CN102436072A

CN102436072A - Novel optical digital signal processing system

Info

Publication number: CN102436072A
Application number: CN2011104560437A
Authority: CN
Inventors: 朱明皓; 张耀辉
Original assignee: Suzhou Institute of Nano Tech and Nano Bionics of CAS
Current assignee: Suzhou Institute of Nano Tech and Nano Bionics of CAS
Priority date: 2011-12-30
Filing date: 2011-12-30
Publication date: 2012-05-02

Abstract

The invention discloses a novel optical digital signal processing system. The system mainly comprises a vertical cavity surface emitting laser (VCSEL), a polarization beam splitter (PBS), a multi-quantum-well spatial light modulator (SLM) and a high-speed complementary metal oxide semiconductor (CMOS) detector linear array. The system is characterized in that a submicro metal-semiconductor grating is arranged on the light emitting surface of the VCSEL; the linear polarization orientation of the laser output by the VCSEL is the same as the periodic orientation of the submicro metal-semiconductor grating; and the average vertical polarization suppression ratio of the laser output by the submicro metal-semiconductor grating is more than 17dB. Compared with the prior art, the system has the following remarkable advantages: not only is the optical system greatly simplified, but also the electronics systems related to the optical system are simplified and the design and implementation difficulties of the optical computers are substantially reduced.

Description

A kind of novel optical digital information processing system

Technical field

The present invention relates to a kind of photoelectricity computing machine, relate in particular to a kind of novel optical digital information processing system that forms that makes up based on vertical cavity surface emitting laser.

Background technology

Adopt vertical cavity surface emitting laser (VCSEL) point light source line array, GaAs/GaAlAs MQW spatial light modulator (SLM) and high-speed cmos detector lines array can realize high speed optical and row vector-matrix multiply-add operation; This compute mode can realize the basic function of digital signal processing (DSP) system of microelectronic integrated circuit chip, and arithmetic speed can reach thousands of times of dsp chip.The optical system that realizes this Optical Parallel vector-matrix multiply-add operation requires to have very high precision.At first, vertical cavity surface emitting laser will reach more than 8 as the output electrooptical modulation precision of light source, means that the modulation gray scale will reach 256 grades; And the opto-electronic conversion precision of the electrooptical modulation precision of GaAs/GaAlAs MQW spatial light modulator and high-speed cmos detector lines array will reach more than 8.Except above-mentioned three kinds of key elements (VCSEL linear array, SLM face array and high-speed cmos linear array) need satisfy the above-mentioned requirements, crosstalking between the optical system light path also need be eliminated as far as possible, especially will eliminate crosstalking that the reflection of system light path causes.

Utilize light beam spectroscope (PBS) to eliminate the method for crosstalking that causes of reflection and obtained widespread use in fields such as CD-ROM.When illumination is on the PBS face, the light generation transmission parallel with the PBS polarization direction, the light vertical with the PBS polarization direction reflects.According to these characteristics of PBS, utilize linearly polarized light to realize irreversible light path, crosstalk thereby eliminate between system light path.

Yet existing VCSEL light emitted is not desirable linearly polarized light, and its polarization state can change along with the duty difference of laser instrument, even also can change along with the time.It is unstable that the light of the uncertain PBS of making transmission of the polarization of VCSEL light source or reflection becomes.In order to address this problem, optical system has adopted two-way polarization light path to compensate.The index path of the Optical Parallel vector-matrix multiply-add operation in the optical digital signal disposal system that designs by this mode such as Fig. 1 are to shown in Figure 5: (only showed single source and single lens the figure from the light of VCSEL light source 100 outgoing; Whole line source and lens arra are not drawn) be expanded into the sectored light face through lens 101, this sectored light face is regulated the direction of propagation, back through cylindrical lens 102 and is incident to light beam spectroscope (PBS) 103 vertically upward.The polarization direction light generation transmission parallel in the VCSEL light source emergent ray with the polarization direction of PBS 103, the light vertical with the polarization direction of PBS 103 reflects, and remaining light is by cancellation.Become circularly polarized light behind the reflected light process quarter-wave plate 104_a, vertical irradiation is to spatial light modulator 105_a.Spatial light modulator 105_a and CMOS chip 106_a flip chip bonding are interconnected, can realize that each pixel reflectivity is independent adjustable.Circularly polarized light has changed 180 degree through the reflected phase will of spatial light modulator 105_a; Such as becoming left circularly polarized light by original right-circularly polarized light; Again through quarter-wave plate 104_a; Become with the parallel linearly polarized light in PBS 103 polarization directions and transmit PBS 103, through another cylindrical lens 107 transmissions through PBS 108 to detector array 109_a.PBS 108 is light beam spectroscopes identical with PBS 103 polarization directions, and emergent ray to the different detector array that is used for separated cylinder lens 107 is to avoid interference.Opposite, transmitted light is incident to spatial light modulator 105_b and interconnected CMOS chip 106_b and the generation reflection of flip chip bonding through quarter-wave plate 104_b.The same generation 180 degree phase shifts of reflected light; Become vertically again through quarter-wave plate 104_b rear polarizer direction, reflect at PBS 103 places, through cylindrical lens 107 to PBS 108 with PBS 103; Launch equally at PBS 108 places, 109_b gathers by detector array.Visible from Fig. 2 to Fig. 5, each electronic system all need be accomplished " synchronously " on the sequential in this system, so the timing control unit among Fig. 1 111 becomes particularly important, is responsible for the synchronous of two-way electronic system and light path.

It is thus clear that this scheme needs two-stage PBS antireflection crosstalk processing, two spatial light modulators and two cmos detector linear arrays.Each spatial light modulator and cmos detector linear array correspondence are handled the light with PBS polarization parallel or vertical direction respectively, and need follow-up electricity to handle the signal plus with two cmos detector linear arrays difference corresponding units.The opto-electronic conversion of the transmission of each link of this two paths of signals of system requirements---electric signal and digital-to-analog conversion, spatial light modulator, the transmission of light signal and calculating, the signal stack of detector---accomplish fully synchronously.This has improved the difficulty of electricity system and data storage processing system, in fact needs two cover electricity system and stores processor systems, has increased total system power consumption and cost, has also greatly increased the adjusting difficulty of imaging optical system simultaneously.

Summary of the invention

For overcoming the deficiency of above-mentioned existing optical computational system; The object of the present invention is to provide a kind of novel optical digital information processing system,, improve computational accuracy with simplied system structure; Can satisfy the multi-grey level computing, reduce processing, assembling and the debugging difficulty of this system simultaneously.

Above-mentioned purpose of the present invention; Can realize through following technical scheme: a kind of novel optical digital information processing system; Mainly comprise vertical cavity surface emitting laser, light beam spectroscope, MQW spatial light modulator and high-speed cmos detector lines array; It is characterized in that: the light emitting surface of said vertical cavity surface emitting laser is provided with sub-micron metal-semiconductor grating; The linear polarization of wherein said vertical cavity surface emitting laser output laser is identical with the cycle direction of sub-micron metal-semiconductor grating, and through the average vertical polarization rejection ratio of the output laser of sub-micron metal-semiconductor grating greater than 17dB.

Further, be provided with and export the laser polarizer in the same way between said vertical cavity surface emitting laser and the light beam spectroscope, said polarizer gain vertical polarization rejection ratio is to more than the 25dB.

Technical scheme of the present invention compares to prior art, and its remarkable advantage is presented as: this system has not only simplified optical system greatly, and has simplified relevant with it electronic system.Specifically do not need two systems such as storage and the signal Synchronization between the SLM chip for driving, do not need yet between two cmos detectors reading synchronously and intensity addition is handled, the design that has significantly reduced optical computer with realize difficulty.

Description of drawings

Fig. 1 is the configuration diagram of prior art optical digital signal disposal system;

Fig. 2 is labeled as 2 electricity structure block diagram among Fig. 1;

Fig. 3 is labeled as 3 electricity structure block diagram among Fig. 1;

Fig. 4 is labeled as 4 electricity structure block diagram among Fig. 1;

Fig. 5 is labeled as 5 electricity structure block diagram among Fig. 1;

Fig. 6 is the VCSEL light-source structure synoptic diagram that the present invention has sub-micron metal-semiconductor grating;

Fig. 7 is the sized structural representation of sub-micron metal of the present invention-semiconductor grating;

Fig. 8 is the optical digital signal disposal system of the present invention output laser rays polarization direction light path synoptic diagram vertical with PBS;

Fig. 9 is the optical digital signal disposal system of the present invention output laser rays polarization direction light path synoptic diagram parallel with PBS.

Embodiment

Following constipation closes accompanying drawing, the innovation essence of technical scheme of the present invention is done further to specify, so that its easy to understand.

For the application that makes optical computer is further deepened; The polarization stability that solves the VCSEL light source is asked; The present invention innovates the technology imagination that has proposed a kind of novel optical digital information processing system; System architecture to simplify improves computational accuracy, can satisfy the multi-grey level computing, reduces processing, assembling and the debugging difficulty of this system simultaneously.Solution is to start with from the output laser polarization characteristic of VCSEL light source; The light emitting surface of existing VCSEL is added the linear polarization locking that sub-micron metal-semiconductor grating (as shown in the figure 2 and Fig. 3) is realized VCSEL output light characteristic, make VCSEL output polarisation of light direction not change with output intensity in time.The linear polarization of VCSEL output laser is identical with the cycle direction of metal-semiconductor grating.Adopt the average vertical polarization rejection ratio of the VCSEL array of this method manufacturing to surpass 17dB (power ratio that is two vertical polarization directions of emergent light is greater than 50 times), and the linearity of emergent light is good, the available current modulation.In order further to suppress vertical polarization, behind the VCSEL array, insert the polarizer (with emergent light in the same way), make vertical rejection ratio surpass 25dB, satisfy the requirement of 256 grades of modulation gray scales.

Extremely shown in Figure 8 like Fig. 6: this kind novel optical digital information processing system; Mainly comprise vertical cavity surface emitting laser 100 ', light beam spectroscope 103, MQW spatial light modulator 106 and high-speed cmos detector lines array 109; The light emitting surface of this vertical cavity surface emitting laser is provided with sub-micron metal-semiconductor grating, and (Fig. 8, Fig. 9 are not shown; Its structure such as Fig. 6 and shown in Figure 7); Wherein the linear polarization of this vertical cavity surface emitting laser output laser is identical with the cycle direction of sub-micron metal-semiconductor grating, and through the average vertical polarization rejection ratio of the output laser of sub-micron metal-semiconductor grating greater than 17dB.

Technique scheme can also further be optimized for, and is provided with and exports the laser polarizer 110 in the same way between this vertical cavity surface emitting laser 100 and the light beam spectroscope 13, and this polarizer 110 has gain vertical polarization rejection ratio to the ability more than the 25dB.

As shown in Figure 8; Be the optical digital signal disposal system output laser rays polarization direction light path synoptic diagram vertical with PBS, visible from illustrating: from the light process polarizer 110, lens 101, cylindrical lens 102 that VCSEL sends, reflection is through quarter-wave plate 104 on 103; Shine on the SLM105; Modulation through SLM driving circuit 106 reflects, and is parallel with 103 after 104 rear polarizer directions, throws to detector array 109 through cylindrical lens 107 through 103.

As shown in Figure 9, for the optical digital signal disposal system output laser rays polarization direction light path synoptic diagram parallel, visible from illustrating: through the polarizer 110, lens 101, cylindrical lens 102 with PBS; Transmission is through 104 on 103; Shine on 105, reflect and pass 104, the polarization direction becomes vertical with 103; On 103, reflect, be transmitted through 109 via 107.Shown in Figure 1 visible from Fig. 8 and contrast shown in Figure 9, electronic system has obtained effective simplification.

More than, be intended to easy to understand technical scheme characteristic of the present invention, protection scope of the present invention is not constituted any limitation through the description of practical implementation example.All employing equivalents or equivalence are replaced and the technical scheme of formation, all drop within the patented claim right protection domain of the present invention.

Claims

1. novel optical digital information processing system; Mainly comprise vertical cavity surface emitting laser, light beam spectroscope, MQW spatial light modulator and high-speed cmos detector lines array; It is characterized in that: the light emitting surface of said vertical cavity surface emitting laser is provided with sub-micron metal-semiconductor grating; The linear polarization of wherein said vertical cavity surface emitting laser output laser is identical with the cycle direction of sub-micron metal-semiconductor grating, and through the average vertical polarization rejection ratio of the output laser of sub-micron metal-semiconductor grating greater than 17dB.

2. a kind of novel optical digital information processing system according to claim 1; It is characterized in that: be provided with and export the laser polarizer in the same way between said vertical cavity surface emitting laser and the light beam spectroscope, said polarizer gain vertical polarization rejection ratio is to more than the 25dB.