KR20030081294A - Alignment Structure of Parallely Arranged Optical Transceiver - Google Patents

Abstract

PURPOSE: An alignment structure of an optical transceiver arranged in parallel is provided to reduce accessing process time by accessing an array where a number of light sources and optical detectors are formed in parallel to the optical waveguide of the optical transceiver at one time. CONSTITUTION: An optical waveguide in an optical integrated circuit(1) transferring a light signal is arranged independently, and a WDM filter(2) is inserted into the optical waveguide. An optical fiber array(5) where optical fibers are fixed is constituted. And a laser diode(3) and a photo diode(4) acting as a light source of the optical transceiver and an optical detector are arranged in parallel in the optical integrated circuit.

Description

Alignment Structure of Parallel Transmitter Arranged Optical Transceiver

The optical transceiver used in the optical communication system receives the optical signal from the outside and outputs its own optical signal. Such an optical transceiver may be referred to as an essential element for bidirectional communication when configuring an optical communication system. In order to miniaturize an optical communication system using a method of manufacturing an optical transmitter, a hybrid integration method in which a laser diode and a photodiode, a photodiode for optical transmission and optical reception, are directly mounted on a planar optical integrated circuit board is applied. To make a connection between the laser diode and the photodiode with the optical waveguide of the optical integrated circuit, fabricate the optical integrated circuit, planarize the substrate, and then etch the mounting portion of the substrate with precise depth to flip the laser diode and the photodiode by flip chip bonding. The board must be mounted so that it can be connected to the optical waveguide. In particular, very fine alignment is required to achieve the connection between the laser diode and the optical waveguide. In this method, precise mechanical processing is essential for miniaturization of the optical transceiver.

In the present invention, unlike the conventional method of connecting the light source and the photodetector to the optical waveguide in the fabrication of the optical transceiver, a process required for connection by connecting an array in which a plurality of light sources and the photodetectors are formed in parallel to the optical waveguide of the optical transceiver at once I want to reduce it in time.

1: Optical transceivers arranged in parallel configured according to an embodiment of the present invention

2a to 2d: manufacturing process diagram of an optical transceiver using a conventional optical integrated circuit

3 is an optical integrated circuit arranged in parallel configured according to an embodiment of the present invention

4: Light source array arranged in parallel constructed in accordance with one preferred embodiment of the present invention

5: Photodetecting array arranged in parallel configured according to a preferred embodiment of the present invention

6 is a process of aligning a light source array, a light detection array and an optical fiber array arranged in parallel with the optical integrated circuit arranged in parallel according to an embodiment of the present invention

Explanation of symbols for the main parts of the drawings

1: Optical integrated circuit arranged in parallel

2: WDM filter

3: array of light sources (laser diodes) arranged in parallel

4: photodetector (photodiode) arrays arranged in parallel

5: fiber arrays arranged in parallel

6: optical fiber

7: optical waveguide in optical integrated circuit

8: optical integrated circuit

9: Etched part where light source and photodetector are mounted

10: light source

11: photodetector

12: optical fiber array

1 is a representative view showing the contents to be achieved in the present invention. Instead of the conventional method of mounting a laser diode and a photodiode on a substrate as individual units to fabricate an optical transceiver, a plurality of laser diodes 3 arranged in parallel and a plurality of photodiodes 4 arranged in parallel are also provided. The optical fiber arrays 5 arranged in parallel are arranged and connected to the substrates of the plurality of optical integrated circuits 1 prepared and arranged in parallel, and connected to the input and output terminals of the optical waveguide 7. In the above description, the state arranged in parallel refers to a case in which an optical signal input or output to each individual element has no direct relation on a function or signal flow with another individual element positioned on the same substrate.

2A to 2D show a process of a method of manufacturing a conventional optical transceiver module. In order to form the optical waveguide 7 which serves to transmit the optical signal in the optical transceiver, after forming the cladding layer on the substrate, the core layer is again formed on the cladding layer. The core layer is then etched to form a core with an optical waveguide that performs a desired function. After the core is formed, the upper cladding layer is again formed and the top of the substrate is flattened. The necessity of the flattening process is a necessary process for accurate alignment in the connection of the laser diode, which is a light source, and the optical waveguide. After inserting the WDM filter 2 and mounting the laser diode 10 as a light source and the photodetector 11 as a photodetector on a substrate, a portion of the optical integrated circuit 9 is formed at a constant depth by dry etching. Dig into. The depth should be adjusted so that the center of the optical waveguide to which the optical signal is incident coincides with the center of the light source when the laser diode 10 as a light source is mounted. After the laser diode 10 and the photodetector 11 are mounted on a substrate by a flip chip method, an optical fiber 12 is connected to an optical waveguide at an input terminal to fabricate an optical transmitter.

In the present invention, instead of the conventional method of directly mounting a laser diode and a photodiode when fabricating a conventional optical transceiver, a laser diode array (3) and a photodiode array (4) arranged in parallel, and an optical fiber array arranged in parallel (5) is aligned and attached to the optical integrated circuit (1) arranged in parallel to produce a plurality of optical transmitters.

The optical waveguide 7 used as the optical signal transmission path of the optical transmitter and receiver shown as an example in the present invention has a form of a 2X2 optical coupler having bidirectionality. Unlike the conventional method of manufacturing a light transmitter by mounting a light source and a photodetector on a single 2X2 optical coupler, in the present invention, a 2X2 optical coupler serving as an optical signal transmission is manufactured as an array 1 on the same substrate. 3 shows a 2 × 2 optocoupler array 1 arranged on the same substrate. In order to form the optical waveguide 7 which serves to transmit the optical signal in the optical transceiver, after forming the cladding layer on the substrate, the core layer is again formed on the cladding layer. The core layer is then etched to form a core with an optical waveguide that performs a desired function. After forming the core, the upper cladding layer is formed again. A WDM filter 2 for selectively passing a wavelength is inserted into the intermediate waveguide of the formed 2X2 optocoupler of FIG. In order to insert the WDM filter (2) using a dicing saw equipment to groove the substrate to the thickness of the WDM filter (2), then insert the WDM filter (2) with an adhesive having a refractive index that matches the refractive index of the optical waveguide Fix it. The inserted WDM filter 2 receives an optical signal having a wavelength required when the optical signal multiplexed by the wavelength inputted to the optical transmitter according to the present invention is input, and passes the optical signal in another wavelength range to reflect the optical signal again. It sends out a signal.

4 shows a light source array 3 consisting of a plurality of laser diodes arranged in parallel for use in the present invention. In the light source array 3, laser diodes in the communication wavelength band are arranged in a straight line in parallel at regular intervals. The spacing of the laser diodes 3 arranged in parallel coincides with the spacing of the optical waveguide 7 for laser diode input of the 2 × 2 optocoupler of FIG. 3. 5 shows a photodetector array 4 arranged in parallel. In the photodetector array 4, photodiodes for receiving the optical signal are arranged in a straight line in parallel at regular intervals. The spacing of the photodiodes 4 arranged in parallel coincides with the spacing of the optical waveguides 7 for photodiode output located in the 2X2 optocoupler of FIG. 3. The optical fiber array arranged in parallel on the same substrate arranged at the position corresponding to the 2x2 optocoupler array 1 arranged in parallel on the same substrate prepared in FIG. 3 and the input / output end waveguide 7 on one side of the optocoupler array 1 Prepare (5). In addition, in the other optical waveguide of the optocoupler array 1, as shown in Figs. 4 and 5, a light source array 3 and a photodetector array 4 arranged in parallel on the same substrate are prepared.

In order to manufacture an optical transmitter for wavelength multiplexing presented as an example in the present invention, first, the light source array 3 arranged in parallel and the waveguide 7 of the corresponding 2X2 optical coupler 1 arranged in parallel The optical wave array 7 is aligned with the input and output waveguides 7 of the optocoupler 1 so as to align each other by an active alignment method. Finely align the optical fiber array 5 to the position where the output of the optical signal output from the light source array 3 is maximized, and attach it to the 2X2 optical coupler array 1 by using an adhesive or a fusion method. (3) is also attached with an adhesive to fix it. The photodetecting array 4 is attached behind the light source array 3 with the light source array attached to the 2X2 optocoupler 1. The substrates of the light source array 3 and the photodetection array 4 are gallium arsenide wafers based on potassium / arsenic components corresponding to Groups 3 and 5 of the semiconductor and have wavelengths of 1.3 um and 1.5 um, which are wavelengths for optical communication. The optical signal shows high transmittance. Therefore, in the method of the present invention, the optical signal incident on the optical detection array 4 in the optical waveguide 7 corresponding to the optical detection array 4 of the optical coupler 1 is transmitted through the substrate of the light source array 3 Incident to the detection array 4. Since the value of the incident optical signal can be known as the current value output from the photodetector 4, the photodetector array 4 is connected to the 2X2 optical coupler 1 at the position where the current value of the photodetector 4 is maximum. Attach. When the photodetector array 4 is attached to the back of the light source array 2, a low dielectric constant material is inserted between the light source array 3 and the photodetector array 4 or fixed with an adhesive having a low dielectric constant to fix the light source array ( Reduce the reflection loss that can occur between 3) and photodetector array 4. 6 shows the above alignment process.

The function of the optical transmitter manufactured in the present invention is as follows. Of the 1.3um / 1.5um optical signals of wavelength multiplex incident on the optical transmitter, the optical signal of 1.3um wavelength passes through the WDM filter 2 and enters the photodetector 4 so that the photodetector 4 receives the optical signal. . At the same time, the incident optical signal of 1.5um wavelength is reflected by the WDM filter 2 and output to the other optical waveguide 7. The light source 3 embedded in the optical transceiver outputs an optical signal having a wavelength of 1.3 um, and an optical signal is output through the first incident optical waveguide 7. Through this process, the optical transceiver of the present invention receives an optical signal of 1.3 um wavelength, reflects and outputs an optical signal of 1.5 um wavelength, and transmits an optical signal of 1.3 um wavelength through a light source mounted in itself. A plurality of optical transmitters manufactured by the method of the present invention can process both optical signals in a single mode state or optical signals in a multiple mode.

The optical transceivers arranged in parallel aligned and connected by the method of the present invention can be separated into an array element in which individual unit elements or a plurality of unit elements are combined so that each can be operated as a unit element.

In the conventional method of fabricating an optical transceiver using a planar optical integrated circuit, it is necessary to planarize the upper cladding. In addition, in order to mount the laser diode as the light source and the photodiode as the photodetector as individual units, the depth to be mounted at a predetermined position in the optical integrated circuit must be etched precisely so as to precisely connect the optical waveguide in the optical integrated circuit.

The method of the present invention does not require the planarization of the optical integrated circuit, unlike the conventional method of mounting the light source and the photodetector on the optical integrated circuit in the fabrication of the optical transmitter using the optical integrated circuit. Is connected to each other through a single alignment using an array formed in parallel and an optical fiber array arranged in parallel to produce a plurality of optical transceiver arrays, and dicing optical transceivers configured in parallel It is possible to drastically reduce the required process time, process manpower, and process equipment as compared to the conventional method by manufacturing a plurality of optical transmitters in one alignment process by separating them into individual units by the equipment such as saws.

Claims (6)

In manufacturing an optical transceiver using an optical integrated circuit, an optical waveguide in an optical integrated circuit serving as an optical signal is independently arranged in parallel, and a WDM filter is inserted into an independently arranged optical waveguide. An optical integrated circuit is constructed by arranging optical fiber arrays in which optical fibers are fixed at predetermined intervals in parallel to match the optical waveguides of the circuit, and a laser diode and a photodiode serving as a light source and a photodetector of the optical transceiver. Preparing a plurality of optical transmitters by arranging light source arrays and photodetecting arrays arranged in parallel so as to correspond to the intervals of optical waveguides in the array and aligning each other. The laser array of claim 1, wherein the light source arrays arranged in parallel are laser diodes outputting the same wavelength and are arranged at regular intervals, or lasers having different wavelength bands outputting optical signals having a constant wavelength interval for application to a wavelength multiplexing system. Characterized in that the diode is configured to coincide with the interval of the optical waveguide for carrying the optical signal transmission in the optical transceiver. The photodetector array of claim 1 arranged in parallel comprises a photodiode capable of receiving an optical signal having a wavelength of 1.3 um and a bandwidth of 1.5 um used as a communication wavelength and for transmitting optical signals within the optical transmission and reception. Characterized by being configured to match the spacing of optical waveguides to be performed The optical integrated circuits arranged in parallel, the light source arrays arranged in parallel, and the optical fiber arrays arranged in parallel with the photodetector arrays are aligned and fixed so that their center positions exactly coincide with each other. that The optical transceiver according to claim 1, wherein the optical transceiver can operate both a single mode optical signal and a multi mode optical signal used in an optical communication system. The method of claim 1, characterized in that the WDM filters inserted into the optical waveguides arranged in parallel are inserted at one time.