CN1170178C - Multi-channel Scalable Micromechanical Optical Switch Array - Google Patents

Abstract

A multi-channel expandable micromechanical optical switch array is characterized in that the optical switch array consists of a substrate (1), m×n micro-reflection units (2), a cover plate (3), m output quasi- A collimator (4), n input collimators (5), the micro-reflection unit (2) consists of a shaft (2a), a bearing (2b), a swing rod (2c), a micromirror (2d), and a coil (2e) , Permanent magnet (2f) composition. Compared with the existing technology, the outstanding advantages of the present invention are: high integration, small size, accurate and reliable optical path conversion, not limited by the wavelength of light waves, stable operation, fast switching speed, easy expansion into a multi-channel optical switch array, simple process, It is conducive to mass production, and is especially suitable for the switching and interconnection of optical signals in the all-optical network of the broadband high-speed and large-capacity integrated service digital network.

Description

Multi-channel Scalable Micromechanical Optical Switch Array

Technical field:

The invention relates to a coupling of optical waveguides, in particular to a multi-channel expandable micromechanical optical switch array.

Background technique:

With the rapid growth of global communication business volume, business forms are becoming increasingly diversified, image transmission and processing technology is developing day by day, and high-speed and large-capacity broadband integrated service digital network has become the development trend of modern optical communication networks. However, the switching and interconnection of optical signals in the optical fiber network is traditionally carried out by using the optical-electrical-optical method. This method has low speed, complex device structure, low reliability, and relatively large volume, which is far from meeting modern requirements. To meet the requirements of optical fiber communication technology, use the existing and to-be-laid optical fiber network to build a large-capacity all-optical network, realize optical-optical direct cross-connection, realize fiber-to-the-home, and comprehensively solve the information transmission caused by electronic processing intervening in optical switching. The bottleneck problem has become the key to the development of optical fiber communication technology. A very important reason restricting the development of all-optical networks is that fiber-to-the-home requires a large number of optical fiber communication devices, including optical switches, optical fiber connectors, optical fiber couplers, optical multiplexers, optical splitters, optical circulators and optical isolation Devices, etc., these devices are expensive, and it is difficult for users to adopt them in large quantities. Among them, the optical switch, especially the multi-channel optical switch, is one of the most used key components in the all-optical network.

In the all-optical network, the number of optical paths exchanged by a node is very large, and the all-optical cross-connect (O×C) is the key technology of the all-optical network, which plays a very important role, while (N×N) multi-channel optical The switch is the core device to realize all-optical cross-connection. Its function is to perform optical path conversion and realize optical signal exchange. The combination of optical switch and wavelength division multiplexer (Wavelength multiplexer/demultiplexer) becomes Optical Add/Drop Multiplexer which is widely used in urban ring.

Optical switches can be divided into two categories: one is a mechanical optical switch that uses electromagnets or stepping motors to drive optical fibers or optical components of appropriate shape, such as prisms or mirrors, to achieve optical path conversion. The other is a waveguide optical switch utilizing solid physical effects, such as electro-optic, magneto-optic, and acousto-optic effects.

Among various types of optical switches, the waveguide optical switch has a higher switching speed, and can achieve high-density integration by using microelectronics technology. However, it also has too much insertion loss and crosstalk, low extinction ratio, low power and heat generation The disadvantage of being too high, and the price is expensive, and the technology is immature, far from reaching the practical level. The mechanical optical switch technology is relatively mature, with small insertion loss, low crosstalk, stable and reliable technology, applicable to various types of optical fibers, and is widely used in existing optical communication networks.

Mechanical optical switches can be further divided into two categories, one is a prism or mirror driven by a relay or a stepping motor, the disadvantage is that the volume is larger, limited to 1×2, 2×2 and 1×n (n=8 , 16) type of optical switch, it is difficult to expand to m×n type, and the cost is high, and the process is relatively complicated. If multi-channel switching is required, cascading must be used, and the cost of equipment will rise sharply, so it can only be used for trunk optical Communication and some special occasions cannot be widely used in the fields of optical fiber access network and optical switching. The other type is micro-mechanical (MEMS), MEMS (micro-electro-mechanical system) is a micro-electro-mechanical system, which is inspired by the integrated circuit process and developed. In recent years, MEMS technology has been combined with optical technology on a large scale to produce micro-opto-mechanical systems (MOEMS). Optical switches developed with MOEMS technology are MEMS-type optical switches. The mainstream technology of this type of switch is generally to engrave moving or twisting miniature mirrors by deep reactive ion etching technology and surface micromachining technology, driven by electrostatic or thermal expansion. This type of switch has the advantages of compact structure, small insertion loss, excellent electrical and mechanical properties, low cost, suitable for mass production, relatively high integration, easy to expand into multi-channel switches, and will play an important role in future all-optical network communications. effect. However, the current technology is immature, and the process is complicated. It needs to use 50 layers of masks and etching processes. The process requirements are high, the positioning accuracy is difficult to control, and the yield is low.

Invention content:

The purpose of the present invention is to provide a multi-channel expandable micromechanical optical switch array with compact structure, low insertion loss, low crosstalk and easy batch manufacture.

A multi-channel expandable micromechanical optical switch array, characterized in that: the optical switch array consists of a substrate 1, m×n micro-reflection units 2, a cover plate 3, m output collimators 4, n Input collimators 5 are formed, wherein m×n micro-reflection units 2 are arranged on the substrate 1 in rows and columns, m×n grooves 1a are opened on the substrate 1, and the micro-reflection units 2 are composed of axes 2a, Composed of bearing 2b, pendulum 2c, micromirror 2d, coil 2e, and permanent magnet 2f, the shaft 2a with bearing 2b at both ends is arranged on the groove 1a, the bearing 2b is fixedly connected with the substrate 1, and the lower end of the pendulum 2c is fixed On the shaft 2a, the micromirror 2d is fixed on the upper end of the pendulum 2c, the coil 2e is fixed on the substrate 1, and the permanent magnet 2f is arranged on the top of the coil 2e; there are m×n micro-reflection units 2 on the cover plate 3 Through holes corresponding to the position, the cover plate 3 is fixed on the substrate 1, m output collimators 4 and n input collimators 5 are arranged on the cover plate 3, and the arrangement is in the output direction of the output collimator 4 It is 90° to the input direction of the input collimator 5, m and n are positive integers; the groove 1a is selected from one of a v-shaped groove, a trapezoidal groove, and a wedge-shaped groove, and the shaft 2a processed by micromachining is adopted. The length is 0.3-4mm, the diameter of the micro-machined bearing 2b is 0.5-2mm, the swing rod 2c is made of soft magnetic material, the mirror surface of the micromirror 2d is parallel to the movement direction of the swing rod 2c, and the cover plate 3 can be supported Or pads instead.

The working principle of the micro-reflection unit 2 is: when an electric pulse is connected to both ends of the coil 2e, the coil 1 will magnetize the swing rod 2c. Due to the resultant force of the two poles of 2f, the pendulum 2c stops at one end of a magnetic pole with a polarity different from its own. The direction of the electric pulse at both ends of the coil 1 determines the magnetization polarity of the pendulum 2c, and also determines the state of the micromirror 2d. The forward pulse keeps the micromirror 2d in the optical path, and the reverse pulse keeps the micromirror 2d out of the optical path. When the coil 2e is not energized, the swing rod 2c is attracted by the stopped magnetic pole, keeps the state unchanged, and realizes self-locking.

Fig. 3 is a kind of 1×2 micromechanical optical switch, which adopts a microreflection unit 2, the coil 2e is connected to the reverse pulse signal, and the micromirror 2d deviates from the optical path, so as to realize the work of the output collimator 4 and the input collimator 5′ connection; if the coil is connected to the positive pulse signal, the micromirror 2d is located in the optical path, and the output collimator 4 is connected to the input collimator 5 in operation.

FIG. 4 shows that the micromirror 2d leaves the optical path to realize the working connection between the output collimator 4 and the input collimator 5'.

FIG. 5 shows that the micromirror 2d is in the optical path, realizing the working connection between the output collimator 4 and the input collimator 5 .

FIG. 6 is a 4×4 micromechanical optical switch array, which adopts 16 micro-reflection units 2, 4 input collimators 5 and 4 output collimators 4, and has 16 working connection modes.

Compared with the prior art, the multi-channel scalable micromechanical optical switch array of the present invention has the following advantages:

1. Since the micro-reflection unit 2 of the present invention adopts the electromagnetic drive of the coil 2e instead of the relay or stepping motor drive used in the mechanical optical switch of the prior art, the landing area of the micro-reflection unit 2 is very small, only 7 ～12mm ² (3mm～4mm in diameter), the scalability of the optical switch of the present invention is greatly superior to that of the mechanical optical switch of the prior art, and N×N multi-channel optical switch matrix can be realized, and the volume is also smaller than that of the mechanical optical switch of the prior art. The switch is greatly reduced.

2. The optical path switching effect of the present invention is completed by the swing of the micromirror 2d driven by the pendulum 2c. It only requires the micromirror 2d to enter or leave the optical path. There is no requirement for the movement mode and distance, and it is easy to control.

3. The structure adopted by the present invention has good reproducibility, small stroke of the motion mechanism, and accurate positioning. Compared with the micromechanical optical switch of the prior art, the process is simple and is conducive to mass production.

4. The optical switch array of the present invention has a self-locking function compared with the micromechanical optical switch of the prior art, and only needs to utilize electric pulses to realize the conversion of the working state, and does not need to maintain its working state with a constant voltage, thus The device power can be reduced and the working stability can be improved. Prior art micromechanical optical switches, such as the patent CN2461012Y, require a constant voltage to maintain the working state, so the power is too high and heat is accumulated inside the device, which has a great impact on the working stability.

5. The optical switch of the present invention adopts a coil electromagnetic drive mechanism to realize low-voltage (≤5V) driving, which is much lower than that of the micromechanical optical switch of the prior art, whose driving voltage is as high as 100V.

6. The surface of the micromirror 4 in the present invention can be coated with a broadband high-reflection film. Compared with the interference type optical switch array in the prior art, there is no requirement for wavelength control, and it has broadband characteristics.

Description of drawings:

FIG. 1 is a schematic structural diagram of a multi-channel scalable micromechanical optical switch array of the present invention.

Fig. 2 is a sectional view along the line A-B of Fig. 1 .

FIG. 3 is a schematic structural diagram of the 1×2 micromechanical optical switch of the present invention.

Fig. 4 is a working state diagram of a 1×2 micromechanical optical switch.

FIG. 5 is another working state diagram of the 1×2 micromechanical optical switch.

FIG. 6 is a schematic diagram of a 4×4 micromechanical optical switch array.

Detailed ways:

A 4×4 micromechanical optical switch array, the structure of which is shown in FIG. 1 , FIG. 2 and FIG. 6 . 16 micro-reflection units 2 are used, and each unit has a diameter of 4mm. The material of the substrate 1 is aluminum alloy, and 4×4 V-shaped grooves on the substrate 1 are formed by electric discharge machining. The output collimator 4 and the input collimator 5 are fixed on the cover plate 3, the aperture of the through hole on the cover plate 3 is 4mm, the coil 2e is fixed on the base plate (1), the shaft 2 is made of cemented carbide, the length The diameter of the micromirror is 2.8mm, the diameter of the bearing is 1.1mm, and the thickness is 0.3mm. The micromirror 2d is a silicon wafer of 1.5×1.5mm, the mirror reflectivity is 99%, the impedance of the coil is 150 ohms, and the working pulse voltage is 5 volts. The relative positions of the micromirror 2d, the output collimator 4 and the input collimator 5 on the substrate are shown in FIG. 6 . The overall size of the optical switch array is 30×30×10mm, the switching time is less than 1ms, the maximum insertion loss is not more than 0.5dB, and the crosstalk is less than 50dB.

Claims (6)

1. extendible micromechanical optical switch array of multichannel, it is characterized in that: this array of photoswitch is by a substrate (1), m * n little reflector element (2), a cover plate (3), m output collimator (4), n input collimating apparatus (5) constitutes, wherein the individual little reflector element (2) of m * n is arranged on the substrate (1) in the mode of row and column, have m * n groove (1a) on the substrate (1), little reflector element (2) is by axle (2a), bearing (2b), fork (2c), micro mirror (2d), coil (2e), permanent magnet (2f) is formed, the axle (2a) that bearing (2b) is equipped with at two ends is arranged on the groove (1a), bearing (2b) is fixedlyed connected with substrate (1), the bottom of fork (2c) is fixed on the axle (2a), micro mirror (2d) is fixed on the upper end of fork (2c), coil (2e) is fixed on the substrate (1), and permanent magnet (2f) is arranged in the top of coil (2e); Have m * n and the corresponding through hole in little reflector element (2) position on the cover plate (3), cover plate (3) is fixed on the substrate (1), m output collimator (4) and n input collimating apparatus (5) are arranged on the cover plate (3), its arrangement is that the outbound course of output collimator (4) becomes 90 ° with the input direction of input collimating apparatus (5), and m and n are positive integer.

2. array of photoswitch according to claim 1 is characterized in that: described groove (1a) is selected a kind of in v type groove, ladder-type trough, the wedge-shaped slot for use.

3. array of photoswitch according to claim 1 is characterized in that: adopting its length of axle (2a) of micromachined is 0.3～4mm, and adopting its diameter of bearing (2b) of micromachined is 0.5～2mm.

4. array of photoswitch according to claim 1 is characterized in that: fork (2c) adopts soft magnetic material to make.

5. array of photoswitch according to claim 1 is characterized in that: the minute surface of micro mirror (2d) is parallel with the direction of motion of fork (2c).

6. array of photoswitch according to claim 1 is characterized in that: cover plate (3) can substitute with support or cushion block.

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