Electronic wavelength tuning using acoustooptic tunable filter with broad continuous tuning range and narrow channel spacing

The use of acoustooptic tunable filters as tunable-wavelength filters in a multiwavelength network is reported. Fast ( approximately=3 mu s access time), broad, continuous tuning (1.3-1.56 mu m) and narrow channel spacing (4.5 nm) in a nine-channel distribution system were demonstrated. The combination of broad tuning range and narrow channel spacing allows channel selection in a distribution system with hundreds of wide-band wavelength-division-multiplexed channels. The wavelength switching time, measured as approximately=3 mu s, is important in many high-speed switching applications.<>     

一种面向多标准无线收发器的低功耗宽调谐范围基带滤波器设计

本论文提出了一种面向多标准收发器的具有精确片上调谐电路的低功耗宽调谐范围基带滤波器。设计的滤波器是由三级Active-Gm-RC类型的双二次单元级联组成的六阶巴特沃斯低通滤波器。采用改进的线性化技术来提高低通滤波器的线性度。论文提出了一种新的匹配性能与工艺无关的跨导匹配电路和具有频率补偿的频率调谐电路来增加滤波器的频率响应精度。为了验证设计方法的有效性,采用标准的130nm CMOS工艺对滤波器电路进行流片。测试结果表明设计的低通滤波器带宽调谐范围为0.1MHz-25MHz,频率调谐误差小于2.68%。滤波器在1.2V的电源电压下,功耗为0.52mA到5.25mA,同时取得26.3dBm的带内输入三阶交调点。     

Wide and continuously tunable (30 nm) detector with uniformcharacteristics over tuning range

A wide and continuously tunable detector with a tuning range of 30 nm (Δλ/λ=3.7%) is demonstrated. Uniform responsivity of ~0.13 A/W and a linewidth of ~5 nm is achieved over the tuning range. This device is well suited for both single and multimode, dense and sparse channel separation WDM applications     

Wide range electronically tunable component multipliers

An operational transconduciance amplifier (OTA)-based good quality, wide-range electronically tunable module for resistance and capacitance multipliers has been realized. Its multiplication factors are conveniently tunable with the bias-control current or voltage of the OTA over three decades. The module with slight modifications realizes temperature-insensitive multipliers. The circuit is very suitable for microminiaturization and is expected to find wide practical applications. Experimental results are also included.     

Wide wavelength tuning of sampled grating tunable twin-guide laser diodes

Tuning characteristics of widely tunable twin-guide (TTG) laser diodes with sampled gratings (SGs) are reported. Two SGs, providing slightly different reflection spectra, enable wide tunability by means of Vernier effect tuning. The device structure is vertically integrated and, hence, a DFB-like laser is obtained, which makes a phase tuning section unnecessary and facilitates easy and fast device characterisation. Although the tuning section can tune the SG reflection spectra by only /spl sim/2 nm, an overall tuning range of 28 nm has been achieved by employing Vernier effect tuning. Within the aforementioned tuning range, five supermodes are usable and can be tuned continuously without any mode-hops. The lasers operate at /spl sim/1.55 /spl mu/m wavelength and achieve a maximum output power of 12 mW.     

A low power Gm-C filter with on-chip automatic tuning for a WLAN transceiver

正A sixth-order Butterworth Gm-C low-pass filter(LPF) with a continuous tuning architecture has been implemented for a wireless LAN(WLAN) transceiver in 0.35μm CMOS technology.An interior node scaling technique has been applied directly to the LPF to improve the dynamic range and the structure of the LPF has been optimized to reduce both the die size and the current consumption.Measurement results show that the filter has 77.5 dB dynamic range,16.3 ns group delay variation,better than 3%cutoff frequency accuracy,and 0 dBm passband IIP3.The whole LPF with the tuning circuit dissipates only 1.42 mA(5 MHz cutoff frequency) or 2.81 mA(10 MHz cutoff frequency) from 2.85 V supply voltage,and only occupies 0.175 mm~2 die size.     

Broadly wavelength-tunable external cavity lasers with extremely low power variation over tuning range

Tunable external-cavity lasers with low power variation over a broad tuning range are demonstrated using asymmetric multiple quantum-wells with a wide and flat gain. For a 2.8-/spl mu/m-wide ridge waveguide laser of cavity length 380 /spl mu/m, when used in a grating external cavity and with an antireflection coating on one facet of laser diode chip, the power variation of less than -1 dB is obtained over a range of 80 nm. This extremely low power variation is a direct result of the spectrally flat gain.     

A low power Gm-C filter with on-chip automatic tuning for a WLAN transceiver

A sixth-order Butterworth Gm-C low-pass filter(LPF)with a continuous tuning architecture has been implemented for a wireless LAN(WLAN)transceiver in 0.35 μm CMOS technology.An interior node scaling technique has been applied directly to the LPF to improve the dynamic range and the structure of the LPF has been optimized to reduce both the die size and the current consumption.Measurement results show that the filter has 77.5 dB dynamic range,16.3 ns group delay variation,better than 3% cutoff frequency accuracy,and 0 dBm passband IIP3.The whole LPF with the tuning circuit dissipates only 1.42 mA(5 MHz cutoff frequency)or 2.81 mA(10 MHz cutoff frequency)from 2.85 V supply voltage,and only occupies 0.175 mm2 die size.     

A tunable waveguide CO2 laser with expanded tuning range

A method of expanding the tuning range of the CW CO₂ waveguide laser making use of a Fabry-Perot type light modulator is proposed. A preliminary experiment has been done to confirm the workability of the proposed scheme.     

Continuously tunable long-wavelength MEMS-VCSEL with over 40-nm tuning range

This letter presents for the first time an electrically pumped tunable vertical-cavity surface-emitting laser (VCSEL) with a record-breaking tuning range of 40 nm at long wavelengths. The VCSEL is based on a two-chip concept. The laser peak can be tuned continuously and without mode-hopping in a wavelength range above 1.55 /spl mu/m due to a microelectromechanical movable mirror membrane. The VCSEL is single mode all over the tuning range with a 32-dB sidemode suppression ratio. The laser emits a maximum output power of 100 /spl mu/W in continuous-wave operation at room temperature. Dynamic measurements of the tuning characteristics show that the 3-dB cutoff frequency for an electrothermal wavelength modulation is about 500 Hz and the 1/e-time constant of the step response is about 1 ms.     

Increasing input power dynamic range of SOA by shifting thetransparent wavelength of tunable optical filter

Gain-saturation-induced self-phase modulation (SPM) leading to pulse distortion in a semiconductor optical amplifier (SOA) is overcome by shifting a tunable optical filter (TOF). A recovered or broadened pulse can be obtained after filtering the amplified pulse in the SOA even if the short pulse is only 2-3 ps long. The input power dynamic range (IPDR) can be strongly increased by shifting the TOF and the direction of the shifted transparent wavelength is different for 10 Gb/s return-to-zero (RZ) or nonreturn-to-zero (NRZ) signals. The transparent wavelength of the TOF should be shifted to a longer wavelength for RZ signals and to a shorter for NRZ signals. 80-Gb/s optical time division multiplexing (OTDM) signal amplification in the SOA is demonstrated for the first time. We also demonstrate that a large IPDR for the 80-Gb/s OTDM signal can be obtained by shifting the TOF     

MEMS tunable SOI waveguide Bragg grating filter with 1.3 THz tuning range for C-band 100 GHz DWDM optical network

A MEMS tunable integrated waveguide Bragg grating-based filter for C-band optical dense wavelength-division multiplexing (DWDM) network is presented and analyzed in this work. Waveguide Bragg grating being a notch filter in the transmission spectrum is used to realize a tunable filter by varying the applied voltages to the fixed–fixed beam loaded with this grating. The strain across the grating is enhanced by choosing MEMS beam configuration such that the metal electrode is the bottom-most layer of the composite fixed–fixed beam. Device dimensions are chosen to achieve a narrow full width half maximum of 0.77 nm, allowing filtering of adjacent channels of 100 GHz DWDM network. A large Bragg wavelength shift of 10.4 nm (1552.52–1562.92 nm) was achieved at 45.8 V actuation providing tuning for 14 DWDM channels with inter-channel cross talk below ? 21 dB, with tuning range of 1.3 THz.

     

Record tuning range of InP-based multiple air-gap MOEMS filter

Continuously tunable Fabry-Perot filters based on multiple InP/air-gap MOEMS technology are presented. Record wavelength tuning >112 nm with an actuation voltage of only 5 V is demonstrated. The FWHM remains constant over the entire tuning range. The stopband covers both the second and third optical telecommunication window (1250-1800 nm).     

UHF double dielectric resonator filter with linearised tuning range

A UHF double dielectric resonator filter operating in the TE_01δ mode has been constructed with a high Q, wide (14%) and reasonably linear tuning range. This has been achieved by varying the gap between the resonators, and using the influence of the end wall on the movable resonator. The experimental device is readily scaleable to the cellular radio wave bands     

Ultra-compact MMIC active bandpass filter with wide tuning range

A very wide tuning range CMOS MMIC bandpass filter is implemented using active coupled resonators and experimentally demonstrated. It can realise a 0.51 GHz frequency tuning range around 1.8 GHz using a single control voltage, with an ultra-compact size of 0.28 mm and a very low DC power consumption of 41 mW.     

Performance analysis of a low power low noise tunable band pass filter for multiband RF front end

This paper presents a low power tunable active inductor and RF band pass filter suitable for multiband RF front end circuits. The active inductor circuit uses the PMOS cascode structure as the negative transconductor of a gyrator to reduce the noise voltage. Also, this structure provides possible negative resistance to reduce the inductor loss with wide inductive bandwidth and high resonance frequency. The RF band pass filter is realized using the proposed active inductor with suitable input and output buffer stages. The tuning of the center frequency for multiband operation is achieved through the controllable current source. The designed active inductor and RF band pass filter are simulated in 180 nm and 45 nm CMOS process using the Synopsys HSPICE simulation tool and their performances are compared. The parameters, such as resonance frequency, tuning capability, noise and power dissipation, are analyzed for these CMOS technologies and discussed. The design of a third order band pass filter using an active inductor is also presented.     

宽调谐范围三频共线输出染料激光器

一种宽范围连续调谐的三波长共线、时间同步输出的染料激光器。使用R560/DCM乙醇混合溶液,激光调谐范围为554～667nm。采用相关补偿调谐原理,容易在560～640nm范围实现三波长激光的强度比均1:1:1的控制,并获得了高功率放大运转。     

Electro-optically tunable wavelength demultiplexer using depressed index waveguides

A novel configuration of an integrated optical tunable wavelength demultiplexer with a stable channel spacing is proposed. The structure consists of a three-mode depressed index diffused waveguide with single-mode input and output waveguides. The refractive index depression has been designed using experimental data of double diffusion of MgO on Ti:LiNbO/sub 3/ waveguides. The BPM simulation of the structure supports the feasibility of the device and shows a good wavelength tunability.<>     

A tunable filter using amplifier pole

A circuit consisting of two periodically operated switches, potentiometers, resistors, and compensated operational amplifiers, but not containing external capacitors, is proposed for the realization of a second-order bandpass and low-pass filter. The filter is electronically tunable and the natural frequency of the filter varies linearly with the width of the pulses controlling the FET switches.