KR20110037428A - Wavelength detectable optical power meter - Google Patents

Abstract

PURPOSE: A wavelength-detectable optical powermeter is provided to enable easy maintenance and to increase reliability on measurement since there is no damage to a part and a clean state can be simply maintained by an air blower. CONSTITUTION: A wavelength-detectable optical powermeter comprises photo detector(13), an input port(14) and an optical signal wavelength. The photo detector and the input port are spatially arranged. The photo detector and the input port move a slider, into which a plurality of thin-film filters are inserted, to measure the wavelengths and intensities of a plurality of optical signals. The slider successively positions a plurality of filters through linear movement or rotating movement.

Description

Wavelength detectable optical power meter

The present invention relates to a structure and a manufacturing method of a wavelength sensing optical power meter capable of simultaneously measuring the wavelength and intensity of a standardized multi-wavelength optical signal used in an optical communication system.

In addition to the invention of optical fiber and the need for rapid large-capacity information exchange, optical communication technology has been developed, and the transmission speed of signals has developed from the gigabit (Gbps) era to the terabit (Tbps) era. The development of the optical communication technology has now become an environment in which optical communication can be performed even in homes, and the era of FTTH (Fiber-To-The-Home) is installed in each household using an optical communication transceiver module. Therefore, optical communication technology is now popularized so that even an optical module can be accessed even at home, and a passive optical network (PON) technology is introduced to provide a high quality communication means to a large number of subscribers at a low price.

In recent years, WDM (Wavelength Division Multiplexing) transmission, which transmits light of various wavelengths to one strand of optical fiber in consideration of economic efficiency, such as expansion of transmission capacity, has been in the spotlight, and GEPON (Gigabit Ethernet) in Korea and Japan. PON) is active and uses 1310nm and 1490nm light wavelengths to implement a system that sends and receives signals over a single fiber. In North America, Gigabit PON (GPON) technology is applied to add 1550nm wavelength to transmit and receive video signals such as CA TV (cable TV) along with existing digital data (1310nm, 1490nm) through a single fiber. Therefore, in order to manage the network and install and maintain the subscribers, it is necessary to measure and measure optical signals of various wavelengths. Portable wavelength sensing power meters have emerged.

Furthermore, the need to identify wavelengths has increased due to the use of more wavelengths for coarse wavelength division multiplexing (CWDM) communications, which are being developed to expand the volume and speed of data and meet security needs.

Conventional wavelength sensing (selective) power meters use multiple photodetectors (or photo diodes, PDs, or photo diodes) for each wavelength. It consists of an optical splitter, coupler, lens, and various types of filters, which not only complicate the device but also increase the size and maintenance of the device. It will be difficult to repair and lead to an increase in price.

Figure 1 shows a representative appearance of the optical module currently being used. A plurality of pins (2) for supplying an electrical signal to the optical module (1) is attached, and the optical fiber (3) is attached to transfer the electrical signal to the optical signal through the optical fiber line. At the end of the optical fiber, various shapes of optical connectors (FC-PC, SC-PC, ST, MU, ...) (4) are attached for smooth connection with the optical fiber line. Generally, the optical signal emitted through the optical connector ( The performance of the optical module is evaluated by measuring the characteristics of 5).

The type of optical fiber used in the optical communication line is typical of single mode optical fiber, and the diameter of the optical fiber core to which a signal is transmitted is extremely small, 10 micrometers, and the connection between such small optical fiber cores requires sophisticated mechanical coupling within 1 micrometer. do. For this purpose, a delicately designed adapter is used. The reliability of the measurement data can be greatly affected by very small dust or small scratches. Therefore, the coupling between the optical fiber and the optical fiber (or the optical connector and the optical connector) is an important task. do.

Figure 2a shows the configuration and operating principle of a representative device (US Patent US 7,187,861) currently commercialized as an optical power meter designed to measure the optical wavelength and optical power at the same time.

Referring to Fig. 2a, the operation principle is as follows. The mixed signal of S2 (1490 nm) and S3 (1550 nm) is input to adapter A through a 1: 9 splitter. At this time, the physical contact between the optical fiber is made between the splitter and the coupler via the adapter A. The optical signals S2 and S3 input through the adapter A are input to the splitter 20% through the 80:20 coupler (S2 'and S3'). The mixed light signals S2 'and S3' input to the splitter are divided into two branches in a 90:10 splitter, and are respectively input to the 1490 nm transmission filter and the 1550 nm transmission filter (S2 ", S3 "). Since only 1490nm filter passes S2 '' and only 1550nm filter passes S3 '', the signal passing through each filter detects the magnitude of the signal in the photo-detector and measures the input power for a specific wavelength.

In the case of the optical signal S1 of 1310 nm wavelength, it is input to another adapter B and finally passes through the 1310 nm transmission filter along a path different from S2 and S3, and is configured to measure the signal size.

In this case, the coupler is also composed of optical fibers, so the coupler, splitter, and multiple PD power measuring device is composed of optical fibers. It is inconvenient to use a connector (or an adapter) and to prevent contamination by wiping the optical connector and optical fiber end surfaces from time to time during use. Therefore, if the coupling of the connector is unstable, the measurement value for the optical power has a defect that can be significantly different from the actual. In addition, the power meter shown in FIG. 2A not only cannot measure wavelengths other than three but also has limitations in that there is no extensibility such as adding wavelengths. In addition, since the transmission paths for each wavelength are different, the two adapters are attached, so that only the user who knows the wavelength information can find and measure an appropriate adapter, which is inconvenient for the measurement. .

As another example, in the case of using an optical wavelength filter generally manufactured as a part as shown in FIG. 2b, not only a large number of PDs are required for each wavelength, but also an expensive optical fiber attached optical wavelength filter must be configured according to the number of wavelengths. It is difficult to lower prices. The function of CWDM filter1, which is an internal core component, transmits only the desired wavelength (S1) when the optical signals (S1, S2, ..., Sn) with different wavelengths are inputted, and reflects the remaining wavelength signals to other output stages. It is an expensive component manufactured using three optical fibers, expensive lenses, and filters. Therefore, in order to separate multiple wavelengths as shown in the figure, CWDM filters should be used as many wavelengths and photo-detectors should be attached to each stage. Therefore, the cost is not only expensive but also bulky.

In addition, there is a problem in that the device is complicated because each component must be configured by connecting optical fibers in the packaging. In the case of this type of optical power meter, since the optical fiber attached to the optical filter and the optical fiber of the measurement sample (optical module) need to be optically coupled, a sophisticated connector must be used as in the case of FIG. Difficult to manage

In the case of FIG. 3A, a CWDM filter is arranged in a free space in a zigzag to extract a desired wavelength from an input optical signal in the middle to measure wavelength and intensity with a photo-detector (Korea Patent 10-0786341). In this case, since the optical fiber of the optical module to be measured has no direct contact with the filter, there is an advantage in the maintenance of foreign substances, but the manufacturing cost increases at the same rate because the number of photo-detectors is required as the number of measurement wavelengths, and the number of channels increases. As a result, there is a technical difficulty in accurately aligning each part, which shows that there is a limit in actual production.

FIG. 3b shows a representative view of the PCT invention (WO 2009/084761 A1) designed to improve the disadvantages of a power meter that requires multiple photodetectors as described above. However, in this case as well, in order to send an optical signal to the input unit (collimate or focusing unit) 8 connected with the optical fibers 6 and 7, as well as the contact between the optical fibers and the optical fibers, it is necessary to use sophisticated connectors and clean maintenance. It has the disadvantage of being difficult. In addition, in the case of FIG. 3B, since the rotating plate 9 with the filter is positioned perpendicular to the light propagation direction, the size of the optical filter having a size of several mm may be increased in the vertical direction. There is a difficulty in making the meter.

As described above, the conventional optical power meter capable of measuring wavelengths includes various unreasonable points such as problems of maintenance, high cost of manufacturing, difficulty of manufacturing, and problem of increasing volume. It is an object of the present invention to provide a structure and a manufacturing method of a wavelength sensing optical power meter that can be configured to detect power at the same time, but are simple to manufacture, low cost, and easy to maintain and use, thereby increasing the reliability of the measured value.

The present invention devised to solve the various unreasonable points of the conventional optical power meter is based on a single photodetector and one input port based on the number of low-cost filters that are suitable for the purpose of the wavelength sensing type The present invention relates to the manufacture of an optical power meter, wherein the optical signals emitted from the optical connector inserted into the input port are spatially aligned in one photodetector (photodetector) having a large light receiving area, and a plurality of optical filters are inserted in a row The structure of the wavelength sensing optical power meter that can increase the reliability of the measured value by simple and inexpensive manufacturing and easy maintenance in use by inserting the slider to detect the desired wavelength and optical power simultaneously. Provide a manufacturing method

Conventional wavelength sensing (selective) power meters use multiple photodetectors (or photo diodes, PDs, or photo diodes) for each wavelength. In addition, expensive splitters, couplers, lenses, and various types of filters are added, which not only complicates the device, but also increases the size and maintenance of the device. Will cause an increase. In particular, the accuracy of the measured value may be impaired during the optical coupling between the optical fiber connector attached to the optical module to be measured and the optical fiber attached to the adapter of the power meter. This damage can cause inaccurate readings, which is a hassle to keep clean at all times.

However, in the case of the present invention, it is simple, inexpensive and easy to use by constructing a photodetector with a large light receiving area and a single input port based on a small sized low-cost filter inserted in a line according to the number of measurement wavelengths. Provides a wavelength-sensitive optical power meter that is easy to maintain. In particular, the photodetector, the filter, and the end of the optical fiber attached to the optical module to be measured are all spatially separated, so there is no damage to the component even when foreign substances such as dust enter, and it is easily cleaned by an air blower. It is easy to maintain and increases the reliability of the measured values.

The wavelength sensing optical power meter according to the present invention is a device capable of simultaneously measuring the wavelength and the optical power of an input optical signal, and will be described in detail with reference to the accompanying drawings.

4 shows the basic principle of the present invention and is configured to receive the optical signal 12 emitted from the connector 11 attached to the optical module to be measured by the photo detector 13 and measure the optical power. In order to add the function of measuring the optical wavelength, a slider 16 having various kinds of optical filters 15 that can move in the vertical direction 17 is inserted into the optical signal to transmit only a signal having a desired wavelength. Optionally, the optical power of a specific wavelength can be measured. At this time, the function of the receptacle 14 is a means for obtaining an accurate measurement value by always fixing the optical connector at a constant position. That is, when the optical port connector 11 of the optical module to be measured is inserted into the receptacle 14 and the photo detector 13 which are the input ports so that the central axis is aligned, the light receiving area of the photo detector 13 is the optical module. Configure to accept all signals from At this time, the receptacle 14 is made of a removable removable to accommodate a variety of optical fiber connectors (SC-PC, FC-PC, MU, ...).

FIG. 5 shows a stereoscopic view (FIG. 5A) and a top view (FIG. 5B) of a slider inserted in the middle. As shown in FIG. 5A, the optical filter 23 selected to fit the measurement wavelength is inserted into the groove 27 of the slider 21 processed so that a plurality of optical filters can be mounted and fixed with the filter cap 24.

The characteristics of some filters mounted on the slider are shown in FIG. 6, wherein FIG. 6A is a filter for transmitting an optical signal of 1310 nm wavelength. Each filter transmits a signal having a desired wavelength and blocks a signal having a wavelength other than that. It is coated and has a range of transmission band widths to sufficiently block adjacent wavelengths. Therefore, the closer the adjacent wavelength is, the more difficult it is to manufacture, since the transmission characteristics of the filter must be steep to reduce the crosstalk between channels in order to increase measurement accuracy. 6B is a characteristic graph of a filter which transmits another wavelength of 1490 nm. Thus, by arranging several filters having different characteristics, it is possible to have various wavelength selectivity.

In addition, between the receptacle and the filter, a free space lens may be inserted in some cases to collect optical signals emitted from the connector of the optical module to be measured to compensate for the filter characteristics and to increase the accuracy of the measured optical power. Can also be.

FIG. 7 is a front view of the receptacle 31, the slider 32, and the photo detector 33. As shown in the drawing, the switch 34 is mounted at the position where the slider 32 is in contact with the main body (bottom of the slider) to move the slider so that the specific switch is operated by the contact spring 36 as the position is changed. At this time, by detecting a signal passing through a filter that transmits a specific wavelength it operates to measure the wavelength and optical power at the same time. Therefore, when the slider 32 is moved so that the filter 6 is in front of the photodetector 33, the switch 6 is operated so that the optical signal having the characteristics of the filter 6 can be seen when the optical signal is detected here. It is. In this way, when the light is moved to the position of filter 1, the wavelength detection signal is turned on at the position where the optical power is detected, and the wavelength and the optical power at this time are converted into a preset unit in the display 47.

In case of an optical signal that cannot pass through the filter, it is reflected from the filter. Since the reflected light acts as a noise in the signal entry through the filter, it must be thoroughly prevented from entering the photo detector through any path. The accuracy of the optical power meter can be secured. To this end, the gap between the photodetector and the slider is minimized and the reflected signal is absorbed and extinguished so that the inside is blackened to produce a light absorber.

In FIG. 7, when the power meter is manufactured in the form of the optical filter in the position of filter 6 of the slider, all the light may pass through, and thus it may be used as a master channel. That is, it can detect the optical signal of any wavelength that can be detected by the photodetector, so it can be manufactured to determine the presence or absence of the signal or to measure the power of the transmitted signal other than the filter wavelength installed in the power meter.

FIG. 8A shows three-dimensionally the components used for fabrication, and FIG. 8B shows three-dimensionally the wavelength-sensitive optical power meter completed by assembling the components of FIG. 8A. The touch pad 48 is mounted to set the condition and the status can be checked through the display window 47.

9 shows the concept of measuring the characteristics of the optical module 51 using a wavelength-sensitive optical power meter to which the present invention is applied.

When the shape of the slider is manufactured in a circular shape 63 rather than a linear shape as shown in FIG. 10, and then the filter 64 is disposed along the circumference, the slider can rotate to achieve the measurement effect as described above. (66) or a small motor can be configured as a simple wavelength-sensitive optical power meter that can be moved manually or automatically. In this case, the rotary slider sits in the horizontal direction of the power meter, providing a highly scalable configuration that can increase the number of measured wavelengths by increasing the number of filters without increasing the thickness of the power meter.

Although the exemplary embodiments of the present invention have been described above, various modifications can be made without departing from the scope of the present invention by those skilled in the art to which the present invention is applied. Therefore, the scope of the present invention should not be limited to the described embodiments, but should be defined by the ordinary ones as well as the claims described below.

1 is a basic structure of the optical module to be measured through the present invention

2A, 2B, 3A, and 3B are configuration diagrams of a conventional wavelength selective optical power meter.

4 is a configuration diagram of a wavelength sensing optical power meter to which the present invention is applied

5 is a three-dimensional and plan view of the slider which is a key component of the present invention;

6 is a characteristic graph of an optical wavelength filter according to the present invention.

7 is a front view of aligned key parts of the present invention;

Figure 8a, 8b is a component configuration and three-dimensional view of the wavelength-sensitive optical power meter completed with the present invention

9 is a conceptual diagram for measuring an optical module using a wavelength sensing optical power meter to which the present invention is applied

10A and 10B illustrate a wavelength sensing optical power meter equipped with a circular slider in a variation of the present invention.

1. Optical module 2. Pin for driving optical module

3. Fiber Optic 4. Optical Connector

5. Optical signal 6. Optical fiber

7. Fiber Optic 8. Collimator

9. Filter

11. Optical connector 12. Optical signal

13. Photodetector 14. Receptacle

15. Light wavelength filter 16. Slider

17. Direction the slider moves

21. Slider 22. Slider knob

23. Light wavelength filter 24. Filter cap

25. Contact spring 26. Inserted wavelength filter

27. Filter groove

31. Receptacle 32. Slider

33. Photodetector 34. Switch

35. Light wavelength filter 36. Contact spring

41. Optical Connectors 42. Receptacles

43. Switch 44. Photodetector

45. Slider 46. Control board

47. Display 48. Touchpad

49. Direction of Slider Movement

51. Optical Module 52. Fiber Optic

53. Optical signal 54. Amplification circuit

55. control IC circuit 56. control board

57. Touch Pad 58. Connection Circuit

61. Receptacle 62. Photodetector

63. Circular Slider 64. Optical Wavelength Filter

65. Direction of Circular Slider 66. Rotating Knob or Rotating Motor

67. Amplifier Circuit 68. Control IC Circuit

Claims (6)

Wavelength-sensing light designed to spatially arrange one photodetector and one input port (receptacle) and to measure the wavelength and intensity of multiple optical signals by moving sliders with multiple thin film filters in-line between them Power meter The apparatus of claim 1, wherein a plurality of switches are mounted at a place where the slider and the main body come into contact with each other to move the slider so that a specific switch operates as the position is changed, and passes through a filter manufactured to transmit a specific wavelength based on the position. Wavelength-sensing optical power meter, characterized in that to measure the wavelength and intensity at the same time by detecting the optical signal The wavelength sensing optical power meter according to claim 1, wherein the slider allows positioning of a plurality of filters in sequence through linear motion or rotational motion. The wavelength sensing optical power meter according to claim 1, wherein the input port attaches a receptacle that is detachable to accommodate various optical fiber connectors. The wavelength sensing optical power meter according to claim 1, wherein the slider to which the filter is attached consists of a removable filter using a filter cap so that the filter can be easily changed according to measurement requirements, thereby allowing for easy extension to the wavelength. According to claim 1, a part of the slider to which the filter is attached is manufactured without an optical filter, so that it can be used as a master channel through which all light can pass, so that optical signals of any wavelength can be detected. Wavelength-sensing optical power meter that makes it possible to determine, or to measure the power of transmitted signals other than the filter wavelength mounted on the power meter.

Images