Chế tạo máy đo xa laer, an toàn cho mắt, bước sóng 1,54um, tần lặp 10 hz

yf • Hfli thto lCT.rda06 Proceedings of ICT.rda'06 Hanoi May 20-21.2006 DESIGNING EYESAFE LASER RANGEFINDER OPERATING AT 1.54 ^m AND 10 HZ-REPETITION Che tao may xa laser, an toan cho mat, bir6rc song l,54^m, tan lap 10 Hz Ho Quang Quy, Pham Vu Thinh, Nguyen Trong Tuan, Le Thanh Hai, Tran The Anh, Tran Thai Binh Abstract In this paper we present the designs and development of eyesafe laser rangefinder (ESLRF), operating at 1,54pm wavelength and withlOHz repetitive Base on modern technology and valuable and rare components, some important of ESLRF parts are studied and designed The operating principle and characteristical parameters of it are presented in detail Keywords: Laser range finder, Eye-safe wavelengh, optical parametric oscillator, high repetition INTRODUCTION A laser range-finder (LRF) is a device that calculates the distance to target by measuring the time it takes the laser light to travel a round-trip path from the laser transmitter to the target and back to the receiver [3.9.10] There are two typical classes of LRF: pulse RLF that use direct (incoherent) detection receivers and modulated continuous wave (CW) LRF that use heterodyne or coherent detection are classified as laser radar [9] The neodymiumdoped Yttrium Aluminum Garnet (Nd: YAG) laser has been the work-horse of armed forces world-wide for LRF applications since replacing the ruby laser in late 1960s [1,2,4,5] Raman-shifted Nd: YAG, OPO-Nd: YAG and erbium-doped glass (Er: Glass) lasers were developed in the late 1970s to mid1980s as eye-safe alternatives to the Nd: YAG laser [3,6-8,10,11] These lasers also provide improved performance in poor weather and smoke and are expected to supplant the Nd: YAG LRF for most single-function tactical range-finding applications As a result, the Nd: YAG laser remains the only laser in use today for designator applications and has also become the basis for range-finder-designatoi all dual-function applications, with Raman shifting and optica! parametric oseillator-OPO providing £ compatible eye-safe (>1.5p.m) mode foi range-finder and training One of important parts of LRF is the lasei receiver, which consists of sensitivit) photodiode and electric circuit To increasE the sensitivity and decrease the noise oi receiver, operating at convenience wavelength, a lot of missions have beer investigating Till now, a lot of classifiec photodiodes have been produced, bu' investigating in detail to use them for LRF remains a complicated question[15] Furthermore, many optical systems, as telescope, narrow band filter, going togethei the eye-safe-wavelength transmitter anc receiver must be provided In this report we present the principle o: eye-safe LRF, design of some important o; LRF parts by modem technology and valuabk rare components, characteristical parameters OPERATION PRINCIPLES 2.1 Operation principle The operating principle of ESLRF is described in Fig Ky yeu HQi thto ICT.rda'06 Proceedings of ICT.rda'06 Hanoi May ^^^^^^^^^P^^^^^ QP^.^.>^}^^^^^i^;^^^;%^^g^ Fig.2 Sketch of OPO Fig.l Operating principle The principle parts of ESLRF are: 1) the laser head YAG:Nd'* to generate a laser beam at 1.06pm wavelength; 2) the optical transmitter to reshape the divergence beam to parallel one and to point it at target; 3) the detector to record the start moment; 4) the power supply for laser with sofware to control the generating repetition; S) the OPO to converse the wavelength of laser beam from 1.06|Jm into l.S4pm; 6) the optical receiver to collect the scattered laser beam back from target and to focus it on the face of detecter; 7) the detector to record the stop moment; 8) the counter with comparator to count the distance; 9) the indicator LCD to display the date, the time and measured distances The odier is 85% reflectivity for laser light and 0% for 1.06pm or mirrors are leaned against ruber wasl the washer and the cover, the co-a> tuning of optical elements (crystal a mirrors) is done Fig.3 Completed OPO 3.2 Optical transmitter and receiver The optical transmitter is designed described in Fig.4 and Fig,5 DESIGN 3.1.1,064 Mni-54pm OPO The OPO is designed and described in Fig.2 (structure) and Fig.3 (panorama) The LiNbOs with diamension of x x [cm' ], is cut at phase-matching angle 43° Two side faces are polished and coated by antireflective layer for 1.54 pm laser light This crystal placed between two mirrors, one of them with 90% reflectivity for 1.54pm laser light and 0% for 1.06pm one Fig.4 Sketch ofTransmiter The transmitter consists of ei components prepared for 1.54 pm laser lie 1) the first splitter drives a little of laser be to detector; 2) infront of photodiode there i positive lens to focus laser beam photodiode; 3) the negative lens I Hfli thto ICT.rda'06 Proceedings of ICT.rda'06 Hanoi May 20-21, 2006 3.3 Detector with preamplifler photodiode InGaAs Fig Optical Transmitter extends laser beam; 4) the positive lens with negative lens reshapes laser beam to be parallel; 5) two mirrors drive the image light from target to eye of observer; 6) two positive lenses focus image light on eye There are two important problems: the first, all optical are AR coated and high transmissive for 1.54/ym laser light; the second, axises of transmitter and observation occular must be parallel with high accuracy The optical receiver is designed and described in Fig.6 and Fig.7 As so as transmitter, all optical parts of it are made, using materials non-absorable and high transmissive for 1.54/;m laser light The Detector for ESLRF is designed basing on 8C443 PIN/Preamp InGaAi photodiode It is designed for FDDT, ATM and SDH/Sonet up to 155Mbps The AGC (Automatic Gain Control) ensures a wide dynamic range Its double-lens optical systen: is designed with diameter 62.5 pm The Optical and Electrical Characteristics of it are: responsivity of 200 kVAV at 1550nm lasei light, output voltage of 1.2 V, bandwith oi 140 MHz, noise-equivalent power of 15 nW dynamic range of 36-^40 dB, output resistance of 50Q, power supply current of 32-r40 mA, Its absolute maximum ratings are: supply voltage VDO-VSS from of to max of 6.C V, operating temperature from of -40 tc max of 85 °C, storage temperature form of -55 to max of 125 °C The principle diagram of preamp-lnGaAs phododidoe is described in Fig.8 and designed detector is described in Fig.9 -w- VDD DATA, w DA TAc Vss Fig Principle diagram of preain detector 8C443 Fig Sketch of Receiver But two spherical mirrors must be high reflective for X.SApm laser light ••.- ' -',•1 ^ , - M H 'M'V' ?> ^^ Fig 10 Designed detector 3.4 Power supply Fig Optical Receiver The power supply plays three roles: 1} supplies pump lamp with energy, 2) trigei pulse and 3) control repetition regime foi Ky yeu HQi thto ICT.rda'06 generation of laser and of counter and indicator Proceedings of lCT.rda'06 Hanoi May 20-2 One can see that in the range from V 1700 nm wavelength of laser ligh responsivity is high Since, it is da specially for 1300nm and 1500 nm, usefull for ESLRF Fig 11 Designed power supply gn The most important components are TL494 with controler sofware and triger oscillator This power supply can operate up to OOHz The voltage can change from V to 1500V in pulse for pump lamp (Fig.l 1) 1100 1300 1500 1700 1900 Wavtltngti (nm] Fig 13 Responsivity spectra of 8C443 preamp InGaAS photodiode 3.5 Counter and distance indicator The counter is designed for ESLRF oprerating with lOHz repetition and distance error ± \m The most important components are the crystal I55-a clock 155MHz and the IC EMP706AE They are two components is valuable and rare The indicator is a LCD with sofware to indicate measured results in screen as: date, time, matrix of distance values with six rows and eight columns Thee results can be saved in memory The designed indicator is in Fig 12 Fig 12 Designed indicator 4.2 The laser pulse duration The YAG:Nd laser, oprerating with 11 repetition is modulated by crystal YAG:' The duration of its gigant pulse about i energy of 50, 40 and 20 mJ, meanwhile compareting single-pulse laser LRF genei pulse of 7ns (Fig 14) Fig 14 Pulses of single (left-up) and lOHz lasers (50, 40 20 mJ) CHARACTERISTICS OF ESLRF 4.1 Responsivity spectra The responsivity spectra of preampInGa.As photodiode is described in Fig 13 4.3 Laser energy- supplied voltage By regulating function of power supp the energy supplied the lamp can be chang so the energy of the laser beam is chang* j ^ j ^ J ^ i thto ICT.rda'06 Proceedings of ICT.rda'06 Hanoi May 20-21.2006 The lasc energy-voltage characteristic is described in Fig 15 From Fig 17 can see that, the laser energy reaehs the saturable value, although the supply voltage increases up to high value as possible T.B.Chu, P.V.Thinh, H.Q.Quy, Commu Phys 5,2,12-16 0995) in 10 Clifton S Fox, Ed Active Electro-Optical System, V.6 (1996) 11 H.Q.Quy, The operation principle oj 'Intelligent weapons" Special issue for MST&T,2I,6(I997) 12 Guang S He, Song H Liu, Physics oj nonlinear optics World Scientific, (1999) E 120 •100 p ao 13 W Koechner," Solid-state laser Engineering", Springer- Verlag Berlin Heidelberg, p.747 (1999) 60 _« 20 0 200 400 600 800 Supply Voltage [V] Fig 15 Laser Energy- Supply voltage characteristic 14 Tr.B.Chu, H.Q.Quy L.Th.Q.Anh, Some methods for wavelength tuning of solid-state lasers, using for military, T Technics & Equipments, No 7+8 (2000) 15 H.Q.Quy, The operating principle of the laser5 CONCLUSION Most of ESLRF's important parts are designed and its parameters are measured All of them are in good agreement with requests for ESLRF operating at 1.54fa.m wavelength of with OHz repetition Tai li^u tham khao S.K.Kurtz, "Materials for nonlinear optics' Laser Handbook, North-Holland Ed F.T.Arechi and E.O Shulz, Dubai, 1970 R J Pressley, Handbook of laser with selected data on optical technology, Cleveland (1971) J W Strobeln Laser Beam Propagation in The Atmosphere: Topics in Applied Physics, V.25 -Berlin; N.Y.: Springer (1978) Cnpaeo^HUK no nasepaM, MocKsa CoBercKoe paflno (1978) M.Demtroder, Laser Spectroscopy, Kaiserlautem(I98I) B.r flMMtpneB, TapacoB Jl B npuKnadnaft HefiUHeOnap onmuKa.- Ma PaAM0MCBn3b(l982) H.Q.Quy, T.B Chu, J Tech Phys 32,4,347.153(1991) H.Q.Quy T.B.Chu, J Technical Physics, V.38, No.4 (1994) guided weapons and laser equipments for militaiy actions Special issue for Applied Physics 12 (2003) 16 P Elmer Optoelectronics: " High Peifomance Flash and Arc Lamps", p.40 (2004) 17 A/em6f;j.mijry.com/don/donflash.html Proceedings of lCT.rda'06 Hanoi May Ky y6u Hpi thto ICT.rda'06 Authors ki^:^ ProfDr Ho Quang Quy received the Mater degree of Theoretical Physics from the Nicolai Copemic University in 1978 and Mathematic-Physic Ph.D degree from Military Institute for Technics in 1992 He joined the Laser Technology Laboratory in 1978 where he has been working in the area of Laser Theory, the Nonlinear Optics and Laser Applications Email: hoquyl253@yahoo.com Mr Master Tran received the Degree in 19! Technical I Ilmenau and Mast in 2000 from Le University He jc Infrared- Optic L in 1985, where he working in the designing and repa infrared equipments Dr Pham Vu received the Maste of Physics in 19 Physic Ph.D degree from Minsk Univer: joined the Laser Tec^ Laboratory in 1977 he has been working area of laser Teel and Applications B.Sc Nguyen Trong Tuan received the Bachelor's degree of Laser Physics from the Sofia University Bulgaria in 1976 He joined the Laser Technology Laboratory in 1977, where he has been working in the area of Laser Theory, the Nonlinear Optics and Laser Applications Rd ... Optical transmitter and receiver The optical transmitter is designed described in Fig.4 and Fig,5 DESIGN 3.1.1,064 Mni-54pm OPO The OPO is designed and described in Fig.2 (structure) and Fig.3 (panorama)... oprerating with lOHz repetition and distance error ± \m The most important components are the crystal I55-a clock 155MHz and the IC EMP706AE They are two components is valuable and rare The indicator... The optical receiver is designed and described in Fig.6 and Fig.7 As so as transmitter, all optical parts of it are made, using materials non-absorable and high transmissive for 1.54/;m laser light