Pure Photonics is a value-add distributor of NeoPhotonics Tunable External Cavity Laser (ECL) technology. Pure Photonics is modifying this superior and field-proven tunable laser for the Telecom industry to meet the stringent requirements of high Signal-to-Noise-Ratio applications. The product comes in an ITLA formfactor, ensuring easy digital communication and controls, and has an optimized firmware and electronics configuration to bring out superior performance.

Tunable Laser Technology Benefits

The Pure Photonics tunable laser solution makes a field proven, high-volume telecommunications laser suitable for the high-demanding applications that are typically addressed by hand-crafted custom solutions. Not only does the technology provide optical performance at-par with the existing solutions, it does so in an extremely small form-factor and a tuning range in excess of 35nm. Tunability allows our users to provide products that have an enhanced functionality (e.g. environmental sensing for multiple elements) and to significantly reduce leadtime and inventory cost.

Thanks to the ECL design, the intrinsic linewidth of the product is extremely narrow. No other volume manufactured tunable laser product can approach the 10kHz intrinsic linewidth that this product offers. In addition, thanks to a very stable design, without moving parts or current-injected tuning sections, the noise at lower frequencies is also impressive.

With the low loss external cavity, the output power from the laser can be as high as 18dBm. And the unique tuning control technology enables the laser to switch to any-frequency within its tuning range. 

Operating Principle

The optical cavity is formed by a gain chip and an external cavity with a high-reflection end-mirror. Within the cavity two Silicon etalon filters are positioned with a slightly different Free-Spectral-Range. The combined transmission curve, through the Vernier effect, selects the dominant laser peak. The frequency, in this way, can be independently tuned by changing the temperature of the filters, and the power can be independently tuned by changing the injection current in the gain chip.

The product is provided with a full electronic circuitry that controls all the major functions of the product: the power is controlled through an integrated photo-diode, the temperature of the filters is controlled through temperature sensors and the frequency lock is controlled through an imposed 888Hz dither signal. Thanks to the on-board micro-processor, the user only needs to provide digital commands (e.g. 'set channel x', 'turn laser on', etc) and does not need to control the underlying technology. 

The described product has been deployed in high volume by NeoPhotonics over the last 10 years and it has proven to be a very stable and high performance platform. Pure Photonics is now enhancing this product by providing significant reductions in laser FM and AM noise, as well as by enabling new operation modes, such as fast frequency sweeps, fast switching and full-band sweeping. This is done through optimization of control algorithms and an experience and experiment driven improvement of electronics.