Optoelectronics and MOEMs
980 nm Pump Laser Diode
CSIR-CEERI has developed 980 nm pump laser diode for erbium-doped fibre amplifier (EDFA). The laser diode has ridge waveguide structure with two InGaAs strained quantum wells as active layers with graded index AlGaAs for waveguide and cladding layers. Front and rear facets of laser diode have been coated with λ/4n thick Al2O3 anti-reflection (AR) and two pairs of Al2O3/Si high reflecting (HR) layers using RF magnetron sputtering. Finally, laser chips are mounted in industry compatible 14-pin butterfly package. The device can be used for EDFA-based in Optical Fiber Communications applications. The activities were sponsored by DIT and CSIR.
Chip Level Specifications:
- Cavity length: 1.5 mm
- Ridge/Chip width: 3 mm/ 400 mm
- Wavelength: 980 nm ± 10 nm
- Threshold Current, Ith: 35 mA
- Output Power: 160 mW
- Temperature: 25 deg C
Package Level Specifications:
- Package: 14 PIN Butterfly
- Drive Current: 350 mA
- Output Power: 95 mW
- Gain @ 1550 nm in EDFA block: 14 dBm
- Temperature: 25 deg C
1 x 8 Optical Power Splitter
This device is used for splitting/ branching the power of a light transmitter into eight number of subscriber equally. The device is made of silica-on-silicon material and designed for single-mode operation at wavelength of 1550 nm. Input and outputs of the device are pigtailed with 1-channel and 8-channel v-grooved fiber-array ribbon respectively and packaged thereafter. It is used for splitting of power in optical communication, particularly, in fiber-to-the-home (FTTH) and CA-TV applications. The activity was sponsored by CSIR.
Package level specifications:
- Operating wavelength : 1550 nm
- Underclad (SiO2): no=1.445, Thickness =15 mm
- Core (Ge-SiO2): nc =1.449, Thickness = 8 mm
- Upperclad (BPSG): no =1.445, Thickness =12 mm
- Dn, Index Difference: 0.30 %
- Port to Port Spacing: 250 mm
- Avg. Insertion loss: 15.0 dB
- Uniformity: 2.5 dB
Long-period waveguide gratings (LPWGs)
Corrugated Long-Period Waveguide Gratings (LPWGs) in silica-on-silicon material has been realized for the first time at CSIR-CEERI for integrated-optic communication and sensing applications. The device is realized by making periodic corrugation on top of a relatively high-indexed (refractive index contrast of 8%) Ge-doped silica waveguide, which is sandwiched between un-doped silica under-cladding and boro-phospho-silicate-glass over-cladding layers. Resonance wavelength of the 15-mm-long waveguide grating is found at ~1581 nm. The device can be used as band-reject and band-pass filter in communication and electrically passive temperature sensing applications. The activity was sponsored by DIT.
|LPWG parameters||Material Parameter||Specification achieved|
|Waveguide width = 6 micron, Waveguide height = 6 micron, Waveguide length = 30 mm, Grating length = 15 mm, Grating period = 228 micron, Tooth-height = 85 (+/- 5) nm.||Substrate: Silicon Under-cladding: Un-doped SiO2 (thermally deposited): RI (1.445), Thickness (15 micron), Core: Ge-SiO2 (PECVD): RI (1.457), Thickness (6 micron), Over-cladding: BPSG SiO2 (PECVD): RI (1.445), Thickness (6 micron).||
Grating resonance wavelength: Tunable across L-band. 1577 – 1584 nm for Temp.: –30 to +70°C.
Grating strength: 9-11 dB (quasi-TE), 7-9 dB (quasi-TM).
Bandwidth (FWHM): ~ 7 nm.
Operating temperature: -10°C to +70°C.
Loss: Low-loss design; total loss: ~ 4.4 dB for device length of 30 mm (including input and output coupling losses).
Polarization: Polarization-independent (at room temp.)
GaAs based Hall Sensor
Hall sensor is the world’s third largest sensor mainly used in automotive industry. CSIR-CEERI has developed fabrication technology for GaAs based Hall element. For device fabrication, n-type GaAs material has been used. The device can widely be used in automotive application in addition to temper-proof energy metering application. The activity was sponsored by Aeronautical Development Agency (ADA) under NPMASS programme.
- Device dimension: 400 µm × 800 µm
- Output Hall Voltage, VH : 48 – 66 mV (for B = 200 mT, I = 15 mA)
- Input Resistance, Rin : 297 – 326 W (for B = 0 mT, I = 1 mA)
- Output Resistance, Rout : 299 – 331 W (for B = 0 mT, I = 1 mA)
- Offset voltage: 2.06 mV
- Sensitivity: 143 V/AT
GaN-InGaN LED devices and Solar-powered LED lamp
GaN-InGaN material based blue LED and phosphor-coated white LED devices have been designed and developed at CSIR-CEERI. Epitaxial layers structures required for the device have also been grown at CEERI by using MOCVD reactor. Following optimization of various unit processes, blue LED devices have been fabricated and tested. Ce-doped YAG yellow phosphor is used to achieve white light from blue. Devices are packaged with ceramic heat-sink and plastic lens. Solar-powered lamp has been designed and developed in association with CEERI-Chennai Centre using an array of these indigenous LEDs with a target to achieve multi-LED multi-purpose solar-powered LED lamp for cost-effective rural application. Further development is under progress. The activity has been supported by CSIR through TAPSUN programme.
- LED Device:
- Chip size: 1×1 mm2 (Finger-type) IF= 20 – 700 mA at VF = 3 – 4 V
- Blue emission wavelength: 450 – 460 nm
- Efficiency (white): 33 lm/W at I= 20 mA, 30 lm/W at I= 50 mA, 25 lm/W at I= 100 mA
|Multi-LED solar-powered lamp||3-W|
|LED||12 no. (indigenous, 3.2V, 0.5 A)|
|Solar Panels||0.975 W panels (2.5 V, 130 mA, each panel 0.32 W)|
|Total optical power (lumen)||90 lumen|
|Battery capacity||2200 mAh|
|FM Radio Receiver||✔|
|USB Flash Memory Reader||✔|
|Battery Protection Circuit||✔|
|Full charging time||8 hrs|
|Usage time||~ 6 hrs|
C-Band GaAs High Power MESFET Devices
C-Band GaAs material based power MESFET devices and modules have been designed, fabricated and tested at CSIR-CEERI through sponsored projects, entitled, Design and Development of C-Band High Power GaAs MESFETs (Phase I) and Design and Development of C-Band High Power GaAs MESFET Modules (Phase II). (Sponsored by SAC / ISRO)
Applications: Solid State Power Amplifiers for Satellite Communications
- Output Power : 2 – 2.5 W (Tested at SAC, Ahmedabad)
- Gain : 6 dB
- Frequency : 4 GHz
- Total Gate Width : 5.04 mm
Two-chip Module specifications:
- Output Power : 4.6 W (Tested at SAC, Ahmedabad)
- Gain : 9.2 dB
- Operating Frequency : 3.75GHz
- Technology Status: Technology transferred to GAETEC, Hyderabad through SSPL, New Delhi as per ISRO’s programme
Large Area InGaAs/InP Photodetectors
Large area photodetectors based on InGaAs/InP materials have been designed, fabricated and tested through In-house Development.
Application: Optical Power Meters
Chip level specifications:
- Chip size : 1.3 mm x 1.3 mm
- Active area : 1 mm diameter
- Breakdown voltage : > 20 V
- Responsivity : 0.83 A/W at 1310 nm; 0.99 A/W at 1550 nm
- Dark Current : < 50 nA at – 5 V
- Noise Equivalent Power : 70 nW (Measured at Optiwave Photonics, Hyderabad)
Technology status: Indigenously developed and demonstrated.