Dynamic gain equalizer using proposed adjustment procedure for thermooptic phase shifters under the influence of thermal crosstalk

A dynamic gain equalizer (DGE) is required to automatically compensate for gain variations related to fiber amplifiers. This paper proposes a DGE with thermooptic (TO) phase shifters based on a single-filtered-arm interferometer. A design procedure was newly developed for the control of the TO phase shifters, which could be used to accurately control the intended attenuation profile in one adjustment. In this procedure, the Taylor series method was used as an optimization algorithm, and thermal crosstalk was taken into account. From the point of view of thermal crosstalk, the behavior of phase shifters in an array and the effect of three-dimensional (3-D) trenches formed around the phase shifters were precisely investigated. A DGE module based on 1.5%-/spl Delta/ planar lightwave circuits and the 3-D trench structure are demonstrated. The measured spectra were found to be in good agreement with arbitrarily designed profiles under open-loop control, even when there was some thermal crosstalk between phase shifters. The results indicate that the design procedure and the estimation of the thermal crosstalk are effective for accurate control of the DGE.

[1]  Hartmut Hillmer,et al.  Investigations of thermal crosstalk in laser arrays for WDM applications , 1998 .

[2]  Takafumi Tanaka,et al.  Beam-adjustment-free crosstalk reduction in 10 GHz-spaced arrayed-waveguide grating via photosensitivity under UV laser irradiation through metal mask , 2000 .

[3]  K. Jinguji,et al.  Synthesis of coherent two-port lattice-form optical delay-line circuit , 1995 .

[4]  J. A. Walker,et al.  Dynamic spectral power equalization using micro-opto-mechanics , 1998, IEEE Photonics Technology Letters.

[5]  Namkyoo Park,et al.  Actively gain-flattened erbium-doped fiber amplifier over 35 nm by using all-fiber acoustooptic tunable filters , 1998 .

[6]  C.H. Joyner,et al.  Integrated WDM dynamic power equalizer with potentially low insertion loss , 1998, IEEE Photonics Technology Letters.

[7]  H. Okano,et al.  Thermo-optically switchable drop filter with photoinduced Bragg grating on silica-based waveguide , 1998 .

[8]  Arrayed waveguide dynamic gain equalization filter with reduced insertion loss and increased dynamic range , 2001, IEEE Photonics Technology Letters.

[9]  C. Doerr,et al.  Dynamic wavelength equalizer in silica using the single-filtered-arm interferometer , 1999, IEEE Photonics Technology Letters.

[10]  M. Aaron,et al.  The Use of Least Squares in System Design , 1956 .

[11]  K. Sato,et al.  Experimental investigation of thermal crosstalk in a distributed feedback laser array , 1991, IEEE Photonics Technology Letters.

[12]  C.R. Doerr,et al.  16-band integrated dynamic gain equalization filter with less than 2.8-dB insertion loss , 2002, IEEE Photonics Technology Letters.

[13]  High resolution dynamic gain equalizer using super-high /spl Delta/ planar lightwave circuit technology , 2003, OFC 2003 Optical Fiber Communications Conference, 2003..

[14]  S. Chandrasekhar,et al.  An automatic 40-wavelength channelized equalizer , 2000, IEEE Photonics Technology Letters.

[15]  Smart dynamic wavelength equalizer based on an integrated planar optical circuit for use in the 1550-nm region , 1999, IEEE Photonics Technology Letters.

[16]  T. Saida,et al.  Dynamic gain equalisation filter based on integrated optical transversal filter with asymmetric combiner , 2002 .

[17]  Akira Himeno,et al.  New structure of silica-based planar lightwave circuits for low-power thermooptic switch and its application to 8 /spl times/ 8 optical matrix switch , 2002 .

[18]  H Melchior,et al.  Overlapping-image multimode interference couplers with a reduced number of self-images for uniform and nonuniform power splitting. , 1995, Applied optics.

[19]  Masao Kawachi,et al.  Bridge-Suspended Silica-Waveguide Thermo-Optic Phase Shifter and Its Application to Mach-Zehnder Type Optical Switch , 1990 .

[20]  Smart dynamic wavelength equalizer with on-chip spectrum analyzer , 2000, IEEE Photonics Technology Letters.

[21]  Jung-Chih Chiao.  Liquid-crystal optical harmonic equalizers , 2001, 2001 Digest of LEOS Summer Topical Meetings: Advanced Semiconductor Lasers and Applications/Ultraviolet and Blue Lasers and Their Applications/Ultralong Haul DWDM Transmission and Networking/WDM Compo.

[22]  T. Goh,et al.  Low-power consumption silica-based 2 x 2 thermooptic switch using trenched silicon substrate , 1999, IEEE Photonics Technology Letters.

[23]  M. Parker,et al.  Dynamic holographic spectral equalization for WDM , 1997, IEEE Photonics Technology Letters.

[24]  F. Horst,et al.  Adaptive gain equalizer in high-index-contrast SiON technology , 2000, IEEE Photonics Technology Letters.