. something to do.

In addition, in order to distribute the four wavelength bands, transmission loss according to the wavelength band in the optical fiber and the like must be further considered.

Referring to FIG. 5, transmission loss according to a wavelength band in a general multi-mode optical fiber can be confirmed.

Here, it can be seen that the 850 nm wavelength band has a loss rate of 2.2 dB / Km, and the 780 nm wavelength band has a loss ratio of about 1 dB / Km compared to 850 nm at 3.2 dB / Km in the 780 nm wavelength band.

However, in the 700nm wavelength band, the loss rate increases rapidly to 5.5dB / Km. Therefore, optical communication is mostly using 780nm or 850nm wavelength even for short distance communication.

In addition, in the case of the optical fiber having the best optical transmission characteristics at 780nm or 850nm, which is widely used in the past, the longer the wavelength of light passing through the optical fiber, the worse the optical communication quality due to modal dispersion in the optical fiber. There is a characteristic.

As such, since transmission loss in the optical fiber has a great influence on the optical communication quality, in order to perform smooth optical communication using the four wavelength bands, in addition to the divergence angle emitted from the aforementioned laser diode chip, the optical fiber transmission It can be seen that the loss characteristics and dispersion characteristics in the optical fiber according to the wavelength band should be considered.

Thus, in one embodiment of the present invention, using a two-way integrated optical device to propose a specific configuration of an optical module device for transmitting and receiving optical signals of four wavelength bands simultaneously through one optical fiber, and in the following This will be described.

6 is a view showing an optical module device according to an embodiment of the present invention.

As shown in FIG. 6, the optical module apparatus 1000 according to an exemplary embodiment of the present invention uses the first optical device 100 and the second wavelength band to transmit and receive an optical signal using the first wavelength band. The second optical device 200 for transmitting and receiving the optical signal and the optical signal is transmitted and reflected so that both the first optical device 100 and the second optical device 200 transmit and receive the optical signal through one optical fiber 3000. It has a configuration including a wavelength selective filter 300.

Here, the first wavelength band used for transmitting and receiving optical signals in the first optical device 100 includes a first transmission wavelength band λ1 and a first reception wavelength band λ2, and the second optical device 200 In the second wavelength band used for transmitting and receiving the optical signal in the ()) includes a second transmission wavelength band (λ3) and the second receiving wavelength band (λ4).

The first wavelength band and the second wavelength band mean different wavelength bands. On the contrary, the first wavelength band and the second wavelength band may use the second wavelength band in the first optical device 100, and the first wavelength band in the second optical device 200. Can also be used.

Similarly, the first transmission wavelength band [lambda] 1, the first reception wavelength band [lambda] 2, and the second transmission wavelength band [lambda] 3 and the second reception wavelength band [lambda] 4 also mean different wavelength bands. Of course, the wavelength band is not limited to the dedicated wavelength band for transmitting or receiving the optical signal, but may be changed according to designation.

The first optical device 100 transmits an optical signal using the first transmission wavelength band λ1 based on the first optical axis a for transmitting and receiving the optical signal, and the first reception wavelength band λ2. Receive an optical signal by using.

Here, the first optical axis a refers to a reference line for emitting laser light corresponding to an optical signal in a laser diode chip applied as an optical transmitter in the first optical device 100.

In addition, the second optical device 200 transmits the optical signal using the second transmission wavelength band λ3 based on the second optical axis b for transmitting and receiving the optical signal, and the first reception wavelength band λ3. ) To receive the optical signal.

Similarly, the second optical axis b refers to a reference line for emitting laser light corresponding to an optical signal in a laser diode chip applied as an optical transmitter in the second optical device 200.

In addition, the wavelength selective filter 300 transmits and reflects an optical signal at an intersection point at which the first optical axis a and the second optical axis b intersect each other, whereby the first optical device 100 and the second optical device 200. All transmit and receive optical signals through one optical fiber 3000.

More specifically, the wavelength selective filter 300 transmits the optical signal of the first wavelength band as it is to transmit and receive the optical signal of the first wavelength band in the first optical device 100, while the optical signal of the second wavelength band By reflecting, the second optical device 200 can transmit and receive the optical signal of the second wavelength band.

To this end, the wavelength selective filter 300 is based on the perpendicular to each of the first optical axis (a) and the second optical axis (b) at the intersection of the first optical axis (a) and the second optical axis (b). °An inclined surface having an inclination angle of?Will be reflected.

The transmission and reflection of the wavelength selective filter 300 may be performed by alternately depositing a dielectric film having a relatively high and low refractive index into a plurality of layers to transmit or reflect only an optical signal having a desired wavelength band.

For example, when the optical signal of the first transmission wavelength band λ1 transmitted from the first optical element 100 is incident on the inclined surface, the wavelength selective filter 300 receives the optical signal of the first transmission wavelength band λ1. As it is transmitted through the first optical axis (a) to be transmitted to the optical fiber 3000, as opposed to the wavelength selective filter when the optical signal of the first wavelength band λ2 transmitted from the optical fiber 3000 is incident on the inclined surface The reference numeral 300 transmits the optical signal of the first reception wavelength band λ 2 as it is, so that the optical signal may be transmitted to the first optical device 100 along the first optical axis a.

As another example, when the optical signal of the second transmission wavelength band λ3 transmitted from the second optical element 200 is incident on the inclined surface, the wavelength selective filter 300 receives the optical signal of the second transmission wavelength band λ3. 90 ° by tilting the second optical axis b from the inclined plane When the optical signal of the second receiving wavelength band λ4 transmitted from the optical fiber 3000 is incident on the inclined plane, the wavelength selective filter 300 may receive the second receiving wavelength. 90 ° through the slope of the optical signal in the band λ4 It can be transmitted to the second optical device 200 along the second optical axis (b).

Hereinafter, the configuration of the first optical device 100 and the second optical device 200 according to an embodiment of the present invention will be described in detail with reference to FIG. 7.

Here, in the case of the first optical device 100 and the second optical device 200, only the wavelength band used for transmitting and receiving the optical signal is different from the first wavelength band and the second wavelength band, as mentioned above. Since the other configurations and the operation characteristics according to the configuration are all the same, the following description will be made by using only the first optical device 100 as an example for convenience of description.

As shown in FIG. 7, the first optical device 100 according to an exemplary embodiment of the present invention drills through holes 105 in a substrate made of metal and inserts electrode pins 111 into the through holes 105. , A stem 110 made of a glass-sealed form, a metal cap 140 having elements disposed therein, sealed with a lens 150 or flat glass, and equipped with an optical opening through which laser light can pass. By having a structure that combines), it is easy to protect and internally use the internal element, and ensures airtightness.

In the first optical device 100, an optical transmitter 130 for transmitting an optical signal of the first transmission wavelength band lambda 1 and an optical receiver for receiving an optical signal of the first reception wavelength band lambda 2 transmitted from the optical fiber. The receiving element 170, the preamplifier 180 for amplifying the optical signal received by the optical receiving element 170, and the optical signal of the first transmission wavelength band [lambda] 1 are reflected and the first receiving wavelength band [lambda] 2. The optical signal of the wavelength selective filter 160 to be transmitted is mounted.

Here, as the optical transmitting device 130, for example, both an edge emiiting type laser diode chip and a surface emitting type laser diode chip (VCSEL) can be used, but considering characteristics suitable for near field communication Surface-emission laser diode chips that consume less electricity and have a narrower divergence angle of laser light are more appropriate.

In addition, the preamplifier 180 is the most heat generating element, it should be configured to be attached to the bottom surface of the stem 110 to facilitate heat release to the outside.

As such, configuring the layout such that the preamplifier 180 is attached to the bottom surface of the stem 110 may easily discharge heat from the preamplifier 180 to the outside to minimize the temperature rise inside the optical device, thereby increasing the temperature. This is to prevent deterioration of characteristics of the internal device.

For reference, reference numeral '131', which is not mentioned, is a submount on which the optical transmitter 130 is mounted, '171' is a submount on which the optical receiver 170 is mounted, and '120' is a wavelength selective filter ( 160) and the submount to be mounted.

The optical signal of the first transmission wavelength band λ1 emitted from the optical transmitting element 130 in the first optical element 100 having the configuration is output in parallel with the bottom surface of the stem 110 along the optical axis. This is reflected by the wavelength selective filter 160, and is transmitted to the optical fiber through the lens 150 on the wavelength selective filter 160.

The optical signal of the first receiving wavelength band λ2 transmitted from the optical fiber is converted into convergent light through the lens 150 and arrives. The wavelength selective filter 160 transmits the first receiving wavelength band λ2. The characteristic is set, so that the optical signal of the first receiving wavelength band λ2 is transmitted to the optical receiving element 170 through the wavelength selective filter 160.

The optical signal received by the optical receiving device 170 is amplified by the preamplifier 180 and transmitted to the outside as an electrical signal through the electrode pin 111.

Here, the wavelength selective filter 160 should be disposed to have an inclination angle of 45 ° with respect to the vertical plane of each of the optical axis of the optical transmitter 130 and the optical axis of the optical receiver 171.

The wavelength selective filter 160 may be modified in various ways, but in one embodiment of the present invention, the wavelength selective filter 160 is attached to the inclined surface of the wedge submount using the wedge-shaped submount 120. How to do it.

In this case, the wedge-shaped submount 120 should be made of a material having a thermal conductivity of 100 W / m / K, for example, in order to effectively dissipate heat generated from a laser diode chip. In particular, the wedge submount 120 has a very high thermal conductivity of 170 W / m / K. It should be made based on silicon having good processability.

In the case of the wedge-shaped submount 120, as an example of a method for securing a 45 ° inclination angle of the wavelength selective filter 160, as shown in FIG. 8, the inclination of the submount in which the inclination groove of the 45 ° angle is formed is shown. It is also possible to insert the wavelength selective filter 160 into the groove.

On the other hand, in the case of the optical transmission device 130 applied to the first optical device 100, typically has a divergence angle (1 / e ² ) of 16 to 30 °, with respect to the divergence angle of the wavelength selective filter 160 In the case of the transmission and reflection wavelength bands, a wavelength band shift of about 150 nm is made as described with reference to FIG. 2.

Therefore, in one embodiment of the present invention, the first transmission wavelength band [lambda] 1 and the first reception wavelength band [lambda] 2 must have a wavelength band difference of 150 nm or more from each other, and similarly, the second transmission wavelength band [lambda] 3 and The two reception wavelength bands λ4 should also have a difference in wavelength band of 150 nm or more.

In addition, the light emitted from the optical transmitting element 130 at the divergence angle 1 / e ² of 16 to 30 ° is converged by the lens 150.

At this time, the convergence angle varies depending on the magnification of the lens 150, but it is generally preferable to have the same convergence angle as the divergence angle of the laser light emitted from the optical fiber 3000, and thus, light converged by the lens 150. The convergence angle 1 / e ² of may have a value of +/− 5 °, for example.

Here, in the case of the transmission and reflection wavelength band in the wavelength selective filter 300 of FIG. 5 with respect to the divergence angle converged through the lens 150 of the first optical device 100, approximately 40 nm similar to that mentioned in FIG. A degree of wavelength band shift is achieved.

Therefore, in the exemplary embodiment of the present invention, the wavelength band of 40 nm or more must be different between the first wavelength bands λ1 and λ2 and the second wavelength bands λ3 and λ4.

As a result, the wavelength band difference between each of the first transmission wavelength band lambda 1, the first reception wavelength band lambda 2, and the second transmission wavelength band lambda 3 and the second reception wavelength band lambda 4 is 150 nm or more. Since the wavelength bands λ1 and λ2 and the second wavelength bands λ3 and λ4 have a wavelength band difference of 40 nm or more, both the first wavelength bands λ1 and λ2 and the second wavelength bands λ3 and λ4 are to be disposed. The minimum wavelength bandwidth that can be is 340nm.

On the other hand, as described with reference to Figure 4, in the optical fiber, since the transmission loss of the optical fiber is very large for the laser light of the wavelength band shorter than 780nm, it should be avoided to perform optical communication using the wavelength band shorter than 780nm. .

Therefore, when the minimum wavelength bandwidth in which both of the first wavelength bands λ1 and λ2 and the second wavelength bands λ3 and λ4 can be disposed is 340 nm, the shortest wavelength band becomes 780 nm, and conversely, the longest wavelength band May have a wavelength band of 1120 nm.

However, the oscillation wavelength band of the laser diode chip applied as the optical transmission element in the first optical device 100 and the second optical device 200 depends on the material composition of the active region which is the light formation region of the laser diode chip. This material composition can be determined by the substrate used in the laser diode chip.

Here, 780nm, 850nm, and 980nm are implemented as a laser diode chip based on a GaAs substrate, and the longest oscillation wavelength band commercialized so far is about 1060nm in the GaAs series laser diode chip based on the GaAs substrate. .

Therefore, in the case of a laser diode chip with a wavelength band longer than 1060 nm, an InP substrate is made of a base material. Currently, the shortest wavelength band of the laser diode chips based on an InP substrate is about 1250 nm. Depending on the composition ratio of the active layer is responsible for the laser oscillation in the wavelength range of 1250nm ~ 1620nm.

Therefore, in one embodiment of the present invention, 780 nm, 930 nm, and the second transmission wavelength band [lambda] 3 and the second reception wavelength band [lambda] 4 as the first transmission wavelength band [lambda] 1 and the first reception wavelength band [lambda] 2, respectively. ) Is a wavelength band of 990 nm and 1250 nm.

The distribution of the wavelength bands includes the first transmission wavelength band lambda 1, the first reception wavelength band lambda 2, the second transmission wavelength band lambda 3, and the second reception wavelength band (described above with reference to FIGS. 2 to 4). λ4) The wavelength band difference of each wavelength is 150 nm or more, and the wavelength band difference between the first wavelength bands λ1 and λ2 and the second wavelength bands λ3 and λ4 is 60 nm or more, and the wavelength band is not shorter than 780 nm. The four wavelength bands satisfy all the conditions as close as possible.

When using two or more InP-based laser diode chips, one of the laser diode chips may have a wavelength band close to 850 nm as much as 1250 nm, while the other laser diode chip is 1410 nm or more and a wavelength band far from 850 nm. Since it is possible to deteriorate the optical transmission quality due to the dispersion of the optical fiber is inevitable.

On the other hand, when four types of laser diode chips using GaAs substrates are used, the width of the oscillation wavelength band of the laser diode chip is 780nm to 1060nm, which is only 280nm. I can't get crazy.

On the other hand, in the optical communication system according to an embodiment of the present invention, four wavelength bands laser diode chip and four wavelength bands using different wavelength bands for transmitting optical signals using four wavelength bands, Photodiode chips, which are four optical receiving elements using different wavelength bands for receiving optical signals, can be applied.

Therefore, as the four optical transmitters, three kinds of laser diode chips using GaAs as a substrate and one type of laser diode chips using InP as substrates can be implemented to satisfy all of the above-described conditions related to the wavelength band.

Oscillating wavelength bands of laser diode chips, which are widely used in the world, are 780 nm, 850 nm, 980 nm, 1060 nm, 1310 nm, and 1550 nm.

In order to use such a conventional commercialized laser diode chip, the most suitable wavelength band distribution is, for example, a first transmission wavelength band (λ1): 780 nm, a first reception wavelength band (λ2): 980 nm, and a second transmission wavelength band (λ3). ): 1060 nm, second receiving wavelength band (λ4): 1310 nm, or first transmitting wavelength band (λ1): 780 nm, first receiving wavelength band (λ2): 930 nm, second transmitting wavelength band (λ3): 990 nm It is also possible to make slight changes in the wavelength band, such as the second received wavelength band? 4: 1250nm.

Considering the slight loss, it is also possible to start the first transmission wavelength band lambda 1 at 750 nm, and when the second transmission wavelength band lambda 3 is set to 1060 nm, the first transmission wavelength band lambda 1 and the second transmission. The wavelength band difference between the wavelength band lambda 3 corresponds to 310 nm.

In consideration of the 310 nm wavelength band difference, when the wavelength band difference 150 nm or a slight loss required for the wavelength selective filter disposed inside the first optical device 100 and the second optical device 200 is considered, 130 nm or more must be ensured. The wavelength band difference between the first optical device 100 and the second optical device 200, that is, the wavelength band difference between the first reception wavelength band λ 2 and the second transmission wavelength band λ 3, must be guaranteed to be 40 nm or more. .

Therefore, in the case of the first wavelength band used in the first optical device 100, the wavelength band difference between 130 nm and 270 nm or less must be different, and the wavelength band in the first optical device 100 and the second optical device 200 is different. The difference should be set to 40 nm to 180 nm or less, and in the case of the second wavelength band used in the second optical device 200, the wavelength band on the longer wavelength side is preferably as short as 1200 nm to 1400 nm.

Referring to FIG. 9, the photoreactivity of the first optical device 100 and the second optical device 200 according to the wavelength band of the photodiode having GaAs applied as the photoreceiving device as the substrate may be confirmed.

Here, it can be seen that the photodiode chip based on GaAs responds appropriately to 780 nm to 870 nm, and the photoreactivity is very poor at 740 nm or less and 880 nm or more.

In addition, referring to FIG. 10, it is possible to confirm the optical reactivity according to the wavelength band of the photodiode having GaAs applied as the photoreceiving element in the first optical device 100 and the second optical device 200 as a substrate. .

Here, it can be seen that the photodiode chip having InP as a substrate has good photoreactivity at 950 nm to 1600 nm, and rapidly falls at 950 nm or less.

Therefore, the wavelength band in the 900 nm to 950 nm band is difficult to manufacture a suitable photodiode chip, so it is not preferable to use it in the optical communication using the four wavelength band.

As a result, the wavelength spacing required for the wavelength selective filter, the wavelength band distribution obtained from the laser diode chip based on InP and GaAs, the optical reactivity of the photodiode chip based on InP and GaAs, Considering the characteristics of transmission loss and dispersion in the optical fiber 300, the most preferable wavelength distribution is 730 nm to 880 nm for the first transmission

wavelength band lambda

1, 950 nm to 1000 nm for the first reception wavelength band lambda 2, and It is preferable that the second transmission wavelength band? 3 has a wavelength band of 1010 nm to 1080 nm, and the second reception wavelength band? 4 has a wavelength band of 1260 nm to 1400 nm.

In this wavelength band, it is most desirable to set wavelength bands of 780nm, 980nm, 1060nm, and 1310nm, which are commercially available laser diode chips, and each laser diode chip typically has a wavelength error of about +/- 20nm. In the first transmission wavelength band λ1 is 780nm +/- 20nm, the first reception wavelength band λ2 is 980nm +/- 20nm, the second transmission wavelength band λ3 is 1060nm +/- 20nm, and the second reception wavelength band λ4 ) Is expected to have the most preferable wavelength of 1310nm + / -20nm.

FIG. 11 illustrates a case in which two

optical modules

1000 and 2000 for bidirectional communication described above are combined into one transceiver and used as one product. Since there is no signal interference between signals using different optical fibers, the two bidirectional communication optical modules in one transceiver become completely independent optical modules. Therefore, four optical signals are transmitted using two optical fibers and four The optical signal can be simultaneously received. Since this configuration is exactly the same as the function implemented in the conventional QSFP optical transceiver, it is possible to replace the conventional QSFP, and furthermore, the two-core duplexer type optical fiber that already has 12 core optical fiber required in the conventional QSFP optical transceiver. The economic benefits are substantial by allowing them to be replaced by

As described above, an optical transceiver for bidirectional communication according to an embodiment of the present invention simultaneously embeds two

optical module devices

1000 and 2000 for bidirectional communication, and each

optical module device

1000 and 200 for bidirectional communication is provided. Since the optical communication using the four wavelength bands is made by tying the first optical device 100 and the second optical device 200 into one, the communication capacity can be increased.

In addition, in manufacturing one optical module device 1000 by combining the first optical device 100 and the second optical device 200 into one, the layout may be configured such that the optical axes of the bidirectional integrated optical devices are orthogonal to each other, thereby increasing the volume thereof. It is easy to be compatible with existing devices that are being minimized and commercialized.

In addition, in configuring the first optical device 100 and the second optical device 200, the pre-amplifier 180, which generates a lot of heat, is attached to the bottom surface of the stem 110 to facilitate heat dissipation to the outside. By constructing the layout, it is possible to minimize the temperature rise inside the optical device and to prevent deterioration of characteristics of the internal device due to the temperature rise.

Although the present invention has been described in detail with reference to preferred embodiments, the present invention is not limited to the above-described embodiments, and the technical field to which the present invention belongs without departing from the gist of the present invention as claimed in the following claims. Anyone skilled in the art will have the technical idea of the present invention to the extent that various modifications or changes are possible.

In particular, in the conventional QSFP, since the preamplifier is not disposed at a position adjacent to the photodiode chip, the preamplifier may be removed from the optical device in the present invention.

As such, when the preamplifier is removed, a device that generates a lot of heat in the first optical device or the second optical device having the TO can type is eliminated. In this case, the photodiode must be placed on the bottom of the optical device. It is unnecessary to attach the laser diode to one side of the upper part of the photodiode.

That is, it is possible to arrange two laser diode chips in the first optical element and two photo diodes in the second optical element. FIG. 12 shows the first optical device when the laser diode chip 190 emitting the first wavelength and the laser diode chip 191 emitting the second wavelength are arranged in the first optical device. In this case, the photodiode chip receiving the third wavelength and the photodiode chip receiving the fourth wavelength are disposed in the second optical element.

FIG. 13 illustrates an optical module device in which two laser diode chips are disposed on a first optical element and two optical diode chips are disposed on a second optical element to bundle the optical elements vertically. In the optical module manufactured in the form of FIG. 13, two wavelengths are transmitted and two wavelengths are received, thereby performing the function of the optical module shown in FIG. 6. 13 differs from the characteristics of the optical module of FIG. 6 in that

laser diode chips

190 and 191 or

photodiode chips

195 and 196 are disposed in each optical device. In the arrangement of FIG. 6, since the laser diode chip and the photodiode chip receiving the laser light emitted from the laser diode chip are simultaneously embedded in one optical device, the laser light emitted from the laser diode chip simultaneously embedded in the optical device is transferred to the optical device. At the same time, leakage into the built-in photodiode chip can cause noise in the photodiode chip. Therefore, as shown in FIG. 13, when two laser diode chips are disposed in one optical element, or when two photo diode chips are disposed in one optical element, the laser diode chip and the photo diode chip may be simultaneously placed in one optical element. The noise is reduced compared to the placement.

As described above with reference to FIG. 13, an optical module for four-wavelength optical communication by tying two optical devices having two laser diode chips in one optical device and two optical devices having two photo diodes in another optical device is described with reference to FIG. 13. It was. However, on the other hand, two laser diode chips are attached to one optical element of the optical module and two laser diode chips of different wavelengths are attached to the other optical element, so that four laser diode chips are provided in one optical module. In addition, a method of manufacturing a QSFP may be possible by attaching photodiodes corresponding to four wavelengths to another optical module. An example of an optical module manufactured in such a form is illustrated in FIG. 14. In this case, all four

laser diode chips

190, 191, 192, and 193 are disposed in one optical module, and four photodiodes are disposed in another optical module. In this arrangement, all of the electric lines for transmitting the electrical signal for the laser diode can be driven to one side, whereby the QSFP can be easily manufactured.

Figure 15 shows the appearance of a conventional QSFP-type transceiver case. In FIG. 15, a space corresponding to 16.45 mm in width is a space in which a laser diode chip driver IC or the like is disposed, and spaces in which an optical module is disposed are 10.9 mm and 13.65 mm in FIG. 15. However, when fabricating an optical module corresponding to four wavelengths by using an optical device including two laser diode chips or photo diode chips used in the present invention, the width of the optical module is at least 8.5 mm. Therefore, two optical modules of this specification cannot be arranged in parallel in the internal space of the QSFP.

This difficulty is to place the optical modules in different positions in the longitudinal direction of the QSFP transceiver without placing the optical modules in parallel as shown in Figure 16, at least one optical module to the receptacle (3300) and the optical fiber (3100) for optical coupling with the external optical fiber This can be solved by having a form of connection.

Meanwhile, the optical module for optical communication using the four wavelengths of FIGS. 13 and 14 may be implemented in other manners.

17 shows the appearance of a dual fiber collimator 4000 applied to another embodiment of the present invention. In FIG. 17,

reference numerals

3400 and 3450 denote optical fibers. The optical signal transmitted from the outside through the optical fiber 3400 is converted into parallel light through a refractive index lens (Grin lens) 3600 and is incident to the wavelength selective filter 3700. Among the light reaching the wavelength selective filter 3700, the component 3900 that passes through the wavelength selective filter 3700 escapes the dual optical fiber collimation device 4000 and is used for light reception. On the other hand, the laser light 3950 of the component reflected by the wavelength selective filter 3700 enters another optical fiber 3450 and proceeds through the optical fiber 3450. The dual optical fiber collimation apparatus 4000 having such a function is equally applied to the light traveling in the opposite direction.

FIG. 18 shows an optical module for optical communication at four wavelengths using the dual fiber collimating device 4000 and two bidirectional communication

optical devices

100 and 200. In FIG. 18, the optical wavelength utilized in the optical device 100 is disposed on an optical path passing through the optical wavelength selective filter of the dual optical fiber collimation device 4000, and the optical wavelength utilized in the optical device 200 is used in the wavelength selective filter. Disposed in optical coupling with the optical fiber on the reflected optical path.

The dual optical fiber collimation apparatus 4000 of FIG. 18 and two

optical devices

100 and 200, each of which corresponds to an optical signal having two wavelengths, are capable of processing four optical wavelengths with a very small size. Will have

FIG. 19 illustrates an optical module capable of responding to four optical wavelengths by combining a dual optical fiber collimation apparatus 4000 and two optical elements each corresponding to two optical signals, and manufacturing two optical modules manufactured in this manner. An example of a QSFP transceiver, which is mounted on one transceiver, transmits an optical signal of four wavelengths and receives an optical signal of four wavelengths.

In FIG. 19, a laser diode chip and a photo diode chip that transmit four wavelengths and receive four wavelengths may be arranged in various ways. That is, a method of disposing two laser diode chips in one optical device, two photo diode chips in one optical device, or one laser diode chip and one photo diode chip in one optical device. This is possible. The wavelength selective filter transmits or reflects light depending on the wavelength of the laser light irrespective of the laser light propagation direction. Therefore, as long as the semiconductor chip embedded in one optical element is a wavelength separated by the wavelength selective filter, Combinations can also be used. Also in the method of combining two optical elements into one optical module, a method of combining four laser diode chips into one optical module, a method of combining four photo diodes into one optical module, and two lasers It is possible to combine a diode chip and two photodiode chips into one optical module. In the method of combining two laser diode chips and two photodiode chips into one optical module, a method of separating the laser diode chip and the photodiode chip into an optical device and configuring the optical device in one optical device and the laser diode chip and one Various arrangements are possible, such as a method of embedding a photodiode chip simultaneously.

Meanwhile, although the method of using the refractive index variable lens 3600 is illustrated in the embodiment of the present invention, the refractive index variable lens 3600 and the wavelength selective filter 3700 may be replaced with a concave lens coated with the wavelength selective filter. It is possible. In this structure, the light reflected by the wavelength selective filter coated on the lens having the concave lens structure among the laser light emitted from one optical fiber 3400 is focused to another optical fiber 3450 by the concave lens shape. The dual optical fiber collimation lens 4000 performs a function.

As such, the present invention is not limited to the above-described embodiments and various modifications within the equivalent scope of the technical concept of the present invention and the claims to be described below by those skilled in the art to which the present invention pertains. And of course modifications can be made.

According to the present invention, two bidirectional integrated optical devices for transmitting and receiving optical signals using two wavelength bands are integrated to transmit and receive optical signals of four wavelength bands simultaneously through one optical fiber. Limiting the existing technology by implementing two as one transceiver, it functions as a QSFP that transmits four optical signals and receives four optical signals through only two core optical fibers, not the 12 core optical fibers required in the conventional QSFP. The invention is an industrially available invention because it is not only sufficient for the use of the related technology but also the possibility of marketing or operating the applied device as well as being practically obvious.

[Description of the code]

1000, 2000: optical module device

100: first optical element

105: glass seal for joining electrode pins to stem

110: stem base metal

111: stem electrode pin

120: wedge submount

130: laser diode chip

131: submount for laser diode

140: lid cap of the TO can package

150: Lens installed on the lid of TO can package

160: 45 degree wavelength selective filter

170: photodiode chip

171: submount for photodiode

180: preamplifier

190: laser diode chip having a first wavelength

191: laser diode chip having a second wavelength

192: laser diode chip having a third wavelength

193: laser diode chip having a fourth wavelength

195: photodiode chip receiving a third wavelength

196: photodiode chip receiving a fourth wavelength

200: second optical element

300, 3700: wavelength selective filter

3000, 3100, 3400, 3450: Fiber Optic

3300: receptacle for optical coupling with external optical fiber

3600: refractive index variable lens

3900, 3950: light path

Claims

A first optical element transmitting, receiving or simultaneously transmitting and receiving an optical signal based on the first optical axis,

A second optical element for transmitting, receiving or simultaneously transmitting and receiving an optical signal based on a second optical axis formed to be orthogonal to the first optical axis,

A wavelength selective filter for determining an optical signal transmission / reception path at an intersection point of the first optical axis and the second optical axis so that both the first optical element and the second optical element transmit and receive an optical signal through one optical fiber; Optical transceiver for bidirectional communication comprising a; optical module device provided.
A first optical element for transmitting, receiving, or simultaneously transmitting and receiving an optical signal having two wavelengths,

A second optical element for transmitting, receiving or simultaneously transmitting and receiving an optical signal having two wavelengths different from the optical signal wavelength of the first optical element,

The first optical element and the second optical element are connected by an optical fiber, the first optical element transmits and receives a signal with an optical fiber connected to the outside through a wavelength selective filter disposed on one side, the second optical element is the first optical element And an optical module device for transmitting and receiving a signal with an optical fiber connected to the outside through reflection by a wavelength selective filter disposed at one side of the ruler.
The method according to claim 1 or 2,

The two optical module devices are embedded in one transceiver, so that four optical signals can be transmitted through two optical fibers and four optical signals can be simultaneously received.
The method of claim 3, wherein

A laser diode chip emitting a first wavelength and a laser diode chip emitting a second wavelength are disposed in a first optical element of any one of the two optical module devices, and in the second optical element. A laser diode chip emitting a third wavelength and a laser diode chip emitting a fourth wavelength are provided.

A photodiode chip receiving a first wavelength and a photodiode chip receiving a second wavelength are disposed in a first optical element of another optical module device, and a third wavelength is received in the second optical element. An optical transceiver for bidirectional communication, comprising: a photodiode chip and a photodiode chip receiving a fourth wavelength.
The method of claim 3, wherein

A laser diode chip emitting a first wavelength and a laser diode chip emitting a second wavelength are disposed in a first optical element of any one of the two optical module devices, and in the second optical element. A photodiode chip receiving a third wavelength and a photodiode chip receiving a fourth wavelength are provided.

A photodiode chip receiving a first wavelength and a photodiode chip receiving a second wavelength are disposed in a first optical element of another optical module device, and a third wavelength is emitted in the second optical element. An optical transceiver for bidirectional communication, comprising: a laser diode chip and a laser diode chip emitting a fourth wavelength.
The method according to any one of claims 1 to 3,

In the first optical element, a laser diode chip emitting a first wavelength and a laser diode chip emitting a second wavelength are disposed.

And the photodiode chip receiving the third wavelength and the photodiode chip receiving the fourth wavelength are provided in the second optical element.
The method according to any one of claims 1 to 3,

In the first optical device, a laser diode chip emitting a first wavelength and a photodiode chip receiving a second wavelength are disposed.

And the second optical device comprises a laser diode chip emitting a third wavelength and a photodiode chip receiving a fourth wavelength.
The method according to any one of claims 1 to 3,

The transmission and reception path of the optical signal,

The optical transceiver for bidirectional communication, characterized in that determined by the transmission and reflection of the optical signal made by the wavelength selective filter.
The method of claim 8,

In the optical signal transmitted and received through the one optical fiber,

A first wavelength band and a second wavelength band having a difference by a predetermined wavelength band from the first wavelength band,

The wavelength selective filter,

The optical signal transmitted and received by any one of the first optical device and the second optical device is transmitted, and the optical signal transmitted and received by the other is reflected to allow the first optical device to transmit and receive the optical signal of the first wavelength band. And the second optical device transmits and receives an optical signal of the second wavelength band.
The method of claim 9,

Each of the optical signals of the first wavelength band and the second wavelength band includes two optical signal wavelengths having a difference by a predetermined wavelength.

And each of the first optical element and the second optical element transmits, simultaneously receives, or simultaneously transmits and receives optical signals of the two wavelengths.
The method according to claim 1 or 3,

The wavelength selective filter,

An inclined surface having a predetermined inclination angle based on a vertical plane with respect to each of the first optical axis and the second optical axis at an intersection point where the first optical axis and the second optical axis intersect,

On the inclined surface,

The optical transceiver of any one of the optical signal having a different wavelength band is reflected, and the remaining non-reflected optical signal is transmitted along the first optical axis or the second optical axis.
The method of claim 2 or 3,

The wavelength selective filter,

An inclined surface having a predetermined inclination angle from each optical axis at intersections where optical axes of optical signals transmitted and received through the first optical device and the second optical device cross each other,

On the inclined surface,

The optical transceiver of any one of the optical signal having a different wavelength band is reflected, and the remaining non-reflected optical signal is transmitted along the optical axis, the optical transceiver for bidirectional communication.
The method of claim 3, wherein

At least one optical module of the two optical module device is optical transceiver for bidirectional communication, characterized in that connected to the optical fiber through a receptacle for optical coupling with the external optical fiber.
The method according to any one of claims 1 to 3,

And a lens is disposed between the optical fiber and the wavelength selective filter disposed on one side of the first optical element.
The method of claim 14,

And said lens is a refractive index lens.
The method of claim 14,

The wavelength selective filter is an optical transceiver for bidirectional communication, characterized in that the coating on the lens.